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GIFT OF
American Wire Rope
.
American Steel & Wire Company
Sales Offices
CHICAGO 72 West Adams Street
NEW YORK 30 Church Street
WORCESTER 94 Grove Street
BOSTON 120 Franklin Street
CLEVELAND Western Reserve Building
PITTSBURGH Frick Building
BUFFALO . ' 337 Washington Street
DETROIT Foot of First Street
CINCINNATI Union Trust Building
OKLAHOMA CITY State National Bank Building
ST. LOUIS Third National Bank Building
ST. PAUL-MINNEAPOLIS .... Pioneer Building, St. Paul
DENVER First National Bank Building
SALT LAKE CITY . . . Walker Bank Building
United States Steel Products Company
EXPORT DEPARTMENT: NEW YORK . . . 30 Church Street
PACIFIC COAST DEPART.: SAN FRANCISCO . . Rialto Building
PORTLAND, Sixth and Alder Streets SEATTLE, 4th Ave. So. & Conn. St. Los ANGELES, Jackson & Cent. Aves.
Warehouses
For the convenience of our customers, we have established ware- houses at different points throughout the country from which quick shipment may be made, as follows:
BALTIMORE KANSAS CITY, Mo. RICHMOND, IND.
BUFFALO Los ANGELES SALT LAKE CITY
CEDAR RAPIDS LOUISVILLE SAN FRANCISCO
CHICAGO MEMPHIS SAVANNAH
CLEVELAND NEW HAVEN, CONN. SEATTLE
COUNCIL BLUFFS NEW ORLEANS ST. Louis
DENVER NEW YORK ST. PAUL
DES MOINES PHILADELPHIA TRENTON, N. J.
DETROIT PITTSBURGH WICHITA
FARGO PORTLAND, ORE. WORCESTER, MASS
American Wire Rope
Catalogue and Hand Book
American Steel & Wire Company
Copyright 1913 by American Steel & Wire Company
,*•"• \
Issued January 1, 1933
5
Contents
Hand Book Section
Page Chapter I. Standard Methods and Facilities for Testing Wire
Rope. 10
Chapter II. Materials Composing Wire Rope and their Physical
Characteristics. 11-13
Chapter III. Standard Types of Wire Rope Construction — The
Strand and Various Combinations of Wires — "One-Size Wire"; " Warrington" and "Scale Type" Construction. Composition of the Various Classes of Rope— " Haulage," "Hoisting," "Extra Flexible," "Special Flexible," " Running Rope," etc. Abbreviated notation for describing Rope. The Structural advantages of different kinds of Rope, their susceptibility to abrasion, flexibility, strength, etc. Smooth and Flat Ropes, Regular and Lang's Lay. 14-26
Chapter IV. Variety of Uses for Wire Rope of the various types.
Examples showing the scope of Wire Rope adaptability. 27-28
Chapter V. Mechanical Theory of Wire Rope. Stresses in Rope from: — (1) Dead and Live Loads, (2) Bending, (3) Impact, on starting and stopping, (4) Slopes, (5) Spans. The maximum stress for Machinery in relation to the strength of the rope. The power derivable from multiple sheave blocks. Mathematical formulae and stress tables and graphical diagrams. Stresses in guys, and tables and diagrams for guy factors. Factors of safety advisable for various conditions of service. Sizes and kinds of rope for various stresses. 29-66
Chapter VI. Practical Hints and Suggestions. Gauging the diameter. Sheaves and Drums, Grooves, Overwinding, Alignment; "Lead" from Sheave to Drum; Wear of Sheaves and Drums. Disadvantages of High Speed, Reverse Bending and Sudden Stresses. Proper Handling of Wire Rope. Strength of Galvanized Ropes. Lubrication, Power Transmission and effect of Heat on Wire Rope. 67-70
Chapter VII. Instructions for Ordering Wire Rope. List of Items
of Information that should accompany orders. Illustrative Sketches. 71
Chapter VIII. Typical Applications of Wire Rope in Practice!
Aeroplanes, Cableways, Tramways, Cable Roads, Clam Shell and Orange Peel Buckets, Cranes, Derricks, Elevators of various kinds, Excavating Machinery, Dredges, Ferries, Guying, Loading and Unloading Machinery, Lumbering, Mining Machinery, Suspension Bridges, Stump Pulling, Towing and Oil Well Drilling. 72-118
Catalogue Section
Page
Chapter IX. Lists of Prices, Sizes, Strengths and Proper Diameters of Drums or Sheaves for Round and Flattened Strand Ropes, arranged in the order of their flexibility, commencing with the Least Flexible and running to the Most Flexible; in the following grades, viz.: (1) Iron, (2) Crucible Cast Steel, (3) Extra Strong Crucible Cast Steel, (4) Plow Steel and (5) Monitor or Improved Plow Steel ; and for the following purposes, viz.: Transmission, Haulage or Standing Rope, Hoisting, Tiller or Hand Rope, Galvanized Rigging or Guy Rope, Running Rope, Hawsers and Mooring Lines, Deep Sea Towing Hawsers, Bridge Cables, Sash Cord, Aeroplane Strands, Galvanized or Tinned Flexible Aeroplane or Motor Boat Cord, Mast Arm or Arc Light Rope, Sawing Strand for Sawing Sandstone, Clothes Lines, Special Strands for " Messenger " work, Catenary Con- struction and Lightning Arresters, etc. Round and Interlocked Tramway Strands and Flat Rope. Table of estimated average number of coils of hollow cable clothes line per barrel, packed. Description of Flat Rope, of method of repairing it. Description and prices of American Steel and Wire Shield Filler for lubricating purposes. 119-199
Chapter X. Lists of Prices and Descriptions of Special Equipment and Accessories — Fittings and Methods of Attachment. Methods of joining two Ropes, Thimbles, Clips, Clamps, open and closed Sockets, Regular and Bridge Type, Single and Sister Hooks, Swivels applied to Sockets, Thimbles and Hooks. 200-215
Locomotive Switching, Wrecking and Ballast Unloader Rope with Single and
Double Fittings. 216-219
Turnbuckles, Iron Guy Shackles, Heavy WTire Rope Blocks, Sheaves, Accessories,
Endless and Special Slings and Pulling in Cables. 220—229
Directions for Splicing, with Illustrations. 230-233
Tables of Power Transmitted, Weights of Materials Handled, Comparison of Strength of Wire Rope versus Manila Rope, Numbers, Dimensions and Capacities of Reels, etc. 234-238
Glossary of Terms used in the Wire Rope Industry. 239-243
Index. 243-247
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The Properties
THE trend of all Evolution is in the direction of greater adaptability of means to ends, and before entering upon the detailed discussions of the modern wire rope in all its variety of appli- cations it is eminently proper to investigate somewhat briefly its true inwardness as a mechanical device. By wire rope is here meant the rope of twisted wire, the successor of the twisted hemp rope, as distinct from the wrapped cable of straight parallel wires often used in suspension bridges. It is by no means as simple a contriv- ance as it appears, and a brief study of its construction and functions will throw a penetrating light upon how and why it has been respon- sible for the growth of several enormous industries.
Adaptability in an engineering sense means economy and safety. The wire rope excels in economy for many purposes because of its long life under heavy duty, and be- cause of its superiority in strength per unit of size and weight it is for many uses the only available appliance that has yet been de- veloped. Compared with its hemp- en predecessor it has the following peculiarities :
(1) Enormously greater strength for the same diameter.
(2) Much greater strength for the same weight.
(3) Equal strength whether wet or dry, which is decidedly not the case with a hemp rope.
of Wire Rope
(4) Constancy of length under all weather conditions.
(5) Uniformity of strength throughout its length and through- out its life when properly used and cared for.
(6) Greater certainty with which its strength can be computed.
(7) Greater indestructibility.
(8) Far greater variety in types of construction for different uses.
(9) Approximately the same flex- ibility for the same strength.
(10) Less softness for hand work.
(11) Greater rigidity under stress, and smaller range of elasticity.
(12) Lower cost per unit of strength.
The above list is not supposed to be complete, but it is believed to be fairly representative of all actual working facts. It is appar- ent that except under certain con- ditions governing (9), (10) and (11), the wire is a better material for the purpose than hemp.
A hemp rope is composed of three, or sometimes four, strands, each of which is formed by twist- ing together a comparatively large number of filaments or fibres. These filaments may be single threads of hemp or of yarn spun from a number of these threads or fibres. Since the original threads will seldom average more than three feet long, and often a good deal less than this, it is evident that the strand depends for its continuity of strength upon the binding action of the several helical
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fibres under tension in the manner illustrated below. The action of fibres in a strand is identical with that of strands in a rope.
Consider (Fig. 1) in section three circular strands, of equal length, whose centers are A, B and C, and which are laid parallel with each other untwisted and under no tension. Let their common length be denoted by L. Assume now that one end of the rope is fixed, and that the other end is rotated one complete revolution, still with- out tension. Then the axis of each strand will take the shape of a helix of which the radius of rotation is R, and the pitch is P, somewhat less than L. The length of the axis of each strand is L = V47r2 R2 +
JH
to — which equals 2H. Therefore
F = 2^ H, and the radial force per unit length of a strand =
Now apply to the rope a vertical tensile force 3T acting parallel to its axis, and which must act through each strand; and prevent the rope from untwisting by the force H, acting horizontally in each strand. These horizontal forces at each end of the rope form horizontal couples acting against each other and resisted by radial stresses N in the strands. The stress H may be compared to the tension in a band around a water tank resisting the radial forces of the water.
Let F = 2N, represent the entire sum of the radial forces in one circumference. Then the radial force per unit of circumference will
F be , and the forces perpendic-
ular to any diameter will amount
+ H2 = S2. Note that V must always be less than S, which ac- counts for the fact that in any rope the strength of the whole is less than the sum of the strengths
of the strands. -5 = tan / = ?— ^
If the angle of friction of the material composing the strands be less than /^, then the strands will tend to slide upon each other.
We are now in position to under- stand many of the observed facts about twisted rope of all kinds. In the hemp rope, the strands are made from yarns that are them- selves composed of parallel fibres of short length. It is manifest that the fibres would immediately pull apart upon subjecting the rope to tension were they not crowded together by the forces H. If H is sufficient as compared with V to securely bind the fibres to- gether, their tensile strength will be fully developed. Otherwise when brought under strain they would slide upon each other, and cause the rope to "pull out" with- out the actual breaking of the fibres. Wetting the hemp fibres will decrease their angle of friction, from which it follows that a hemp rope which is properly designed when dry to develop the proper friction to keep it from pulling out may have as much as thirty per
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Company
cent, less strength when wet. The smaller the pitch of the rope the smaller the value of V in proportion to S, and consequently the weaker the hemp rope per unit of diameter. It is therefore evident that if the hemp rope be not twisted enough the elements of it will pull apart, while if twisted too much it will yield in tension under less than its normal load.
In the above discussion we as- sumed an external couple equal to 3 R H at each end of the rope to prevent untwisting, assuming absence of friction between the strands. As a matter of fact this couple 3 R H is just what is pro- vided by the friction in the rope itself. It is very much reduced in practice by laying up the alternate layers of yarn and strands in op- posite directions, the twist of one layer acting from left to right, while the adjacent ones act from right to left.
The radial components of H tend to draw each strand into the axis of the hemp rope. Therefore, there is a limit to the number of strands that can be arranged around each other in stable equi- librium without a core. Thus three strands, in hemp rope practice, as we all know, make a stable struc- ture, no one strand having a tend- ency to crowd between the other two, while four strands theo- retically would tend to work into three in stable position with the fourth on the outside. Successful four-strand hemp ropes are on the market, the above-mentioned diffi-
culty having been overcome of late years by making the strands of special shape and winding with great care. Thus a much smoother hemp rope is obtained, which, with a longer pitch, should be corre- spondingly stronger than a three- strand hemp rope.
When a well made hemp rope is stretched beyond its strength, the friction from the H forces is so great as sometimes to cause enough heat to make the rope smoke; the fibres and strands approach each other with a reduction in the value of R, and the generation of internal heat amounting to the applied en- ergy. If A represents the length of the rope before stretching, and B its length just before yielding, then the amount of heat energy de-
T veloped is (A — B) — . The action
of a hawser used in warping a large vessel into dock against or across a strong tide strikingly exemplifies these facts.
As a rope comes under stress, being more or less elastic it stretches and the pitch increases proportionately. The angle O therefore increases and the ratio of V to H increases, and it thus, up to its elastic limit, becomes more capable of resisting a given load the more it is stretched. Now the pitch of the fibres in the strands of hemp rope is greater than that of the strands in the rope in propor- tion to their respective diameters. Therefore when stretched the yarns would reach their ultimate stress sooner than the strands, were not
American Wire Rope
IV
these latter given an initial stress by supplementary twisting during the process of manufacture. There is always some danger — in the older hand made ropes there was great danger — that the inner strands may actually break while the outer ones remain intact, thus leading to the gradual destruction of the hidden part of the rope which is not subject to inspection, and therefore without giving warn- ing of the loss of strength.
The main characteristic of a hemp rope is its flexibility, which is incidental to its twisted structure. The fibres, yarns and strands not being parallel to the axis of the rope, when the latter is bent around a block or sheave the ele- ments composing it are partially free to roll upon each other, thus adjusting themselves more or less to changes in the direction of the axis, and being subject to far less tension and compression in bend- ing than would be the case were they laid up parallel to the axis. They are, however, subject to some direct tension because they are not entirely free to roll, and it is this tension coupled with torsion and rubbing together in the rolling process that destroys any rope — either hemp or wire — going over a small sheave faster than one going over a large one. By the nature of this problem it is evident at first sight that a mathematical investiga- tion covering all the factors, particu- larly those of rolling and torsion in the individual wires, would be very elaborate and complicated and
would cover ground upon which we have but little experimental data, so it has not yet been at- tempted, but it is equally clear that the flexibility is very de- pendent upon the arrangement of the elements in the rope. Flexi- bility in a wire rope is increased by the insertion of hemp centers, etc. When a wire rope is not under stress the individual wires are pressed together only by the initial stress caused by the twist, and adjacent wires touch each other only at the helical loci of their common tangent points. When a heavy load is applied the wires are crowded together, generating a considerable amount of pressure between adjacent wires, and con- sequently compressing each other and the hemp centers if there are any. Hence, besides an elongation due to longitudinal strain, there is a lengthening caused by the change of pitch due to the lessen- ing of the mean diameter of the rope through the H forces described above. The unit strain for the same unit stress is therefore a good deal greater than in the case of a steel bar or wire. If X be the strain in the length P, and T be the tension on a steel area a, neg- lecting the strength of the hemp centers, which cannot be considered on account of the vast difference between the Modulus of Elasticity of hemp and that of steel, then
X T
— - is the unit strain and — is P a
the unit stress. Therefore E, the
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Modulus of the rope, will be —
X PT a
divided by — = . The quan-
Jr a X.
tity X is the only one that will be materially affected by the twisting of the wires, since a is the cross sectional area of the metal. We see that X will be much larger for a rope than for a bar or chain, and therefore E will be correspondingly smaller. It is apparent from the above that no one value of E will do for all kinds of wire rope; the more the twist and the larger the proportion of hemp in the rope, the larger will be the value of X and the smaller that of E. For practical purposes of ordinary computation a compromise value for the different classes of wire rope has been de- termined as a fair average for general experience. See Chapter V. Section 2.
Still another fact is apparent from a consideration of the last named formula. As the wires get stretched and crowded more and more into what may be called a permanent position, there will be less and less movement of the wires about each other upon the application of tension to the rope. Therefore as the rope grows older in use the value of E may be ex- pected to increase unless the per- manent set of the wires is inter- fered with by the bending of the rope around sheaves or drums. In general, then, when used on very large drums or sheaves the value of E tends to increase, while on small drums the opposite will be the case. Reduction in the value of
E may also be caused by gradual deterioration of the hemp centers, in wire ropes used for long periods.
In modern construction and min- ing work ropes of great length are very generally used, and the weight of the rope itself is a considerable item in the total load that the upper end of it has to carry. The upper end, then, must undergo a heavier stress than the lower end. The lower end, however, is subject to more severe impact stresses than the upper, since before raising a load, be it a bucket or skip or mine car, there is a slack to be taken up. This slack comes out with a jerk when the rope becomes taut, and develops an impact stress that is difficult to estimate. The jerk or impact is absorbed by the elasticity of the rope more and more in pro- portion as the impact wave travels away from the impact point. Therefore it is minimum at the top. We thus have the heaviest load stresses at the top and the heaviest impact stresses at the lower end, and for this reason it is the two ends rather than the middle that should be examined periodically for deterioration. Of the two the lower end is more dangerous than the upper, because the upper end is usually wound on a drum in a nice, warm, dry engine house, while the lower end is generally exposed to wet, hard knocks, twists and various other abuses. See Chapter V. Section 3.
In a solid bar of steel, such as a chord member in a bridge, the " straining" or elongation and
American Wire Rope
VI
shortening of the material is ac- companied by molecular motion of its particles. In a rope, besides this molecular motion of the par- ticles, there is a molar motion of the units, fibres or wires, com- prising the structure itself. The loss of power incidental to this molar motion can be very largely reduced by the use of internal lu- brication, which is a comparatively recent development in wire rope practice. The consequent reduc- tion of internal friction makes for a high mechanical efficiency of tackle, and eliminates a great deal of destructive effect of intermittent stresses on the rope itself. This is applicable to straight ropes that do not carry a quiescent load, but more particularly to all ropes that run over sheaves and drums. Ex- ternal lubrication, also, is valuable where the rope is subject to corro- sive action or mechanical attrition. Hemp rope deteriorates with age and with use. Wire rope deteri- orates with use, but not with age when properly cared for, and the rate of deterioration depends, among other things, on the follow- ing factors :
(1) Character of the metal.
(2) Arrangement of the wires.
(3) Ratio of the stresses to the
strength.
(4) Ratio of the maximum to the
minimum stress.
(5) Diameter of sheaves and
drums.
(6) Corrosive and abrasive ex-
ternal effects.
(7) Quality of lubrication, in-
ternal and external.
To guard against deterioration frequent inspections and occasional tests of the rope are important, particularly when the rope is used for handling men. In different European countries there are well defined rules for testing and in- specting and in this country many of the States have laws intended to guard against breakages in service. The practice here has not yet been satisfactorily standardized as between the different States. Although in a wire rope the pitch of the inside strands is not the same as that of the outside ones, the outside wires are more likely to break than the others on account of the greater bending stresses of drums, etc. The binding action of the twist, that in a wire rope is not accompanied by initial torsion, is such as to equalize and dis- tribute the strain on all the wires between the center and the cir- cumference in a way that is an- alogous to the action of the rein- forcing steel in a concrete beam. As a corollary to the above, ex- ternal inspection of a wire rope is much more to be depended upon than outside inspection of a hemp one. If the visible wires are sound it is altogether probable that the inside ones are, too. This fact should not, however, be taken as an excuse to neglect regular and careful tests.
A long rope, such as a mine hoisting cable, is subject to vibra- tions which become intensified at the load end, with the effect of causing a more rapid fatigue of the
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metal at the point of attachment to the car or skip than elsewhere. We therefore recommend cutting a few feet off of this end periodically and refastening the rope as before. By using in combination the qualities of flexibility and tensile strength, all the various contriv- ances of sheaves, pulleys and drums are applied for the transmission and multiplication of power. When a rope is bent against its own re- sistance, work is performed on it, and this work necessarily reduces the efficiency of the tackle. In ordinary manila tackle with blocks
of good quality, the mechanical efficiency of a six-ply rig, for ex- ample, is likely to be between seventy and eighty per cent, of the theoretical figure, the remaining power being dissipated in the friction of the blocks and the work done by bending and stretching the rope.
An important factor in the con- sideration of ropes is the efficiency of the various forms of knots and splices. For manila rope the fol- lowing results were obtained in tests at the Massachusetts Institute of Technology, viz.:
Efficiency of Knot
KIND OF KNOT
90%
80% 65% 60% 50%
45%
Eye splice over iron thimble.
Short splice in the rope.
Timber hitch, round turn, half hitch.
Bowling slip knot, clove hitch.
Square knot, weaver's knot, sheet bend.
Flemish loop, overhand knot.
These percentages are in terms of the full strength of the rope.
The mechanical applications of rope may be divided into the fol- lowing classes :
I. Static, such as guys, bridge cables, shrouds, etc.
II. Kinetic, such as power trans- mission lines, running ropes, tackles, etc.
In the static class there will be no bending stresses, except such as are incidental to the anchorages and splices. These by various mechanical contrivances are now capable of a very large percentage
of efficiency, in contrast to the knot factors of hemp rope men- tioned elsewhere in this chapter. For static use flexibility is no ob- ject, and the most satisfactory types of rope for this purpose are therefore the dense ones of few wires and long pitch, thus giving the smallest cost and greatest durability for the required strength. A form of static rope is that used for cable way main cables, wherein the rope acts as a monorail besides acting in static tension, and suffers attrition of the outer wires. Special twisting of the outer strands and
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such construction as the inter- locking wire rope are peculiarly adapted for such a purpose, since they combine economy of cost and weight with a comparatively smooth wearing surface. The span of the main cable in cableways often controls the kind of material that must be used in the wires of the cable. If the spans are reason- ably short the stresses in the cable from its own weight are small as compared with those from the load, and an ordinary steel wire of low price is suitable. Where the spans are long, however, and where, from the topography of the ground, the amount of allowable sag is limited, the stresses from the weight of the cable become very important and wire of a higher tensile strength and higher price must be used. A careful study of all the conditions, as well as an intimate knowledge of the various classes of rope on the market, is necessary in order to select the most economical one for the purpose. See page 53.
For kinetic uses a rope of con- siderable flexibility is necessary. Mine hoists, for deep working, generally have drums of fairly large diameter, and the load carried by the rope is very considerable, be- sides which the weight of the rope, when the car is at the bottom, is a large item. Therefore, for this purpose a strong high tension material is necessary, together with moderate flexibility. For use with derricks, cable way falls, elevators and hoists, where the loads are comparatively light, and where the
rope must run over sheaves of small diameter, flexibility becomes more important and high tensile strength per unit of weight less so. Hence for these purposes we need the hoisting ropes of small and numer- ous wires. There is a very large variety to choose from in selecting a rope for a specific purpose, and there can be only one kind that will be satisfactory for a particular purpose. Therefore, before order- ing any rope, the object that it is intended to fulfill as well as the characteristics of the rope should be thoroughly considered. When in doubt as to which of two ropes to select, it is better to take the chance of erring on the side of too much flexibility than on that of too little. The necessary strength will control the diameter, which can be taken from the tables in this volume. The effect of wear on a hoisting rope is most important. When used on a derrick such as in the construction of a bridge or high building, frequently the fall rope is used in a three-ply com- bination of sheaves, and where the fall rope is long the rope becomes twisted upon itself by the revolu- tion of the load. The raising and lowering of the load under these conditions, causing the ropes to rub each other while twisting about each other, is highly destructive of the rope.
In the foregoing pages the prin- cipal characteristics of the wire rope, and its antecedent, the hemp rope, have been given, and it is believed that a perusal of them
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will place the reader in possession of so many of the general facts and conditions of the rope problem, as may be necessary to a good general conception of it. A great deal more of general discussion might be written. There is already an ex- tensive literature on wire rope, and as a mechanical device it represents a large field of investigation not yet covered by the mathematician, the testing expert and the metal- lurgist. The effects of tension, tor- sion and attrition acting simultane- ously, complicated by temperature changes and the results of corro- sion, lubrication and, at times, electrolysis, offer problems at once fascinating and elusive. The fact that many of them are still un-
solved, however, does not detract from the certainty that as pro- duced in the mills of to-day, the wire rope is an appliance that is wonderfully well adapted to a mul- titude of uses, manifest and undis- covered, with a composition and a structure that can be varied almost endlessly to meet given conditions. It can be made with very great accuracy and reliability under proper service, and not least of its virtues is the fact that for the quan- tity of goods delivered it is far and away the most economical tool to be had for its purposes. The field of its use and its adaptability to various purposes have grown by leaps and bounds, and were never growing so fast as to-day.
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Ffg. I.
Fig. 2.
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Chapter I Standard Breaking Strengths of Wire Rope
The demand for accurate information regarding wire rope has led the various manufacturers of the United States to adopt standard figures for the strength of all sizes and qualities of rope. It was formerly the practice of most manufacturers and nearly all users of wire ropes to test the individual wires and to consider their combined strength as the strength of the finished rope. Strengths thus obtained were greater than actual strengths obtained by breaking the ropes as a whole. It was on this account that the standard strengths now given in this catalogue were adopted, all figures representing actual breaks. In no case was the intrinsic strength of the ropes reduced, but more accurate and scientific data are shown in the line of progress. With some constructions and qualities of rope, the strength given represents 95 per cent of the total strength of the wires taken singly, but in other cases with different constructions it may run down to 80 per cent or even less. The question which interests the user is whether a rope will stand when new the strain given in the tables, and we can state positively that our ropes will meet the strengths given herein if properly tested.
Method of Testing American Wire Rope
The testing of a wire rope is not a difficult matter, but it must be properly done or it is valueless. All finished wire used in our wire rope is given a rigid test on both ends of each coil to determine its strength, tough- ness and uniformity. No coil of wire that fails to meet the rigid tests is used in American wire rope. We have not only the latest and best methods of wire testing, but we have the most improved machinery capable of testing to rupture any wire rope shown in this catalogue. Tests are constantly being made of finished ropes to assure their adherence to the standard strengths given in the tables.
The strengths given are correct only for our standard product of the construction shown, it being obvious that any variation or modification of the standards would somewhat alter the strength of the rope. We have figures for these modified constructions and qualities and can furnish them when required.
These testing facilities are complete from a machine for the smallest wire to one for the largest rope listed herein, so that customers may rely absolutely on the information given.
American Wire Rope 11
Chapter II Material in Wire Rope
Wire ropes are made almost exclusively from iron or steel and there have been applied to the various grades of strength of materials certain names which have clung to them until they can hardly be dispensed with. To many perhaps these terms have been more or less misleading or confusing. It is our intention to set this subject briefly »before the trade so that there may be a clear understanding of the various trade names used in this catalogue.
The materials used in the wire ropes as described in the succeeding pages are grouped into five main divisions as follows :
1. Iron.
2. Crucible Cast Steel
3. Extra Strong Crucible Cast Steel
4. Plow Steel
5. Monitor, or Improved Plow Steel and Tico Special
6. Hemp Centers.
First : IRON — This material was used almost entirely in the early days of rope manufacture and is employed to a limited extent at the present day, although by no means so extensively, owing to the development of the stronger and tougher steels. Iron is a very pure material containing very small amounts of phosphorus, sulphur and carbon. The physical characteris- tics of iron are softness, ductility and low tensile strength, being approximately 85,000 pounds per square inch in the drawn wire entering into ropes. This applies to the iron transmission and hoisting rope illustrated on pages 121 and 127. Purchasers of our bright iron rope are assured that it contains the best material that can be produced.
Second: CRUCIBLE CAST STEEL — This brand of steel derived its name from the early method of making carbon steel which could be hardened. This was formerly made in small crucibles capable of being operated by hand and containing from 50 to 100 pounds of steel each. This steel was then cast into small ingots or bars. The same grade of steel for rope is now universally made, both in Europe and America by the Siemens-Martin open hearth furnace, which differs from the original crucible principally in size and amount which can be made at one time. With the old crucible process, each small ingot was of different chemical composition, but with the open hearth furnace, the larger units of steel are of the same chemical composition and each batch from the Siemens-Martin furnace will make a number of large castings or ingots.
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When drawn into wire and properly treated, our crucible open hearth steel* will have a tensile strength from 150,000 to 200,000 pounds per square inch of sectional area, depending upon the size of finished wire and the properties required.
Third: EXTRA STRONG CRUCIBLE CAST STEEL — This, as its name indicates, is a stronger grade of crucible open hearth steel of somewhat different chemical composition, the strength of which runs from 180,000 to 220,000 pounds per square inch of sectional area, depending upon the size of finished wire and properties required.
Fourth: PLOW STEEL — This name originated in England many years ago, and was applie/i to a strong grade of crucible steel wire which was used in the construction of very strong ropes employed to operate gangs of plows.
The name of " plow steel," as applied to rope, means a high grade open hearth steel of a tensile strength in the wire of 200,000 to 260,000 pounds per square inch of sectional area, depending upon the size of the finished wire and the properties required. The name, although somewhat vague and unsatis- factory, has been associated with the trade for a long time.
Eifth: MONITOR, OR IMPROVED PLOW STEEL AND Tico SPECIAL — We have adopted the trade names of " Monitor" and "Tico Special" for the strongest grades of wire rope which we produce. ~ These are made of very carefully selected open hearth steel wire having a tensile strength from 220,000 to 280,000 pounds per square inch of sectional area, depending upon the size of the finished wire used in the rope. These are the toughest materials of high strength that have yet been produced. They have a large and constantly growing field of use.
Sixth : Hemp centers are usually employed in wire ropes to form an elastic cushion for the strands of the rope to rest upon. These are selected with great care and only the finest and most uniform fiber is used.
The merits of these various grades of materials may be summarized briefly.
Iron This is a low tensile strength material, very soft and ductile, but the heaviest in proportion to its strength and consequently of only limited usefulness.
Crucible Cast Steel This is a medium tensile strength material, tough and pliable, of moderate cost and general utility. It weighs
only about one-half as much as iron for the same strength and its lightness makes it very efficient. It is harder than iron and better resists external wear.
term open hearth steel must not be confused with crucible open hearth steel, as the latter applies only to the higher grade of material of crucible quality, whereas the former may mean any grade of steel produced by the open hearth furnace.
American Wire Rope 13
Extra Strong Crucible Cast Steel This is a grade midway between crucible
steel and plow steel in tensile strength,
and is a very serviceable material, tough, pliable, a little lighter for the same strength than crucible steel, and about two and a half times the strength of iron.
Plow Steel This is next to the strongest material used in wire rope, combin- ing lightness and great strength. It is tough, but somewhat stiffer than crucible steel, and possesses very nearly three times the strength of iron.
Monitor, or Improved Plow Steel This is a little stiffer in the same diameter
than the preceding kinds, but strength
for strength equally flexible. It is very useful where great strength, lightness and abrasive resisting qualities are required. It is the toughest steel of its strength that can be produced, and is fully three times as strong as iron.
Tico Special Steel This special grade of steel wire is used in the manu- facture of Tico special ropes, which possess the highest
degree of resilience and strength possible without sacrificing the inherent elasticity of the material. For list prices, see Monitor rope.
The manufacture of these various grades of steel is an art in itself, which has been perfected after a half of a century of effort to its present high standard by the American Steel & Wire Company. Consumers mnv be assured that the materials used to-day in rope manufacture are more reliable tharv at any time in the past. The selection of ingredients going into the production of our rope steels is more carefully and scientifically handled and the resulting product more uniform than has hitherto been deemed possible.
It will be found that the materials entering into American wire rope contain the smallest possible amounts of phosphorus and sulphur, the delete- rious effects of which are well known. Every heat of rope steel made is carefully analyzed and checked, and only such as conforms to our rigid chemical tests is ever used for wire rope. The same watchful supervision is given every process in the manufacture of the wire for the finished rope. The steel must be cast into ingots, rolled into billets, re-rolled from billets to small bars and then into rods before it reaches the wire-drawing stage. These rods must then be cleaned, drawn, given successive heat treatments and further drawing until the wire has been brought to the finished point. If at any of these stages the material shows mechanical defects, however slight, it is rejected, and every coil of the finished wire is given further exacting tests, all to determine its quality, which is the keynote in the production of American wire rope.
14
American Steel and Wire Company
Chapter III
Constructions
In the development and application of wire rope there have been devised many constructions, some good and some bad, but in course of time odd com- binations of wires have been discarded and certain types have become standard. These standard constructions constitute the greater percentage of the wire rope ordinarily used in commercial work to-day.
Wire rope as now produced consists of a group of strands the wires of which are twisted together symmetrically according to a definite geometrical arrangement. A group of strands is correspondingly laid symmetrically around a center core or neutral axis.
Strands
The fundamental unit in rope construction is the strand, and a short explanation of this is necessary to place the subject logically before rope users. To begin with, a vast number of geometrical combinations of wires are possi- ble, but for ordinary work the practice is to use one wire in the center of the strand, surrounding this with a layer of six wires, then successively with layers of twelve, eighteen, twenty -four and thirty wires, etc., this construction being known as concentric strand.
12
18
24
30
. 1 Wire
Wij
19 Wires
37 Wires
61 Wire.
91 Wires
The addition of one layer of six wires around a center wire produces a strand for a haulage rope. A supplementary layer of twelve wires makes a nineteen-wire strand for a hoisting rope. This strand in turn may be covered by a third layer of eighteen wires, making a thirty-seven-wire strand that is used in a special flexible hoisting rope. In connection with illustrations of strands of uniform diameter it is evident that the greater the number of wires in the strand, the more flexible will be the rope constructed therefrom.
American Wire Rope
15
7 Wire Strand
19 Wire Strand
37 Wire Strand
6 1 Wire Strand
91 Wire St
16 American Steel and Wire Company
In the making of standard hoisting ropes, i. e., of six strands of nineteen wires each, certain desirable features result from a slight modification of the strands and wires :
1. Common one-size-unre construction, nineteen wires all of one size, is the simplest hoisting rope strand made.
2. Three-size-wire construction, sometimes called " Warrington" con- struction, consists of seven inside wires of uniform diameter surrounded by twelve wires which are alternately large and small. This combination increases the metallic area and strength by approximately ten per cent. Experience has demonstrated the advantages of this construction for general hoisting purposes and has led to its adoption in the manufacture of standard steel hoisting ropes.
3. Seale construction, in which the center wire is large, the next layer of nine wires small and the outer layer of nine wires large. These strands produce a rope somewhat stiffer than the first two mentioned. See further reference to Seale construction.
It is possible to make strands using two, three, four or five wires in place of one center wire, and to cover these wires with successive layers of wires, but these constructions are rarely used and have little commercial value. There are a few cases where odd constructions are advisable, and we shall be glad to give our customers any information necessary upon application.
The types of concentric strand shown in the preceding illustrations are compact, present a uniform external surface to take wear and give a wide range of flexibility.
Rope
A number of strands, usually six, are laid together around a hemp center to form a completed rope. In the order of their flexibility from coarse to fine constructions they are
6 strands, 7 wires each, known as " haulage rope "
6 strands, 19 wires each, known as hoisting rope, "Seale type"
6 strands, 19 wires each, known as "hoisting rope"
6 strands, 37 wires each, known as " special flexible "
8 strands, 19 wires each, known as " extra flexible rope"
6 strands, 12 wires each, known as " running rope"
6 ropes, 6 strands, 7 wires each, known as " tiller or hand rope"
In describing a rope construction it is customary to use the following abbreviated notation, e. g. 6 x 7, which means six strands of seven wires each, the number of strands coming and the first number of wires last.
American Wire Rope
17
Haulage, Transmission and Standing Rope Construction
The coarsest rope, i. e., the 6x7 construction, is a relatively stiff rope with large wires capable of resisting external wear or abrasion, but it is the least flexible type shown and its use is limited to conditions where abrasion is excessive and bending around sheaves is a minor feature. See chapter on "Practical Applications," page 72.
Scale Construction
The next rope in point of flexibility is the 6 x 12 with one hemp core (each strand composed of three wires covered by nine wires), or better still the 6 x 19 Scale type. The use of the 6 x 12 construction is not recommended, as it mak^s a poor rope structurally, and the 6 x 19 Seale type is not only identical so far as external surface of the strand goes, but is properly constructed internally. The name " Seale type construction" is applied to a rope each strand of which is composed of one large center wire surrounded by nine small
IS
American Steel and Wire Company
wires and then by nine large wires, making a perfect mechanical construction. The Scale type is suited to a limited number of applications and is sold at the same price as the regular 6 x 19 construction.
Hoisting Rope Construction
The next step toward flexibility is the 6 x 19 construction, known universally as hoisting rope, due to its application to general hoisting purposes. The wires are smaller than in the 6x7 haulage rope and are less able to resist abrasion, but can be more easily bent around sheaves and drums.
Special Flexible Hoisting Rope Construction
The 6 x 37 special flexible rope is composed of still smaller wires than the 6 x 19, possesses great flexibility and may be bent round fairly small sheaves, but it should not be subjected to much external wear, particularly in the smaller sizes, as the wires will be worn off too quickly.
American Wire Rope
19
Extra Flexible Hoisting Rope
The 8 x 19 extra flexible rope has more flexibility than the 6x19, being composed of two additional strands, and may be used over smaller sheaves than the latter. It is about as flexible as the 6 x 37 construction but not as strong, owing to its larger hemp center.
Running Rigging Construction and Mooring Hawsers
The 6 x 12 running rope is a modification of the 6 x 19 construction, being identical so far as external appearance goes, having a hemp core in each strand or seven in all. This type of construction is more flexible than the 6 x 19 but only about two-thirds as strong.
20
American Steel arid Wire Company
Tiller Rope Construction
The 6x6x7 tiller rope construction makes an exceedingly flexible rope, and is capable of bending around very small sheaves. It is the most flexible standard rope on the market to-day. Being composed of very fine wires it will stand less surface wear than any type mentioned and the load should be light.
Special Constructions
In addition to the preceding constructions there are a number of special constructions which have been developed to meet unusual conditions. The particular qualifications of each are referred to in the following pages.
Non-spinning Rope, 18 Strands 7 Wires
This is a special construction of hoisting rope designed to prevent the rotating of a free load on the end of a single line. It is the only type of rope that really does accomplish this and is excellent for the purpose for which it is designed.
American Wire Rope
21
Flattened Strand Hopes, Hoisting and Haulage
Type A
Type B
Type C
Type D
22
American Steel and Wire Company
Type E
These five styles of flattened strand have been designed to secure greater wearing surface and at the same time to retain as much flexibility as possible. It will be easily seen from an examination of the illustrations that these ropes more nearly approach a solid bar so far as external surface is concerned than is possible in the case of any style of rope made of round strands. In fact, flattened strand ropes possess about 150 per cent more wearing surface than the ordinary round strand rope. This is a distinct advantage for some wire rope applications where external wear on the wires results in a considerable decrease in strength as well as shorter life of the rope.
Types C (5 x 9), D (6 x 8), and E (5 xll) correspond in general to the 6x7 round rope, and types A (5 x 28) and B (6 x 25) to the 6x19 construc- tion in the general line of flexibility and usage. Their further uses are explained in detail under the various lists, pages 145 to 154.
Steel Clad Hoisting Rope
This kind of hoisting rope has each strand spirally served with flat steel strips, which give considerable additional wearing surface over the ordinary type. In fact, when the flat strips of a steel clad rope have worn through, there still remains a complete hoisting rope with unimpaired strength, Where ropes wear out quickly, this feature is a distinct advantage.
American
Rope
Flat Rope
This rope corresponds to a flat wire or ribbon and might be likened to a flat clock spring in this respect, that it will wind upon itself in a very narrow space. Some conditions are eminently suited to this type of construction, which can be made in any reasonable width, thickness or length. Further information regarding uses will be found on page 194.
American Steel and W^ire Company
Round Track Cable for Aerial Tramways
Locked Wire Cable
For cable spans or cableways there have been devised two special cables which present fairly smooth surfaces for wheels to run upon. The better is the interlocked type, as it presents the smoother external surface. See also pages 190-191 for further details.
A point that should be noted in the foregoing discussion of wire rope constructions is that in going from a coarser to the next finer construction, or with each increase in flexibility, there is a corresponding decrease in the size of the wires and consequently in the wear resisting qualities. This should be borne carefully in mind in the selection of the type of wire rope to be used for a given application. In this connection a further discussion of this subject is found in the chapter on " How to Calculate Wire Rope Prob- lems," on pages 30-66.
American Wire Rope
Wire Rope Lays
There are two general methods of laying up rope : the common type known as Regular lay, and the other as Lang's lay.
Regular lay, right hand rope, 6x 19
lay, 6x7
In the Regular /ay, the wires of the strands are twisted in one direction and the strands laid into the rope in the opposite direction, giving the appear- ance shown in the first illustration. Most of the rope used in America is made in this manner, and it has become standard for general work.
In the Lang's lay rope both the wires in the strands and the strands in the rope are twisted in the same direction, giving the peculiar appearance noted in the second cut. Lang's Jay rope is more easily untwisted than Regular lay and it is more difficult to tuck the strands securely in a splice, but it is especially adapted to resist external wear and grip action. Lang's lay rope should not be used without first consulting with us as to its adaptability. No universal rule can be given regarding its application, other than that its use is limited as compared with the standard Regular lay.
It will be noted that all flattened strand ropes are made IJang'ls lay. See illustrations on preceding pages 21 and 22.
26
American Steel and Wire Company
Regular lay, right hand rope
Regular lay, left hand rope
Rope is usually made right lay, which is standard for all our rope as well as that of all other manufacturers in the United States. Right lay rope corresponds to a right hand threaded screw of long pitch and left lay to a left hand threaded screw of long pitch. The use of left lay rope is limited and confined to rope used in pairs on elevators and similar places where the tendency of left lay rope to untwist in one direction is offset by the tendency of the right lay rope to untwist in the opposite direction. The majority of oil well drilling ropes are also made left lay.
Reverse lay rope, also known as right and left lay rope
This consists of a rope in which the alternate strands are made Regular and Lang's lay. In the case of a six-strand hoisting rope, as shown, there are three strands regular lay and three strands Lang's lay. Not many ropes are made in this way, but this description would be incomplete without reference to it.
American Wire Rope 27
Chapter IV
Range of Application
The use of wire rope for mechanical purposes has increased very largely in the past few years, so that it has almost completely superseded the older methods employing manila rope and steel or iron chain.
The scope of application has become universal, involving the selection or at times the designing of a special rope to meet the conditions imposed. It sometimes necessitates a radical departure from the ordinary forms of construction. With the facilities and plants at our. command, we can try out rope for every class of service and give our customers not an experiment, but a proven rope. We make a complete line of wire rope for every practical purpose to which a wire rope can be applied. Some of the principal uses to which wire rope may be put are as follows: Haulage rope for mines, docks, etc.
Hoisting rope for elevators of * all kinds, mines, coal hoists, ore hoists, conveyors, derricks, stump pullers, steam shovels, dredges, logging, ballast, unloaders, etc. Special flexible and extra flexible rope for cranes, counterweights,
ammunition hoists, dredges and kindred uses. Flattened strand rope of all kinds for all purposes. Track cable for aerial cableways, both ordinary and locked types. All the foregoing ropes except the interlocked track strand are made in all strengths of material, viz. : Iron.
Crucible Cast Steel. Extra Strong Crucible Cast Steel.
Plow Steel and Monitor grades and may be furnished galvan- ized if necessary. The following additional ropes are also made :
Extra Galvanized Standing Rope for derricks, ships' rigging, etc. Extra Galvanized Hoisting and Running Rope for mooring and
messenger lines, cargo hoists, ships' rigging, etc. Extra Galvanized Hawsers for mooring and towing. Galvanized Cables for suspension bridges.
Wire Sash Cord, annealed, galvanized or tinned, iron or copper. Galvanized Mast Arm or Arc Light Rope. Galvanized and Extra Galvanized Strand in all sizes. Special Ropes of every size, construction or quality made to order on short notice. If it is rope or stranded wire we make it. All sizes of copper cable and strand for all electrical pur- poses. Also fittings of all kinds for attaching to wire rope.
American Steel and Wire Company
In the general definition of wire rope is included practically everything that is twisted into strands or ropes. Even wire sash cord -^ inch in diameter is a rope just as truly as a large dredge rope 2^ inches diameter and a small tiller or hand rope as much as a large mine hoisting rope. A small aeroplane stay strand differs from a large bridge cable only in size ; both are stranded products. It is difficult to give all the various uses to which v/ire rope can be put, but -from very small to very large sizes they cover a wide range of utility. Almost any special type of construction may be made if required by the conditions of use.
It will be seen from the foregoing summary that wire rope in its vari- ous sizes is adaptable to the most delicate mechanisms, as well as to the handling of the heaviest and largest machinery. Its adaptability is one of its strongest merits.
See also chapter on practical wire rope installations pages 72 to 118.
Chapter V
How to Calculate Wire Rope Problems
30 American Steel and Wire Company
Chapter V
How to Decide Size, Quality and Construction of
Wire Rope
In discussing this important question, around which hinges the successful use of wire rope, we will consider it under two general headings.
A. — STRESSES.
B. — SIZES AND QUALITY OF ROPE TO MEET THE STRESSES.
Under Stresses, the following detail sections will be taken up in the order given :
Page
1. Dead and live loads ...... 30
2. Bending stresses . . . . .• . . 31
3. Stresses due to shocks of starting and stopping . 47
4. Stresses of inclines and slopes . . . . . 49
5. Stresses in spans . ... 53
6. Stress limitations of machinery .... 58
7. Multiple sheave blocks ...... 58
8. Wire rope guys ....... 60
9. Factors of safety ....... 64
The above nine sections constitute the principal factors requiring con- sideration in wire rope operations.
A. — Stresses
Section 1
Dead and Live Loads Wire rope applications divide themselves into two
general classes, one in which the load is stationary
and the other in which it is movable or fluctuating. It is a comparatively easy matter to estimate the stresses in a rope when the loads are what might be termed dead loads, such as occur in guy ropes and similar uses. On the other hand, a live load immediately brings us to a point where a number of factors must be carefully considered. The principal factor of course is the changing of motion of the load. All loads are dead loads until they begin to move and then they become live loads. The effect of a live load at times is not very greatly different from that of a dead load, provided the stress induced is uniform, but there are many cases where the load is started and stopped quickly and such cases result in a series of stresses due to shocks of start- ing and stopping. Stresses due to shocks of starting and stopping will be considered under Section 3, of this chapter.
American Wire Rope
31
Section 2
Bending Stress on Wire Rope The subject of this section is not a new
one by any means, but it has been regarded
by many wire rope users as of no practical importance. This view of the case is erroneous, and we shall endeavor to show that it is not only im- portant, but neglect of consideration often leads to very poorly designed apparatus and subsequently high maintenance charges, discouraging both to the user as well as to the builder. The user often finds his maintenance charges excessive, and it is difficult at times for him to understand clearly that his rope conditions are at fault.
SOLID BAR
ROPE SENT AROUND DRUM
The bending stress in a wire rope, as we define it, is the stress which is produced in the metal composing it when the rope is bent around a sheave or drum of any diameter. Unlike ordinary stresses it does not appeal to the eye of the rope user in the same way that a live or dead load does, but it exists to a greater or lesser degree in all wire rope applications. It takes its toll, whether it is recognized or not, and while it is not possible to eradicate it entirely, still when its value is known its deleterious action can be reduced to a minimum, provided sheaves and drums are made proper size. It is serious to neglect consideration of any of the stresses effecting a rope, no matter how produced, because the success or failure of such appliances centers around these points.
It is not surprising perhaps that many rope users and even some engineers have avoided this subject, because it is a fact that a good deal of the information now extant upon the subject contains just enough of truth to
American Steel and Wire Company
be deceiving. This is because after an elaborate mathematical process one wrong assumption has been made which nullifies completely the results obtained. In the present chapter we have availed ourselves of data gleaned from practical experiments, covering a considerable period of time, and numerous tests, so that the information given may be taken at face value. l%
If we attempt to bend a bar of iron or steel one inch in diameter around a sheave or drum three feet in diameter we would find that the material had been stressed beyond the elastic limit, or, in other words, it had stretched permanently. On the other hand, if a wire rope one inch in diameter were taken in the same way it would be found that it not only bent more easily but that it had little, if any, permanent set. The rope, however, has been stressed, although to a lesser degree. In fact, if it were a 6 x 19 rope it would have a stress of 20,000 pounds per square inch, or multiplying by the area of the wire in the rope, we have 3 . 72 tons. The stress in the iron bar would be approximately 800,000 pounds per square inch, according to standard formulae. This figure looks absurd, but it shows about forty times as much stress in the round bar as in a hoisting rope of the same diameter bent around sheaves of identical diameter.
Of course, long before the stress reached 800,000 pounds per square inch in the round bar, the material composing the bar would have begun to stretch as it would in the case of steel when the stress reached about 30,000 pounds per square inch. If it were possible to make material with an elastic limit of 800.000 pounds, the round bar would have that stress when bent around a 3-foot sheave.
The formula usually used for calculating the stress in a solid bar bent around a sheave is given in most books on mechanics as follows :
where S = stress per square inch in material due to bending E = Youngs modulus = 29,000,000 for steel d = diameter of bar D = diameter of bend
It has been the practice of some engineers to calculate the bending stress on a rope by means of the above formula (1) modifying it by taking
d = diameter of wire in the rope.
This would be correct if a wire rope were composed of straight wires, but it is decidedly incorrect because of the fact that the wires of a rope are twisted, and the stress very much different. This is the principal point of the entire problem.
American Wire Rope
The twisting of the wires spirally in a rope has the effect of reducing the stress materially over that in a round bar.
The keynote of the problem lies in taking the right modulus of elasticity, this fact being apparent when this subject is investigated, and it is this practical point which has been the stumbling block to many theoretical calcu- lators. We have determined by careful tests that the modulus of elasticity for ordinary wire ropes with a hemp center does not exceed 12,000,000 pounds when the rope is new, and we have used this figure in the calculation of the tables given on the following pages. The formula used to make these calculations is
S-E ^D
where EK = modulus of elasticity of the whole rope value = 12,000,000
pounds for six-strand ropes d = diameter of wire in the rope
D = diameter of sheave to center of the rope or neutral axis S = stress per square inch in wires of rope due to bending around sheave of diameter D
The values obtained which have been tabulated on the following pages are reasonable, accurate and applicable to the calculation of all rope problems. They show the stress in a wire rope from the smallest to the largest practicable sheave that is used for any work, and we ask the careful consideration of them by all rope users.
For the purpose of getting a line of uniform stress in a wire rope we have drawn zigzag diagonal lines which show the stresses in tons for a uniform stress per square inch, which will be valuable in indicating whether the sheaves and drums in a wire rope system are properly proportioned.
In general the bending stress should be kept at as low a value as possible. This varies with the class of work or nature of application; values that would be considered high in mine work would be low for some classes of machinery, because in the latter case it may be necessary to sacrifice the life of the rope for the sake of greater economy in other respects. We do not believe in sacri- ficing the rope service until other means of successful solution of a problem have been carefully considered, because in the long run such propositions are usually expensive and unsatisfactory to the owner, and oftentimes present a difficulty that at best can only be partially solved by the rope manufacturer.
It would hardly be advisable to use as large sheaves on a hand crane or machine operated only intermittently as on an apparatus that is constantly working. The effect of the bending stress is shown usually in the decreased life of a rope.
34 A merit mi Steel and Wire Company
The practical application of the following tables is best shown by an example solved in accordance with this rule :
1. Divide the breaking strength of the rope as given under the tables of strength by the factor of safety which it is desired to use. From this quantity deduct the bending stress for the diameter of rope and size of sheave or drum under consideration, and the result will be the proper working load.
e. g. What load will a ^s-rope carry with a factor of safety of 5 over a 3-foot sheave?
Catalogue strength of S/8 plow = 15.5 tons (6x19 Rope)
Divide by 5 = 3.1 tons
Deduct bending stress . . . = 0.91 ton
Proper working load . . . = 2.19 tons
which means that the working load is 2.19 tons after considering the bending stress. It must be noted in particular that the bending stress must not be deducted from the total strength of the rope, but only after the factor of safety has been applied.
The total load on the rope is 3.1 tons, of which 2.19 tons is useful load and 0.91 ton is non-utilizable load or bending stress.
It is only necessary to consider in any problem the minimum size of sheave because the maximum stress is produced by the smallest sheave, and the passing over more than one sheave does not alter the bending stress, although the greater the number of sheaves the greater will be the surface wear upon the rope. It is also true that the fewer the sheaves used in any wire rope system the longer the rope will last.
American Wire Rope
35
Bending Stress for Different Sizes of Sheaves and Drums
For 6x7 Rope in Net Tons
|
Diatn.o Rope in Inches |
Diameter of Sheave or Drum in Feet and Inches |
|||||||||
|
15'-0' |
14'-0' |
13'-0" |
12'-0" |
ll'-O' |
lO'-O* |
9'-6' |
9'-0' |
8'-6" |
8'-0' |
|
|
1# 1# IX 1# 1 |
5.04 |
5.40 4.16 |
5.82 4.48 |
6.30 |
6.87 5.29 |
7.56 |
7.96 |
8.40 6 47 |
8.89 6 85 5.14 |
9.45 7.27 5.46 |
|
3.88 1 2.91 |
4.85 8JJ4 |
5.82 4 37 |
6.13 1 4.60 j |
|||||||
|
3.12 2.24 |
3.36 2.42 |
3.97 2.86 |
4.86 L 3 49 |
|||||||
|
2. 01) 1.49 |
2.62 1.87 |
3.14 2.24 |
3.31^ 2.36 |
3.69 |
3.92 2.80 |
|||||
|
1.60 |
1.72 |
2.04 |
2.49 |
2.64 |
||||||
|
jfe % # A # |
1.03 0.63 |
1.11 0.67 |
1.19 |
1.29 |
1.41 |
1.55 |
1.63 |
1.72 |
1 82 |
1.94 |
|
0.72 0.42 |
0.78 0.46 |
0.85 |
0.94 |
0.99 0.58 |
L 1.04 |
1.11 |
1.18 |
|||
|
0.37 0.26 |
0.39 0.28 |
0.50 0.36 |
0.55 0.39 0.28 |
0.61 |
0.65 , 0.46 |
0.69 0.49 |
||||
|
0.30 L.0.22 |
0.33 0.23 |
0.41 0 29 |
0.43 0 31 |
|||||||
|
0.19 |
0.20 |
0 25 |
0 33 |
0 35 |
||||||
|
A |
0.13 |
0.14 |
0.15 0.09 |
0.16 |
0.18 |
0.19 0.12 |
0.20 0.13 |
0.21 |
0.23 |
0 24 |
|
H A A |
0.08 0.04 |
0.09 0.05 |
0.10 |
0.11 0.06 |
0.13 |
0.14 0.08 |
0.15 0.09 |
|||
|
0.05 0.04 |
0.06 0.04 |
0.07 |
0.07 0.05 |
0.08 ' |
||||||
|
0.03 |
0.04 |
0 04 |
0.05 |
0.06 |
0.06 |
0.06 |
||||
For 6x7 Rope in Net Tons
|
Diam. of Rope in Inches |
Diameter of Sheave or Drum in Feet and Inches |
|||||||||
|
7'-V |
7MT |
6'-6" |
6'-0" |
5'-6" |
5'-0" |
4'-6" |
4'-0" |
3'-6" |
3'-8' |
|
|
1# iKs IX l# 1 |
10.08 |
10.80 8.32 |
11.64 8.96 |
12.60 |
13.74 10.58 |
15.12 |
16.80 13.94 |
18.90 14.54 10.92 |
8.96 |
6.88 |
|
7.761 5.82 |
9.70 1 L 7.28 |
11.641 8.74 |
||||||||
|
6.24 |
6.72 4.84 |
7.941 5.72 |
9.72 6.98 |
|||||||
|
4.18 2.98 |
4.48 3.20 |
5.24 L 3.74 1 |
6.28 1 4.48 |
7.84 5.60 |
||||||
|
3.44 |
4.08 |
4.98 |
6.40 |
|||||||
|
H X & A %_ |
2.06 1.26 |
2.22 1.34 |
2.38 |
2.58 |
[ 2.82 |
3.10 |
3.44 |
3.88 |
4.49 |
4.76 2.88 |
|
1.44 0.84 |
1.56 0.92 |
L 1.70 |
1.88 |
2.08 |
2.36 |
2.68 1 |
||||
|
0.74 0.52 |
0.78 0.56 |
1.00 0.72 |
1.10 0.78 0.56 |
1.22 i |
1.38 L 0.98 |
1.56 |
1.68 |
|||
|
0.66 L 0.43 |
0.66 0.46 |
0.86 O.C2 |
1.12 L 0.80 |
1.20 |
||||||
|
0.38 |
0.40 |
0.50 |
0.70 |
0.86 |
||||||
|
i TS H A A |
0.26 |
0.28 |
0.30 0.18 |
0.32 |
0.36 |
0.38 0.24 |
0.43 |
0.48 |
0.56 0.34 |
0.60 |
|
0.16 0.09 |
0.17 0.10 |
0.20 |
0.22 [ 0.12 |
0.26 |
0.30^ L 0.18 |
0.36 0.21 |
||||
|
0.10 0.08 |
0.12 0.08 |
0.14 0.10 |
0.16^ 0.11 |
0.20 ' 0.14 |
||||||
|
0.06 |
0.07 |
0.09 |
0.12 |
0.15 |
||||||
36
American Steel and Wire Company
Bending Stress for Different Sizes of Sheaves and Drums
For 6x7 Rope in Net Tons
|
Diam.ol Rope in Inches |
Diameter of Sheave or Drum in Feet and Inches |
|||||||||
|
3'-0" |
2'-9" |
2'-0" |
3'-3" |
2'-0" |
IMP |
l'-G" |
l'-3" |
r-0" |
||
|
IK 1H 1* l# i |
7.48 |
• |
||||||||
|
# H # 9 1? # |
5.16 8.12 |
5.64 |
6.20 |
4.16 |
4.72 |
3.12 |
[ 2.64 |
|||
|
3.40 |
3.76 2.20 |
|||||||||
|
1.84 1.32 |
2.00 1.44 1.00 |
2.44 1.72 |
2.76 1.96 1.40 |
|||||||
|
1.56 1.12 |
2.24 1.60 |
|||||||||
|
0.92 |
1.24 |
1.84 |
||||||||
|
rV Ks T6* A |
0.64 |
0.70 |
0.76 |
0.86 |
0.96 0.59 |
1.12 |
1.28 0.79 |
|||
|
0.40 0.23 |
0.43 ' 0.24 0.18 |
^J).47 |
0.52 |
0.68 0.39 |
||||||
|
0.28 0.20 |
0.31 0.22 |
0.35 |
0.47 [ 0.33 |
|||||||
|
0.16 |
0.24 |
0.28 |
||||||||
American Wire Rope
37
Bending Stress for Different Sizes of Sheaves and Drums
For 6x 19 Rope in Net Tons
|
Diam. of Rope in Inches |
Diameter of Sheave or Drum in Feet and Inches |
|||||||||
|
20'-0' |
18'-0' |
16'-0" |
15'-0" |
14'-0" |
13'-0" |
12MT |
ll'-O" |
lO'-O* |
y-6" |
|
|
2# 2^ 2X 2 1M |
11.63 |
12.92 9.71 |
14.54 |
15.51 11.65 |
16.47 12.48 |
17.89 |
19.39 14.57 |
21.15 15.89 |
23.26 |
24.50 18.40 |
|
8.74 1 6.37 |
10.92 1 7.96 |
13.45 9.81 |
17.48 1 12.74 |
|||||||
|
7.08 1 4.98 |
8.49 5.97 |
9.10] 6.40 |
10.61 7.47 |
11.58 1 8.15 |
13.41 9.43 |
|||||
|
4.481 3.00 |
5.60 3.74 |
6.89 1 4.61 |
8.96^ 5.99 |
|||||||
|
3.33] |
3.99 |
4.28 |
4.99 |
5.45 |
6.31 |
|||||
|
i# iK i# iX 15* |
2.40 1.88 |
2.67 |
3.001 2.36 |
3.20 |
3.43 |
3.69 2.90 |
4.00 |
4.36 3.43 |
4.801 3.77 2.91 |
5.05 |
|
2.09 1 1.62 |
2.51 1.94 |
2.69 1 2.08 |
3.14 1 2.42 |
3.97 3.06 2.30 |
||||||
|
1.46 1.09 |
1.82 1.36 |
2.24 1 1.68 |
2.65] 1.98 |
|||||||
|
1.21 0.88 |
1.45 1.06 |
1.56 1 1.14 |
1.82 1 1.33 |
2.18] 1.59 |
||||||
|
0.80 ' |
0.99 |
1.22 |
1.45 |
1.68 |
||||||
|
i H H H A |
0.56 |
0.62 0.42 |
0.70 |
0.75 |
0.80 0.54 |
0.86 |
0.93 L 0.63 |
1.01 |
1.12 0.75 |
1.18 0.79 |
|
0.37' |
0.47 |
0.50' |
0.58 |
0.68 , |
||||||
|
0.37" 0.21 |
0.40 |
0.43' |
0.47 |
0.50 |
||||||
|
0.23 |
0.25^ 0.19 |
L 0.27 |
0.29 |
|||||||
|
0.20 |
0.21 |
|||||||||
|
# rV H T5* « |
0.13 |
0.14 |
0.15 |
For 6 x 19 Rope in Net Tons
|
Diam. of Rope in Inches |
Diameter of Sheave or Drum in Feet and Inches |
|||||||||
|
9'-0" |
8'-G- |
8'-0" |
7'-G" |
7'-cr |
G'-6" |
G'-O" |
5'-6" |
5MT |
4'-6" |
|
|
2# 2K 2X 2 IK |
25.84 |
27.36 |
29.08 [21.84 |
31.02 |
32.94 |
35.78 26.90 |
38.78 |
42.29 31.78 |
46.52 34.96 25.48 |
28.32 19.92 |
|
19.48 L 14.16 |
20.56 14.99 |
23.30 ( 16.98 |
24.96 18.20 |
29.141 21.22 |
||||||
|
15.92 11.20 |
19.62 13.78 |
23.16 16.29 |
||||||||
|
9.96 [ 6.66 |
10.55 7.05 |
11.94 7.98 |
12.801 8.56 |
14.94 |
17.92 |
|||||
|
7.48' |
9.22 |
9.981 |
10.88 |
11.98 |
13.32 |
|||||
|
\H W i# ix \y% |
5.34' L 4.18 |
5.65 |
6.00 |
6.40 5.02 |
6.86 1 5.38 4.16 |
7.38 |
8.00 6.28 |
8.73 6.85 5.29 |
9.60 |
10.68 [ 8.36 |
|
4.44 3.42 |
4.72 3.64 |
5.80 4.48 3.36 |
7.54 5.82 4.36 |
|||||||
|
3.24' 2.42 |
3.88 2.90 |
4.841 3.64 |
6.48 4.84 3.52 |
|||||||
|
2.56 1.87 |
2. 72' 1.98 |
3.12 |
3.96' 2.89 |
|||||||
|
1.76 |
2.12 |
2.28 |
2.44 |
2.66 |
3.18 |
|||||
|
i H X K & |
1.24 |
1.32 |
1.40 0.94 |
1.50 1.00 |
1.60 |
1.72 1.16 |
L 1.86 |
2.04' |
2.24 |
2.48 [ 1.68 |
|
0.84 LJK52 |
0.88' 0.55 |
1.08 |
1.26 |
1.36 0.85 |
1.50 |
|||||
|
0.59 |
0.63 L 0.36 |
0.67 0.39 |
0.74 |
0.80 |
0.94' |
1.04 |
||||
|
0.30 0.22 |
0.32 0.23 |
0.34 0.24 |
0.42 |
0.46 L 0.33 |
0.49 |
0.54 |
( 0.60 |
|||
|
0.26 |
0.28 |
0.30 |
0.36 |
0.40 |
L 0.44 |
|||||
|
*/2 A H A X |
0.16 |
0.16 0.11 |
0.17 |
0.19 |
0.20 |
0.21 |
0.23 0.15 |
0.25 0.16 |
0.28 0.18 |
[ 0.32 0.21 |
|
0.12 |
0.13 0.08 |
0.13 0.08 |
0.14 0.09 0.05 |
|||||||
|
0.10 0.06 0.03 |
0.11 0.06 0.03 |
0.12 0.07 0.04 |
0.13 0.08 0.04 |
38
American Steel and Wire Company
Bending Stress for Different Sizes of Sheaves and Drums
For 6x19 Rope in Net Tons
|
Diam.of Rope in Inches |
Diameter of Sheave or Drum in Feet and Inches |
|||||||||
|
4'-0" |
3'-9" |
8'-G" |
3'-3' |
3'-0" |
2'-9" |
2'-6" |
2'-3" |
2'-0" |
IMP |
|
|
2K W 2X 2 1% |
31.84 |
33.96 |
25.60 |
[ 19.96 |
21.76 |
23.96 |
||||
|
22.40 14.96 |
23.881 15.96 |
|||||||||
|
17.12 |
18.44 |
|||||||||
|
1% IX Itt IX Itf |
12.00 9.44 |
12.80 |
13.72 L 10.76 |
14.76 11.60 8.96 |
16.00 12.56 9.68 |
17.46 |
19.20 15.08 |
16.72 12.96 |
14.56 10.88 7.92 |
12.48 9.12 |
|
10.02 7.76 |
13.70 10.58 7.92 |
|||||||||
|
7.28 5.44 |
8.32 |
11.64 8.72 6.36 |
||||||||
|
5.80 |
6.24] 4.56 j |
6.72 |
7.28 L 5.32 |
9.68 7.04 |
||||||
|
3.96 |
4.24 |
4.88^ |
5.78 |
|||||||
|
1 H X H ft |
2.80 |
3.00 |
3.20 2.16 |
[ 3.44 |
3.72 |
4.08 2.72 |
L 4.48 |
4.96 |
5.60 3.76 |
[ .6.40 |
|
1.88 1.18 |
2.00 1.26 |
2.32 |
2.52 |
3.00 1.88 |
3.861 |
4.32 [ 2.68 |
||||
|
1.34 |
1.48 0.84 |
1.60] 0.91 L 0.66 |
1.70 |
2.08 |
2.36 |
|||||
|
0.68 0.48 |
0.72 0.52 |
0.78" 0.56 |
0.98" 0.72 |
1.08 |
1.201 0.88 |
1.36 |
L 1.56 |
|||
|
0.60 |
0.801 |
0.96 1 |
1.12 |
|||||||
|
l/2 & H A X |
0.34 0.24 |
0.38 0.26 |
0.40 |
0.42 |
0.46 0.30 |
0.50 0.32 |
0.56 |
0:62 0.42 |
^0.68 |
0.80 |
|
0.27 0.17 |
0.28^ 0.18 |
0.36] 0.24 |
"0.47 0.30 |
0.54 0.33 |
||||||
|
0.15 0.09 0.05 |
0.16" 0.10 0.05 |
0.20 |
0.22 0.13 |
0.26 0.15 |
||||||
|
0.10 0.05 |
0.11 0.06 |
0.12] 0.06 |
0.14] |
0.17 |
0.19 L o.io |
|||||
|
0.07 |
0.07" |
0.08 |
0.09 |
For 6x19 Rope in Net Tons
|
Diam.of Rope in Inches |
Dia.meter of Sheave or Drum in Feet and Inches |
|||||||||
|
l'-6" |
l'-3" |
l'-0" |
0'-9' |
|||||||
|
2# 2^ 2X 2 1M |
||||||||||
|
Ifc 1# 1/8 IX ij* |
10.64 |
|||||||||
|
1 # X X A |
7.44 |
8.96 6.00 |
7.52 L 4.72 |
|||||||
|
5.04 3.20 |
||||||||||
|
3.76 2.16 |
||||||||||
|
1.82 1.32 |
2.72 1.82 |
|||||||||
|
1.60 |
||||||||||
|
% A H A X |
0.93^ 0.63 |
1.12 |
1.36 L 0.94 |
|||||||
|
0.72 0,48 |
||||||||||
|
0.40 0,23 0.12 |
0.60 0.34 |
|||||||||
|
0.28 0.14 |
||||||||||
|
0.17 |
American Wire Rope
39
Bending Stress for Different Sizes of Sheaves and Drums
For 6 x 37 Rope in Net Tons
|
Diam.of Rope in Inches |
Diameter of Sheave or Drum in Feet and Inches |
|||||||||
|
U'-O" |
18'-0' |
12'-0" |
ll'-O- |
lO'-O" |
9'-0" |
8MT |
7'-6' |
7' -or |
6'-6' |
|
|
2X 2^ 2X 2 1* |
11.11 |
11.97 8.99 |
12.96 |
14.15 10.63 |
15.56 |
17.40 12.99 |
19.45 |
20.75 L15.60 |
22.22 16.70 |
23.94 17.98 13.10 |
|
8.351 6.09 |
9.74 7.10 |
11.69 8.52 |
14.61 10.65 |
|||||||
|
6.55 4.62 |
7.75 |
9.47 L 6.67 |
11.36 L 8.00 |
12.18 8.58 |
||||||
|
4.291 2.89 |
5.00 |
5.45 3.68 |
6.00 1 |
7.50 |
9.24 L 6.22 |
|||||
|
3.11 |
3.38] |
4.05 |
4.50 |
5.06 |
[ 5.40 |
5.78 |
||||
|
1# IK 1# IX |
2.29 ' 1.80 |
2.47 j |
2.68 2.10 |
2.92^ 2.29 1.77 |
3.21 |
3.57 1 2.80 |
4.01 |
4.28^ 3.36 |
4.58 |
4.94 3.96 |
|
1.98 L 1.49 |
2.52 1.94 1.46 |
3.15 2.43 |
3.60 2,78 |
|||||||
|
1.39 1.04 |
1.62 1.22 |
2.181 1.62 |
2.59^ L 1.95 |
2.98 2.24 |
||||||
|
1.12 |
1.33 1 |
1.83 |
2.08 |
|||||||
|
1/8 1 # X # T9* |
0.76" 0.54 |
0.82 |
0.88 |
0.97 |
1.06 |
1.18 |
1.33 0.94 |
1.42 1.00 |
1.52 |
1.64 1.16 |
|
0.58 |
0.631 L 0.42 |
L 0.68 |
0.75 0.51 |
0.831 |
1.04 L 0.72 |
|||||
|
0.38 0.23 |
0.39 0.25 |
0.46] 0.29 |
0.56 |
0.63 |
0.68 |
0.78 |
||||
|
0.261 0.15 |
0.31 |
0.35 0.20 |
0.39 |
0.42 |
^0.46 |
0.50 |
||||
|
0.14^ |
0.17 |
0.18 1 0.13 |
0.23 0.17 |
0.24 0.18 |
0.26 |
0.28 [ 0.20 |
||||
|
0.12 1 |
0.151 |
0.19 |
||||||||
|
K TV X |
For 6 x 37 Rope in Nei Tons
|
Diam.of Rope in Inches |
Diameter of Sheave or Drum in Feet and Inches |
|||||||||
|
6-0' |
5'-6" |
5'-0" |
4'-6' |
4'-0" |
3'-9" |
3'-6' |
3'-3" |
3'-0" |
2'-9" |
|
|
2X 21A 2X 2 !M |
25.92 |
28.30 |
31.12 |
34.80 25.98 |
38.90 |
41.50 |
33.40 |
35.96 [26.20 |
20.00 |
21.80 ^14. 72 |
|
19.48 14.20 |
21.26 |
23.38 17.04 |
29.22 21.30 |
31.20 22.72 L16.00 |
||||||
|
15.50 10.90 |
18.94 13.34 |
24.36 17.16 |
||||||||
|
10.00^ 6.76 |
12.00 |
15.00" |
18.48 [12.44 |
|||||||
|
7.36 |
8.10 |
L 9.00 |
10.12" |
L 10.80 |
11.56 |
13.52^ |
||||
|
IH iK 1# IX 1% |
5.36 4.20 |
5.84 |
6.42 5.04 |
7.14 5.60 L 4.36 |
8.02 |
8.56 6.72 5.18 |
9.16 |
9.88 L 7.92 |
L10.72 |
11.68 L 9.16 |
|
4.58 3.54 |
6.30 4.86 3.66 |
7.20 5.56 4.16 |
8.401 6.48 |
|||||||
|
3.24^ 2.44 |
3.89^ 2.92 |
5.96 4.48 |
7.08 L 5.32 |
|||||||
|
2.66 1.94 |
3.24 2.36 |
3.90 [ 2.84 |
4.88^ 3.54 |
|||||||
|
1.76 |
2.13 |
2.66 |
3.04 |
3.28 |
3.88 |
|||||
|
i ft X X T9* |
1.26 |
1.36 0.92 |
1.50 |
1.66 L 1.12 |
1.88 |
2.00" |
L 2.08 |
2.32 |
2.52 1.68 |
L 2.72 |
|
0.84" 0.52 |
1.01 |
1.26 |
1.36 |
1.44 |
1.56 |
1.84 L 1.16 |
||||
|
0.58 |
0.63 L 0.36 |
0.70 |
0.78 |
0.84 [ 0.48 |
0.92 |
1.00 |
1.04 |
|||
|
0.30 0.22 |
0.33 0.24 |
0.40 0.30 |
0.44 0.33 |
0.52 0.38 |
0.56 0.41 |
0.61 |
L 0.68 |
|||
|
0.27 |
0.361 |
0.44 |
L 0.48 |
|||||||
|
# TV X |
L 0.23 |
0.25 |
0.26 |
0.29 |
0.31 |
0.34 L 0.23 0.14 |
||||
|
0.21 0.13 |
40
American Steel and Wire Company
Bending Stress for Different Sizes of Sheaves and Drums
For 6x37 Rope in Net Tons
|
Diam. of Rope in Inches |
Diameter of Sheave or Drum in Feet and Inches |
|||||||||
|
2'-6" |
2'-3" |
2'-0" |
l'-9" |
l'-6" |
r-ar |
l'-0" |
0'-9" |
|||
|
W 2^ 2% 2 1# |
24.00 16.20 |
18.00 |
20.24 |
|||||||
|
1# 1# 1/8 IX 1# |
12.84' 10.08 |
14.28 |
16.04 12.60 |
18.32 14.40 |
L 12.96 |
11.68 8.52 |
||||
|
11.201 8.72 |
||||||||||
|
7.78 5.84 |
9.72" 7.32 |
11.12 8.32 |
||||||||
|
6.48] 4.72 |
9.76 L 7.08 |
|||||||||
|
4.26 |
5.32 |
6.06 |
||||||||
|
1 ft X # A |
3.00 |
3.32 ] 2.24 |
3.76 |
4.16 |
L 5.04 |
6.00 4 04 |
7.52 5.04 |
|||
|
2.02 ' 1.26 |
2.52 1.56 |
3.08 |
3.36 2.08 |
|||||||
|
1.40] 0.80 |
1.84 |
2.521 |
3.12 |
|||||||
|
0.73 ' 0.54 |
0.92 0.66 |
1.04 0.76 |
1 22 |
1.401 |
1.84 |
|||||
|
0.60] |
0.88 |
1.08 |
1.32 |
|||||||
|
y2 A H |
0.38 0.25 0.16 |
0.41 |
0.46 0.31 |
0.52 |
0.62 0.42 |
0.76 |
0.92 |
|||
|
0.28] 0.17 |
0.39 0 23 |
0.50 1 0.32 |
0.62 |
|||||||
|
0.19 |
0.26 |
0.38 |
||||||||
American Wire Rope
II
Bending Stress for Different Sizes of Sheaves and Drums
For 8x 19 Rope in Net Tons
|
Diam. of Rope in Inches |
Diameter of Sheave or Drum in Feet and Inches |
|||||||||
|
7'-0" |
6'-0" |
5'-0" |
4'-6' |
4'-0' |
8'-9" |
8'-6" |
8'-8" |
3'-0" |
||
|
1# 1# IX 1# 1 |
3.29 |
3.84 [ 2.96 |
4.61 |
5.12 3.94 |
5. 76 |
6.15 |
6.58 |
L 7.10 |
7.68 5.92 |
|
|
2.54 1 1.91 |
3.55 2.67 |
4.44 3.34 |
4.73 1 3.56 2.59 |
5.08 |
5.47 1 4.11 |
|||||
|
2.22 1.62 |
2.96 1 2.15 1.52 |
3.82 2.78 |
4.44 3.24 |
|||||||
|
1.39 0.98 |
1.94 L 1.37 |
2.43 1 1.71 |
2.99 1 2.12 |
|||||||
|
1.14 ' |
[ 1.83 |
1.96 |
2.28 |
|||||||
|
H % fl A ^ |
0.65 0.41 |
0.76 |
0.91 0.58 |
[ 1.01 1 |
1.14 |
1.21 |
1.30 0.82 |
1.40 1 0.89 |
1.52 |
|
|
0.48 0.28 |
0.64 1 0.36 |
0.72 |
0.77 1 |
0.96 0.56 |
||||||
|
0.24 0.17 |
0.33 0.24 |
0.42 0.30 |
0.45 1 0.32 |
0.48 |
0.51 1 |
|||||
|
0.20 0.14 |
0.27 1 0.19 |
0.34 0.24 |
0.37 1 0.26 |
0.40 |
||||||
|
0.12 |
0.17 |
0.21 |
0.23 1 |
0.28 |
||||||
|
A X A X |
0.13 1 |
0.14 |
0.15 |
0.16 |
0.17 1 0.11 |
0.19 |
||||
|
0.12 |
For 8x19 Rope in Net Tons
|
Diam. of Rope in Inches |
Diameter of Sheave or Drum in Feet and Inches |
|||||||||
|
2'-9" |
8>-6' |
2'-3" |
2'-0" l'-9" l'-G' |
l'-3" |
l'-0" |
0'-9" |
||||
|
1# 1H IX V/B 1 |
8.38 |
9.22 [ 7.10 |
7.88 5.92 |
8.88 6.68 4.86 |
7.64 5.56 3.92 |
6.48 4.56 |
7.76 5.38 |
. |
||
|
6.45 4.85 |
||||||||||
|
5.34 3.88 |
||||||||||
|
3.53 2.49 |
4.30 [ 3.04 |
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|
2.74 |
3.42 |
|||||||||
|
% X X A g |
1.65 1.05 |
1.82 |
2.02 ' |
2.28 |
2.60 [ 1.64 |
3.04 |
3.64 2.32 |
4.56 2.88 1.68 |
2.24 1.60 |
|
|
1.16 [ 0.66 |
1.28 s 0.72 |
1.44 |
1.92 [ 1.12 |
|||||||
|
0.'60 0.44 |
0.84 0.16 |
[ 0.96 |
1.32 L 0.97 |
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|
0.48 [ 0.34 |
0.54 ' 0.38 |
0.68 0.48 |
L 0.80 |
1.20 L 0.86 |
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|
0.31 |
0.43 _ |
0.56 |
L 0.68 |
1.12 |
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|
& H A X |
0.20 |
0.23 0.14 |
0.26 0.16 |
0.28 |
0.32 0.21 |
[ 0.38 |
0.44 0.29 |
0.56 |
L 0.76 |
|
|
0.13 |
0.18 |
0.24 L 0.14 |
0.36 ' L 0.21 |
L 0.48 |
||||||
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0,12 |
0.14 0.09 |
0.28 0.20 |
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0,15 |
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42
American Steel and Wire Company
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American Wire Rope
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American Steel and Wire Company
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American Wire Rope 47
Section 3
Stresses Due to Fluctuation of Load in Starting and Stopping
The amount of stress upon a rope, the velocity of which changes fre- quently, is a factor dependent entirely upon the rapidity with which the change of velocity is made. A problem will make this perfectly clear. Let us consider a rope that is to lift a load vertically, starting from rest and to reach a certain speed within a given time.
Let t = the time of acceleration.
W = the weight to be lifted (mine cage, ore or similar proposition).
w = the weight of the rope per foot in pounds.
Er= the modulus of elasticity of the rope.
a = the acceleration or retardation of the load in feet per second.
S = the space in which the acceleration or retardation is made.
V = the velocity of the load in feet per second.
K — the kinetic energy of the load.
k = the kinetic energy of the moving rope.
Kt= the total kinetic energy.
1 = the length of rope hanging vertically.
g = the force of gravity.
Kt= K + k.
Kt= C (W + wl).
When C equals a constant by which the load is increased due to kinetic energy, C being a factor representing the increase of the total load.
Therefore, Kt = - —- - = (W + wl)
but V2 = 2 a S substituting we have C (W + wl) = — (W + wl) or a = — ^
o _
a 2 ts — 2g C. If t is equal to 1, a = \ 2 g C or a = 8.02j/C~~
In order to facilitate estimating the stresses, the following table has been calculated using the above formulae. In the first column are values of C rang- ing from 0 to 5.00, while in the second column are the corresponding acceler- ations (a) in feet per second, squared. The third column shows the corresponding velocities (v) in feet per second, and these values will also represent the distance in feet (S) the load would travel during one second. The fourth column shows the total stress factor, and the fifth the safety factor corresponding to the acceleration (a) upon the basis of a factor of safety of 10 with a quiet load.
48
American Steel and Wire Company
Stresses of Acceleration and Retardation
|
c |
a Feet per Second2 |
s Feet per Second |
C + 1 Total Stress Factor |
Safety Factor 10 for Quiet Load |
|
0. |
0. |
0. |
1.00 |
10.00 |
|
0.10 |
2.54 |
1.27 |
1.10 |
9.09 |
|
0.20 |
3.59 |
1.79 |
1.20 |
8.34 |
|
0.25 |
4.01 |
2.01 |
1.25 |
8.00 |
|
0.30 |
4.39 |
2.20 |
1.30 |
7.70 |
|
0.40 |
5.07 |
2 54 |
1.40 |
7.15 |
|
0.50 |
5.67 |
2.84 |
1.50 |
6.67 |
|
0.60 |
6.21 |
3.11 |
1.60 |
6.25 |
|
0.70 |
6.71 |
3.36 |
1.70 |
5.88 |
|
0.75 |
6.94 |
3.47 |
1.75 |
5.72 |
|
0.80 |
7.17 |
3.58 |
1.80 |
5.66 |
|
0.90 |
7.61 |
3.81 |
1.90 |
5.27 |
|
1.00 |
8.02 |
4.01 |
2.00 |
5.00 |
|
1.25 |
8.97 |
4.48 |
2.25 |
4.44 |
|
1.50 |
9.82 |
4.91 |
2.50 |
4.00 |
|
1.75 |
10.61 |
5.31 |
2.75 |
3.64 |
|
2.00 |
11.34 |
5.67 |
3.00 |
3.33 |
|
2.50 |
12.68 |
6.34 |
3.50 |
2.86 |
|
3.00 |
13.89 |
6.94 |
4.00 |
2.50 |
|
3.50 |
15.00 |
7.50 |
4.50 |
2.2$; |
|
4.00 |
16.04 |
8.02 |
5.00 |
2.00 |
|
4.50 |
17.01 |
8.50 |
5.50 |
1.82 |
|
5.00 |
17.93 |
8.96 |
6.00 |
1.67 |
•^ For example : With the value of C equal to 1, which corresponds to a change of kinetic energy equal to the load during the first second, the load could receive an acceleration of 8.02 feet per second2 or would have moved a distance of 4.01 feet, doubling the stress on the rope over that of the corre- sponding dead load : in other words, if the factor of safety were 10 with a quiet load, it would be 5 with the load accelerated 8.02 feet in the first second. It will thus be seen that it is very necessary that the acceleration at the start be gradual, in order to be sure that the stress is not unduly increased, because it may readily be seen that if the acceleration is sufficiently high, the rope would be in danger of being snapped off. This is particularly true of shorter lengths of rope.
While it is not impossible to break a long mining rope by a sudden starting of the engine, it is not as likely to occur in a long rope as it is in a shorter mining rope, owing to another factor which enters into the problem. This factor is the extension or permanent elasticity of a wire rope or the amount of stretch for different applications of load. For instance, with the value of C equal to 1, the following table shows the amount of extension which partly compensates for the stress on a rope at starting.
|
Length Rope Feet |
Extension Crucible Steel Feet |
Extension Plow Steel Feet |
Length Rope Feet |
Extension Crucible Steel Feet |
Extension Plow Steel Feet |
|
500 1000 1500 2000 2500 |
0.833 1.667 2.500 3.333 4.167 |
1.000 2.000 3.000 4.000 5.000 |
3000 3500 4000 4500 |
5.000 5.833 6.667 7.500 |
6.000 7.000 8.000 9.000 |
American Wire Rope
I'. I
This extension varies directly as the length of the rope. It will be noted from this table that taking a rope, say 2,500 feet long, if it were to be stressed to a value of C equal to 1 corresponding to an acceleration of 8.02 feet per second, the value of C would really not be as great as 1, owing to the fact that the stretch in the rope of 4.16 feet would be almost exactly equal to the space traversed in the first second or the value of C would be only .50. If, however, the value of C were increased, the factor of safety of course would be cut down correspondingly.
Section 4
Inclined Planes Many wire rope applications require that a wire rope operate on a slope or incline where the stress on the rope is a variable quantity due to the angle of the plane. The stress on a wire rope so employed is of course a function of the angle of inclination, the value of which can be accurately determined. A diagram and development of formula for making this calculation is given below.
Let 6 = the angle of inclination.
X = be = the height of the plane measured vertically.
Y = ac = the length of the incline measured horizontally.
Z = ab = the length of the incline measured along the slope.
P! = the pull on the wire rope due to load neglecting friction.
P2= the pull on the wire rope due to its own weight on the incline.
F = the friction factor which is a function of W.
W — weight resting on the incline.
P = the pull on the wire rope, friction and weight of rope included.
P
=P
Pa. WX
= sn e =
where W, X and Z are known.
50 American Steel and Wire Company
The friction F of the cars on the incline operates normally to the line ab and is therefore a function of cos d. The maximum friction is for a value cos 0=1 or on a dead level, and the minimum for cos 0 = 0 or 90° vertical. It is the starting friction which is the greater and if we take a value of 2% or -^ for this quantity we have
(1) _ Wcosfl
sin 0
50
Therefore P= Pt + F + P2= W sin e +W c°se +PZ= w (si
oO oO /
Take the weight of the rope into account
Let w = weight per foot of the rope 1 = length of rope on the incline.
(2) Therefore P2 = wl (si
\
sin 0
50 ;
(3) P = Px + F + Pg = (W + wl) (sin e +
LetC = (sme+C-°^} V 50 )
(4) Then P = (W + wl) C
For short inclines an approximate value of P may be obtained by neglect- ing the weight of the rope or
(5) P = C W
The values of C = (sin e H — — — jhave been plotted in a curve from which
50 /
it will be easy to pick the constant by which the load is to be multiplied to get the pull on the rope.
For a good many places the length of J;he incline makes it imperative that the weight of the rope be considered, and it is better to allow for this by using formula (3) or (4).
For obtaining the number of degrees on an incline we advise the use of a degree rule which is similar to a carpenter's two-foot rule containing a spirit level and a degree graduation. In case a rule of this kind is not at hand, the degree of inclination may be determined by measuring the vertical elevation in 100 feet of distance along the incline, and from curve on page 51 the degree can be found at once.
American Wire Rope
51
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American Steel and Wire Company
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QV01
American Wire Rope
Having found the degree of inclination, the curve on page 52 will give
the load factor or C = (sin d -\ — -jfrom which by formula (4) page 50, the
stress on the rope P is readily calculated.
EXAMPLE : A load of 50 tons is to be pulled up an incline of 20 feet per 100 feet of slope. The total length of the slope is 2000 feet. Required the size of rope necessary to handle the load if Plow Steel Rope 6 x 19 is to be used, and factor of safety of 0.
1. Get the approximate diameter of the rope by using formula (5) page 50.
For 20-foot rise per 100 feet of slope the degree of inclination = Il*4> (See page 51), and the load factor C = 0.22. (See page 52.)
Hence the approximate value of P = 0.22 x 50 = 11 tons.
This means a rope with a strength in excess of 66 tons.
A 1^-inch rope has a strength of 58 tons, and a 13/6-inch rope a strength of 72 tons. Let us take the 13/8-inch rope which weighs 3 pounds per foot. P = C (W + wl) C = 0.22 W = 100,000 pounds w = 3 pounds f = 2000 feet P = 0.22 (100,000 + 6000) = 23,320 pounds = 11.06 tons.
This shows that the 13/6-inch rope is the right rope to be used. In this case the weight of the rope added about 6 per cent, to the load.
Section 5
Stresses in Spans The subject of this chapter is one on which a book might easily be written if we were to include all the data
and statistical information available, but it would be difficult for the general reader to pick from such a mass of information the parts that would apply to the particular case under consideration.
There are times, hovfever, when a rope user wants to know quickly whether he can accomplish certain results with a cable suspended horizontally in the air between two towers or supports and it is for such purposes that the information contained in these pages is given.
The stress or tension on a cable suspended between two points is entirely different from that of any other type of rope application and is usually much greater than the suspended load. It is very necessary to recognize this fact because a rope sometimes breaks if the user has not made proper calculations of the stresses.
It is usually required that a cable span shall have as small a sag or center deflection as possible, which is of course the condition of maximum tension on a cable span.
54
American Steel and Wire Company
To show what some of the stresses present in a cable span are, it is necessary to only mention that all of the following factors must be considered carefully in important calculations :
1 . Weight or load to be supported by cable span
2. Position of load and whether position is stationary or movable
3. Weight of supporting cable
4. Stress due to fluctuations in temperature
5. Ice load
6. Wind load
7. Modulus of elasticity of cable used in span
8. Are both points of span support on a level?
9. Height of towers above any given datum line if points of
support are o?i different levels
10. Length of spa?i
11. Amount of deflection or dip in center of span
12. Length of cable hanging between supports
Other minor factors may need to be considered. In the case of large installations it is well to have the advice of the manufacturer so that all the various points may be given careful consideration.
The formula for calculating the stress in the case of a span with level supports is as follows :
Let L = the total span in feet = AB D = the deflection in feet = EF W = the dead load at point F w = weight per foot of the cable S = tension in the cable at F X = AE, the position of load W with reference to point A.
American Wire Rope 55
For the deflection due to weight of rope alone we have
-^pr
81)
the center of the span
This formula (1) is applicable to all cases of uniformly distributed load such as a wire rope or large guy strand used for supporting a lead telephone or power cable, or a bare copper high tension feeder cable, at frequent intervals. The value of w must be taken however as the total weight per foot of both suspended and supported cables.
The stress due to the weight alone is
S 2 = — — at the center of the span
(3) wL2 + 2WL L (wL+ 2W) Sl •* ~8D~ ~8D~
From the formula (3) we can get the stress on any cable due to load and weight of cable.
In order to facilitate these calculations we have devised curves for calcu- lating the strain, which are found on the following pages. In using these curves it should be borne in mind that they represent the distributed load. If the load is in the center it is necessary to multiply it by 2.
e. g. 1000 pounds in the center of a 100 span is = 2000 pounds distributed load or 20 pounds per foot
The curves are calculated on one pound per foot distributed load, so it is necessary to multiply the stress obtained from the curves by the distributed load per foot.
EXAMPLE : What stress is produced in a 1-inch rope weighing 1.6 pounds per foot on a 500-foot span with a deflection of 20 feet and a distributed load of 1000 pounds ? From the curve, page 56.
A 500-foot span and 20-foot deflection gives a stress of 1562.5 pounds.
Distributed load per foot = 1.6 + = 3.6 pounds
500
1562.5 X 3.6 pounds = 5625. pounds tension
The maximum stress on a cable span is at the supporting points A and B when the load is suspended in the center.
Tension at A or B = tension in center + the tension due to weight of rope wL and load W times the deflection I).
(4) T = S + D (wL + W)
The length of cable hanging between supports can be determined from the single curve for various ratios of sag to span, shown on page 56.
American Steel and Wire Company
NVds oiovs ouva
§ 3
American Wire Rope
133J Nl NOI1D31J3Q U31N3D
58 American Steel and Wire Company
Section 6
Stress Limitations of Machinery In connection with the use of wire rope
a very important factor, namely, the
power of the machinery, should be carefully considered. It is a well known fact that on many machines the pull which the engine drums are capable of exerting is very close to the strength of the rope, which is put on. This is considered bad practice because it permits overstraining of the rope and very often results in breaking it which may entail considerable damage. Users as well as designers of machinery should always ascertain the pull on a wire rope when full power is on, and if this approaches the strength of the rope, provision should be made in case of a steam engine or boiler to reduce the steam pressure or throttle the steam, and in the case of an electric motor to provide an automatic cut-out capable of regulating the maximum pull. Some unsuccessful applications of wire rope have had their trouble traced to this cause which may exist on a small or large piece of apparatus. A wire rope has a certain definite ultimate strength when new, but this should never be approached if good results are to be obtained.
Section 7
Multiple Sheave Blocks In a direct single line hoist, as shown by Fig. 1,
with a sheave of good diameter, the stress upon
the rope equals the load hoisted. By using a triple block with a double block, as in Fig. o, the five parts of the rope carry the load so that the stress upon each part is only one-fifth of the load. In brief, to ascertain the stress on the hoisting rope, divide the maximum load by the number of ropes, or by the number of parts of the same rope, carrying the hoisting hook and load, and add the bending stress to get the total stress on the rope. For bending stress, see Section 2, page 31.
American Wire Rope
59
60 « American Steel and Wire Company
Section 8
Wire Rope for Guys Many devices employing wire rope must be held in place by guy lines or ropes and since the action of
these ropes is different from that of ropes under a straight pull, it is necessary to calculate the stresses in them very carefully. In order to do this a table has been devised which shows the relation between the number of guys upon a derrick or similar piece of machinery and the equivalent effective number of guys acting for any position of the load. This latter quantity is known as the guy factor.
Reference to curve on page 03 shows the maximum and minimum values which the guy factor represents. If it is desired to find the number of guys working on a derrick, for example, all we have to do is to refer either to the table or to the curve and we will get directly the quantities involved. For example, on a derrick with 11 guys, the minimum value of the guy factor is 3.494 or, in other words, for any position of the load the derrick guys have a strength equal to 3.494 times the strength of one guy. Maximum values have been given but these should not be used in calculations. They have been given simply to show that there is a variable effective number of guys acting for different positions of the load.
Reference to the diagram, page 63, and the table page 61, will show conclu- clusively that it is best always to use an odd number of guys in guying a piece of apparatus of any size. This is because the maximum and minimum values of the guy factor are very close together for an odd number of guys, whereas with an even number of guys there is a much lower minimum value. For example, a derrick employing 6 guys has a guy factor of 1.732. The addition of one guy or increasing the guys by ^ will increase the value of the guy factor to 2.248, an increase of 30 per cent. In the interest of economy it is always advisable, therefore, to use a large number of guys. It is further very essential that the guys be spaced evenly so that the angle between each pair of guys is the same as that between every other pair. See page 98.
Another point that should be taken into consideration on guys is the angle that they make with the horizontal. It is apparent that when a guy pulls on the mast of a derrick that it will not give its full strength unless it pulls absolutely in a horizontal line. Whenever it pulls at an angle, the pull will be somewhat less than the total strength of the guy. Reference to curve on page 62 will show the value of the guy pull for various angles of the guy rope with the horizontal. The smaller the angle (9 of the guy of the horizontal the more effective the guy, but for practical purposes this angle may come up to about 26 degrees and still have at least 90 per cent of the strength of the guy. In figuring the strength of the guys, it is first necessary to get the guy factor by reference to curve on page 63 or the table on page 61, then refer to curve on page 62 and get the per cent of the guy acting and multiply this
American Wire Rope
(11
decimal by the guy factor. The result obtained is the amount of pull in a horizontal line or perpendicular to the mast of a derrick, which pull will act to support a load. This pull must be multiplied by a factor of safety of not less than 4 and preferably 5 for all loads to be lifted.
Values of Guy Factors and. Positions of Maximum and Minimum Values for Guy Ropes Equally Spaced
|
No. Guys |
Min. Values Guy Factor |
Corresponding Line of Action of Force |
Max. Values Guy Factor |
Corresponding Line of Action of Force |
|
3 |
0.866 |
30° from 1 iruy |
1 000 |
Opposite 1 guy or half way between 2 guys |
|
4 5 |
1.000 1.538 |
Opposite 1 guy 18° from 1 guy |
1414 1 618 |
Half way between 2 guys Opposite 1 guy or half way between 2 guys |
|
6 |
1.732 |
30° from 1 guy .... |
2.000 |
Opposite 1 guy |
|
7 |
2.193 |
12° 51 ' from 1 guy . . . |
2.248 |
Opposite 1 guy or half way between 2 guys |
|
8 |
2.414 |
Opposite 1 guy .... |
2.611 |
Half way between 2 guys |
|
9 |
2.835 |
10° from 1 guy .... |
2.879 |
Opposite 1 guy or half way between 2 guys" |
|
10 |
3.078 |
18° from 1 guy .... |
3.236 |
Opposite 1 guy |
|
11 |
3.494 |
8° 11' from 1 guy |
3.514 |
Opposite 1 guy or half way between 2 guys |
|
12 |
3.732 |
Opposite 1 guy .... |
3.864 |
Half way between 2 guys |
|
13 |
4.120 |
6° 55' from 1 guy |
4.150 |
Opposite 1 guy or half way between 2 guys |
|
14 |
4.381 |
12° 51' from 1 guy . . |
4.494 |
Opposite 1 guy |
|
15 |
4.757 |
6° from 1 guy .... |
4.783 |
Opposite 1 guy or half way between 2 guys |
|
16 |
5.027 |
Opposite 1 guy .... |
5.126 |
Half way between two guys |
|
17 |
5.399 |
5° 18' from 1 guy |
5.422 |
Opposite 1 guy or half way between 2 guys |
|
18 |
5.671 |
10° from 1 guy .... |
5.758 |
Opposite 1 guy |
|
19 |
6.046 |
4° 44' from 1 guy . . |
6.054 |
Opposite 1 guy or half way between 2 guys |
|
20 |
6.314 |
Opposite 1 guy .... |
6.392 |
Half way between 2 guys |
62
Americaii Steel and Wire Company
|
GUY ROPES CURVE SHOWING RELATION BETWEEN ANGLE OF GUY ROPE WITH THE HORIZONTAL AND THE PER CENT OF THE GUY ACTING AT ANY GIVEN ANGLE. |
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American Wire Rope
63
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64 American Steel and Wire Company
Section 9
Factors of Safety In the previous sections many of the principal forms of stresses that are commonly present in wire rope applica- tions have been considered. Not all of them are present in any one case, but the factor of safety must always be considered. The proper selection of this factor is of vital importance, for on it depends to a great extent the success- ful operation of ,any mechanism employing wire rope.
While it is not possible to give exact figures which should be employed for the many uses of wire rope, still certain general principles can be evolved which will indicate very approximately the figures that should be used. It is the practice of some users of wire rope to use a large factor of safety and figure on only dead load, whereas the load is probably a live one and the rope is bent around fairly small sheaves. In a case of this kind a large factor of safety may allow for the increased stress, but at best it is an unsatisfactory way to treat the subject. It is much better to determine what the stresses are and then apply a simple factor of safety.
In the eight preceding sections we have considered the principal stresses to which a wire rope is subjected, and if these stresses are calculated wherever any of them occur and the result added to the already known load upon the rope, it will facilitate the use of an ordinary factor of safety. The figures given in the catalogue are for a factor of safety of approximately 5, neglecting the bending stress. This amounts to a net factor of safety of between 4 and 4^ when this is considered with the sheaves given in the table. We would not recommend a factor of safety much lower than these figures for any class of work, and for a good many places the factor of safety ought to be larger. For example : It is the practice on elevators to have the wire rope calculated on a factor of safety of from 5 to 10, and similar practice is found in many mining propositions where the rope is not very long, the reason for which has already been explained in Section 3 of this chapter. Where ropes are very long, as sometimes occurs in mining practice, the weight of the rope itself is sufficiently great to deduct considerably from the strength of the rope. When this is the case the factor of safety is sometimes cut down as low as 4^ , because it is not possible to get quite as large a factor of safety as might otherwise be desired. For slow speed the factor of safety may be somewhat less than for high speed.
For example : A derrick frequently works on what would be considered in other places a very low factor of safety, and the reason for it is that the load is steady and the speed slow enough so that there is no added strain on the rope other than that due to the load and the bending stress over the sheaves. In fast operating machinery, however, such as ore and coal handling clam shell buckets, the factors of safety employed are usually greater, and some run up as high as ten. It is generally conceded the greater the factor
American Wire Rope 65
of safety the longer the rope will last and the safer it is. Particular pains must be taken to avoid having too large a factor of safety.
For example : The factor of safety such as 25 is altogether too large and the result is somewhat like using a 1-inch rope where a f^-inch would do. In other words, a rope could not give its best results under such light loading as a factor of safety of 25 would indicate. Every device using wire rope has of course to be considered on its own merits, as regards the selection of a factor of safety. On ballast unloader rope, such as is used for plowing material from flat cars by means of a plow and a wire cable, it frequently happens that the strain on the rope may run up to nearly one-half its breaking strength. This is because it is not possible to use a large drum and a larger rope and handle it economically, but such heavy loading in a case like this, where there is no risk to life, should not be taken as a precedent for heavy loading under other conditions where it is possible to use a sufficiently heavy rope. Derrick guy ropes are frequently strained severely when an exception- ally heavy stone is lifted, but it is never safe to strain them on the heaviest possible lift to over one-third of the breaking strength of the guys. It is probably true that the greater number of applications requiring the quick handling of loads employ a factor of safety ranging from 5 to 10.
B — Size and Quality of Rope to Meet the Stresses
Having carefully considered the various stresses found in a wire rope and calculated them in accordance with the nine preceding sections, the question naturally arises — what size of rope should be used for a given con- dition? This cannot be answered off hand, but there are factors entering into the problem which can be briefly generalized. In the first place, Section 2 must be carefully considered on all problems, and an unusually high bending stress in a rope is an indication that its life will be rather short. If on the other hand the bending stress is not excessive, the service obtained should be fairly good. Rope users should refer to the tables of bending stresses *for the construction which they propose to use and see what this amounts to before definitely deciding upon any construction In case of doubt as to which construction should be used our engineers are always ready to consider the problem and give the customer the benefit of our experience.
In general, it might be noted that in a rope of a given strength we could use on hoisting rope say 1-inch crucible steel or a J^ inch plow steel and get almost exactly the same factor of safety. In a case where the sheaves must of necessity be small, the ^6 -inch plow steel probably would be preferable to the 1-inch crucible steel, referring of course to the same construction.
The figures given in the lists for proper working loads should be used for rough calculation only, because the factor of safety should be carefully
66 American Steel and Wire Company
considered as outlined in Section 8 of this chapter and the proper factor of safety selected for the work at hand.
The relative strengths of the various materials in a wire rope are given in Chapter II, dealing with materials. This is also shown by the various strengths given in Chapter IX.
Sections 1, 2, 3 and 8 will enter into consideration of practically every common wire rope problem. The remaining Sections 4, 5, 6 and 7 enter into the consideration of special rope problems. See page 30.
American Wire Rope
Chapter VI
Suggestions to Rope Users
The success or failure of a wire rope installation often hinges upon practical points which are sometimes overlooked. Such being the case there have been compiled a number of suggestions gathered from our long experience which are offered to the trade not as a final word but as an indication of what should be avoided and what may be beneficial to wire rope service.
How to Gauge Wire Rope The diameter of a wire rope is the diameter
of the circle which will just enclose all the
strands. Care should be taken in gauging a wire rope to take the greatest and not the smallest diametrical dimension, as shown above.
Sheaves and Drums Most wire rope applications use sheaves over which the rope runs and drums upon which it winds.
These are indispensable units and the use of as large drums and sheaves as practicable is strongly recommended. Particularly attention is called to the section descriptive of bending stresses of rope found in the chapter on "Wire Rope Stresses," page ol. The effect of too small sheaves and drums will readily be seen by making a calculation in accordance with the information given therein. Drums should be lagged if possible, and wherever feasible the use of a grooved drum on hoisting machinery is recommended as better than
68 American Steel and Wire Company
a flat drum without grooves. It is important to have the grooves on drums spaced so that there is ample clearance between the successive windings. For example : A drum for a ^ inch rope should be arranged so that the grooves are not nearer than, say ^ of an inch on centers. This will prevent undue crowding or rubbing of one part or wrap of a rope against another. The grooves of sheaves and drums should be made smooth in order not to cut the wires of the rope which winds upon it. They also should be made of a slightly larger radius than the rope which is to run on them so that the rope will not wedge nor pinch.
Overwinding It is also important wherever possible to have the drum large enough or wide enough so that the wire rope may wind upon it in one layer.
The term overwinding has been applied to cases where wire rope has to wind two or more layers deep on a drum. This is a very bad condition and one that should be carefully avoided, because the wire rope will mash and jam more or less and will not last nearly as long. It may be a little more expensive to provide a larger drum and may necessitate a change in the gearing of the machinery, but for the best working conditions and lowest cost of operation overwinding must be avoided.
Alignment of Sheaves and Drums The best possible alignment of sheaves
and drums should be obtained, other- wise there will be undue wear on the side of the sheaves and drums as well as on the rope. In general the lead sheaves over which the rope runs from the drum should be lined up with the center of the drum, or if the drum is not entirely filled it should be in line with the center of that portion of drum on which the rope is wound.
Leads It is necessary to have the proper amount of space between the lead sheave and the drum in order to avoid too sharp an angle. We recom- mend an angle not exceeding 1° 30' between the line from the center of sheave to center of drum and the line from the center of sheave to the outer side of drum.
Renewal of Sheaves The upkeep of a piece of machinery is essential in order to secure the best wire rope service. If sheaves
become badly scored or worn, a new rope will not work properly and many careful users of wire rope insist on changing the sheaves or turning out the grooves before a new rope is put on. This insures best conditions for rope service. For mine hoisting in particular the best practice is to make the large sheaves and drums with liners which can be taken out and renewed when they wear out or whenever a new rope is installed.
American Wire Rope
Speed of Wire Rope A high velocity on a wire rope means that the rope will not last as long as if only a medium velocity were
employed. Of course a high velocity means that more work is accomplished in a given time, but it is better to have the load increased and the rope slightly larger with the speed correspondingly slower to get the best results as far as tonnage handled.
Reversed Bending By this term we refer to that sort of bending in which a wire rope is first bent around one sheave in one
direction and at some other section the same rope is passed around another sheave with a bend diametrically opposite. This is an exceedingly severe condition of rope service and its use should be avoided wherever possible. There is no known way in which a wire rope may be worn out more rapidly by bending than by the use of the reversed bend. We have practically demonstrated that this is one of the severest conditions that wire rope has to meet. In many places by a little study or a slight change in design this feature can be avoided. It is of sufficient importance that many users of rope cha-nge their machinery over to get around it on account of the vastly increased service which they obtain from a rope where this condition is absent. Reverse bending cannot be too strongly condemned. There is a very limited number of cases where this reversed bending cannot be avoided, and at such times the rope has to be sacrificed, but knowing the bad effects resulting from such reversed bending, it is desired to sound a note of warning that should be heeded by all.
Handling of Wire Rope It is not probable that any one would intentionally
mishandle a piece of wire rope in installing it, but
we feel that a word of caution should be given. In the first place a wire rope does not handle like a manila rope, in that structurally it differs. It must not be coiled or uncoiled like a hemp rope. If it is received in a coil it should be unrolled on the ground like a hoop and straightened out before attempting to pass it around the sheaves on machinery. If it is received upon a reel, the reel should be mounted upon jacks or a shaft so that it will turn and the rope be properly unwound.
Sudden Stresses It is very essential to avoid sudden stresses or jerks on a wire rope because this increases the load to a great extent, as will be noted by reference to Chapter V, Section 3, page 47. A simple experiment will demonstrate the effect of this. A piece of twine fairly strong may be easily snapped by a quick pull.
Galvanized Rope This is not used for general hoisting or general pur- poses because the zinc wears off rapidly from running over sheaves and drums. Galvanized ropes are about 10 per cent less in
70 American Steel and Wire Company
— 7?
strength than ungalvanized ropes. The strengths forv galvanized ropes not shown in this catalogue can be furnished upon application.
Protectiftn of Wire Rope A wire rope that runs out of doors should be
protected as far as possible from the weather by
the application of some suitable lubricant. We manufacture a lubricant which is an especially heavy compound for coating wire rope. It will adhere as tenaciously as any compound that we know of and has been successfully used for this purpose. All ropes, whether for inside or outside work, should be given some lubrication to keep them pliable. If this lubrication is omitted, internal as well as external rust may set in, stiffening the rope and causing it to give poor service. See page 199.
Working Loads These have been carefully considered in Chapter V, Section 9, but a good rule to follow is that these should not exceed one-fifth of the ultimate breaking stress of the rope. On a guy rope this is sometimes exceeded, but it never should be in mines or elevators where human life is at stake.
Wire Rope Transmission There are not a great many applications requir- ing an endless wire rope for transmitting power.
Such applications, however, require pulleys lined with wood, leather or rubber in order to ensure the most successful operation. See page 234.
Rope Exposed to Heat A few conditions exist where rope is exposed to
intense heat and at such places a soft iron wire
center is usually substituted, and sometimes asbestos. The latter, however, rapidly disintegrates under constant bending, and we therefore do not recom- mend its use. For either of these special centers add 10 per cent to the list price of rope with hemp center.
American Wire Rope
71
Chapter VII
How to Order Wire Rope
Use the exact terms given in catalogue describing the rope required, stating length, size, diameter (or circumference), quality, number of strands, number of wires in the strand, and whether hemp center or wire center is wanted, also whether bright or galvanized is desired, e. g., 750 feet long, 1^ inches in diameter, plow steel hoisting rope, six strands, nineteen wires, hemp center, one piece.
If rope is to be equipped with thimbles, sockets, hooks, links, loops or other fittings, state the length from the pull of thimble, socket, hook, link, loop, etc., to end of the rope. Where fittings are to be put on each end, be sure and state the length from pull to pull of fittings.
If in doubt as to the material to be used, the conditions under which the rope operates should be given or a sample of rope that is satisfactory sub- mitted so that the proper quality and construction may be furnished.
If possible, submit a rough sketch with the order, or inquiry showing the size and relative position of the sheaves, together with the figures of maximum load in pounds. This greatly facilitates a complete understandir ~ of the require- ments which the rope must fill. See page 72.
When ordering rope for elevators, state whether hoisting, counterweight, or hand or valve or safety rope is wanted, also whether right or left lay is desired. The ropes used for these purposes all differ and are not inter- changeable.
For convenience in installing elevator hoisting or counterweight ropes when used in pairs or two-part lines, we will, at no extra expense, wind the rope upon a reel with the length of rope doubled in the middle so that the loop will come off the reel first or last as desired.
Further information is contained in Chapter VIII on practical applications of wire rope, pages 72-118.
American Steel and Wire Company
Chapter VIII
Practical Wire Rope Applications
The vast number of devices employing wire rope as a flexible medium for utilizing mechanical or electric power in the handling of various commercial problems, would require a large work if each were to be but briefly described. The leading principles involved can, however, be shown by a few typical illustrations selected from the many that are available. The following seven- teen divisions have been chosen for illustration :
Page
1. Aeroplanes ......... 73
2. Cableways and tramways .,«... 74
3. Cable roads ......... 77
4. Clam shell buckets 79
5. Cranes .......... 81
6. Derricks 83
7. Elevators — hydraulic, electric and power driven . . 85
8. Excavating machinery, including dredges, steam shovels, etc. 92
9. Ferries 96
10. Guying for derricks, ships, etc. ..... 97
11. Loading and unloading machinery . . . . .102
12. Lumbering, including skidding and loading . . . 104
13. Mining rope arrangements ...... 107
14. Oil well drilling 114
15. Suspension bridges . . . . . „ . .116
16. Stump pulling ........ 117
17. Towing devices . . . . . - . . . 118
In order to more clearly show the rope action, the working parts of the machinery involved alone have been depicted in most cases, all details that would obstruct the clearness of the diagrams having been omitted.
Wire rope for any of the purposes detailed in this chapter, as well as many others, can oe supplied, but in case customers have machinery of the types shown herein, it will facilitate a clear understanding if reference is made in correspondence to the type of the machinery that is being used, provided it is illustrated herein. Machinery shown represents commercial machinery of leading machine builders in the United States.
American Wire Rope
7:5
Division 1
Aeroplanes One of the latest comers into the field of wire rope users is the aeroplane, and for its use special kinds have been devised known as aeroplane stay strand and flexible rudder steering cord (page 183).
.| " i| || 'i. t. .! !, i! II .1 II V !l i II n FT
74
American Steel and Wire Company
Division 2
Cableways and Tramways Cableways consist of one or more large stationary
track cables stretched between suitable towers
with auxiliary smaller ropes for moving the mechanism. The principal use of cableways is for conveying large loads for a limited distance between the two main towers, also for excavating, dam building, canal work, logging, deep pit quarrying, and the conveying of any bulk material where natural obstructions interfere with any other method of operation. It is preferable to use for the
Si
S3
o o
American Wire Rope
75
main cables the locked wire track cable shown on pages 24 and 101, especially if the cableway is for constant operation, as the efficiency will be greater than the round wire cable described on page 190. The first cost of the locked wire type is of course greater than that of the round wire cable, but the increased life of the former makes it cheaper in the long run.
The two types of cable ways shown below are among the latest types and are facsimiles of the thirteen now being used at the Panama Canal, building the locks at Gatun. Each uses a two and one-quarter-inch locked wire track cable for the main cable.
76
American Steel and
Company
As usually constructed, cableways may be used to handle a single load at any point between the towers and discharge at any other point between them, either into cars or to a spoil bank.
Aerial Tramways are recognized in contradistinction to cableways in the fact that, as ordinarily constructed, they are designed to move a number of lighter loads in a continuous circuit over comparatively long distances. The materials are carried in receptacles (buckets usually) suspended from carriages on stationary track cables of the Locked Coil construction (see page 190) supported at varying elevations above the ground.
The loaded carriers travel along a line of track cable in one direction, and the empty carriers in returning along a similar parallel track cable, these cables being of sizes corresponding to the weights they have to support. Motion is imparted to the carriers by a comparatively light endless rope commonly known as the traction rope, by means of large sheaves at either end, one for driving, and the other, which is usually mounted on a slide actuated by a counterweight, for maintaining the requisite tension in this rope. The application of tension, however, may be at either terminal station as desired. The carriers are despatched at definite intervals, determined by the individual loads, the amount of material to be transported in a given time, and the speed. For further particulars parties are referred to our separate pub- lication entitled "Aerial Tramways," which fully describes and illustrates the various equipments of this kind that we manufacture.
~SS 2W5 «fe *5 355-
PROFILE OF BUEICHERT AERIAU TRAMWAY
American \Vire Rope
77
Division 3
Cable Roads Before the introduction of electric power for street railways, cable roads were very largely used. They are still used for very steep inclines, and also on industrial narrow gage roads.
The illustrations which follow show a large broad gage industrial cable road, also two narrow gage industrial roads used on docks for handling coal and iron ore. Also an illustration of an incline railway running up a mountain.
CABLE ROAD
CAP. GKIP.S
c
•i 1 1-
H 1
COAL DOCK HAULA6E ROAD AND BFUDGC
78
Americaii Steel and Wire Company
— I 1 1 1 1 1 l—
COAL DOCK HAVLACE «OAO OOVBIC. U<»OP
L)
o
ORE DOCK HAULAGE ROAD FOR BROAD GUAGE CARS
American Wire Rope
79
Division 4
Clam Shell Buckets These consist of two scoops pivoted together and operated by two sets of ropes known respectively as
the holding rope and the opening or closing rope. The former is attached to the top of the bucket by means of a thimble or socket spliced into the end of the rope, while the opening or closing rope passes down into the bucket and around several sheaves variously arranged to give a heavy force to close the two jaws of the bucket. The various types of bucket differ in the methods of working the opening and holding ropes. Various sizes are in use at different points varying from one ton up to twenty tons capacity. As a general propo- sition the bucket usually weighs nearly as much as the load it carries, the weight being necessary to give sufficient strength as well as digging power.
80
American Steel and Wire Company
American Wire Rope
SI
Division 5
*
Cranes For handling large objects in buildings, warehouses, shops, etc., electric overhead traveling cranes are largely used. Their operation is simple, consisting of a drum electrically driven and a wire rope tackle block of sufficient number of parts and suitable size of rope to handle the required loads with proper safety factor. For steel mills and hot metal cranes, foundries, as well as for crane service in general, the 6 x 37 rope illustrated on pages 141 and 142 will be found particularly useful.
ELECTRIC TRAVfcUIINC CRANE.
82
American Steel and Wire Company
OH®
LOCOMOTIVE CRANE
American Wire Rope
83
Division 6
American Patent Non-spinning Hoisting Ropes on Back-haul Quarry Derricks
The back-haul derrick derives its name from the fact that the great lifting purchase is obtained by means of multiple back-haul blocks, or tackle, moving up and down the back of the mast. The pulling line from the tackle blocks runs through the derrick step to the hoisting engine. For the large single hoisting line, American Non-spinning Rope is now universally employed, having a socket and hook, or socket and shackle, at one end, the other end being attached by four or five Crosby clips to the lower tackle block on the back of the
LARCt SINGLE LINC BACK HAUL DERRICK
mast. This lower block is made heavy so as to overhaul the slack line when the engine drum is released. From 25 to 50 tons may be lifted with a single line, and by doubling the line through the shaft at the hoisting hook, from 50 to 100 ton loads are handled with a medium size hoisting engine. The boom line runs out at the top of the mast direct to the engine. The bull wheel at the base of the mast is connected with the engine slewing drum by two wire lines which enable the engineer to swing the boom with its load in either direction.
The special feature of this derrick is the single hoisting line which possesses the following advantages : No heavy sheave block is required at the hoisting hook. The socket and hook, or socket and shackle, on the end of the single
84
American Steel and Wire Company
line, are easily carried about the quarry in order to reach and drag in blocks beyond the radius of the boom. The boom may be raised or lowered or swung in either direction while hoisting or lowering the load.
In lifting heavy loads with a single line, hoisting rope of the ordinary construction permits the load to revolve. This spinning of the free load sus- pended by a single line could only be prevented by attaching to the granite blocks a tag line held by one or two men while the blocks are being hoisted and swung into place. By the adoption of American Non- spinning Rope on these single line derricks, heavy loads may be raised into the desired position without the use of a tag line, because the free load does not rotate.
MEDIUM SIZE OUARRr DEJWCK
CRANC DERRICK
American Wire Rope 85
Division 7
Elevators An elevator is a lifting mechanism consisting of a cage or car propelled by suitable power, operated to raise or lower passengers or freight.
The proper operation of these elevators necessitates a medium by means of which the power for raising or lowering the car may be applied. In the early days of elevators, chain was sometimes used, but it was found to be unreliable and so wire rope has taken its place. The reason is of course the liability of breakage due to defective welds in the various links of the chain, which liability increases with the length of chain used, and also the crystaliza- tion of the links of the chain from constant strain and bending. A wire rope composed of a large number of wires, each tested individually and then manu- factured, possesses the reliability so necessary for transmitting and controlling mechanism of an elevator.
In order to place the matter clearly before the reader we have divided elevators into three classes as follows:
1. Hydraulic
a . Direct plunger type.
b. Side plunger type.
c. Horizontal plunger type.
2. Electrically driven
a. Electric geared elevator,
b. Electric traction elevator,
3. Worm geared elevators
a. Electric.
b. Belt driven.
American Steel and Wire Company
a. Hydraulic Elevators
of the direct plunger type employ counterweight ropes, valve or hand rope (sometimes called shipper
rope), and safety stop ropes.
b. Side Plunger Elevators depend upon the plunger for counterweight and
usually have a regulating rope to control the
speed of the cage in case of accident or excessive speed. The other ropes are the main hoisting ropes and the valve or hand rope.
American Wire Rope
87
SIDE PLUNGER
c. Horizontal Plunger Elevators require counterweight ropes, main hoist- ing ropes, hand or valve ropes and regulating ropes.
88
American Steel and Wire Company
HORIZONTAL PLUN6ER ELEVATOR
Valve ropes are largely operated by means of a shifter lever situated in the elevator car, although if the speed is not too great they may be operated by hand.
Direct hydraulic elevators have been successfully used on buildings up to twenty-one stories.
American Wire Rope
89
2. Electrically Driven Elevators a. The electrically geared elevators have
various methods of operation, but the two
principal ones are to place the elevator drums either in the basement or the attic of a building. With the drum in the attic two sets of ropes are used, the main hoisting ropes and counterweight ropes. Both are attached to the same drum and as one set of ropes wind on the other set wind off.
With drums located in the basement there are three sets of ropes known as main hoisting ropes, car counterweight ropes and drum counterweight ropes.
ELECTRIC
ELECTRIC OR BELT DRIVEN ELEVATOR
American Steel and Wire Company
3. Worm Geared Elevators These are used principally in factories where
power is already available and are belted and
worm geared to insure safety and moderate speed. These elevators require main hoisting ropes, car counterweight ropes and hand rope or shifter rope.
WORM GEARED ELEVATOR
American Wire Rope
b. Electric Traction Elevators
use the same set of ropes for both hoisting and counterweight purposes, there being
two drums around which each rope passes from the car to the counterweight.
This type of elevator has been used on some very tall buildings.
ELECTRIC TRACTION ELEVATOR
American Steel and Wire Company
Division 8
Excavating Machinery, including Steam Shovels, Dipper and Suction Dredges
For dry land excavation, for railroad, canal or irrigation work, steam shovels are largely used. A good many of the most modern shovels use rope exclusively for digging in place of chain which was formerly considered indis- pensable for shovel work. Almost all shovels, however, use wire rope for swinging cables. Some of the principal types are shown diagrammatically below.
STEAW SHOVEL.
American Wire Rope
For excavating under water dredging is almost universally resorted to, and either the dipper or the suction type of dredge used. The dipper dredge resembles the steam shovel except that it is a component part of a boat, whereas the steam shovel operates from a railroad car platform. Various sizes of dippers are used, depending upon the size of the dredge boat, three-quarter yard up to twelve yards being the commercial range. The smaller sizes of dredges are mostly used for drainage, ditching and dock construction, while the larger sizes are employed in digging deep channels in lakes and harbors. Ropes used are of three kinds, main hoisting cable, swinging cable and spud cables.
LARGE OIPPCR DREDGE
MEDIUM DIPPER DREDGE
American Steel and Wire Company
h
SPVD RCPCS
AUCTION
Large dredges use two or three parts of medium sized rope or one part of a very large rope frequently made with a wire center to get additional strength. Small dredges for canal work employ bank spuds, but large dredges employ steel-capped timber spuds.
Suction dredges consist of a rotary cutter and hydraulic suction pump through which the excavated material passes. The rotary cutter is mounted
American Wire Rope
95
on a ladder which can be lowered or raised as required by the ladder hoist ropes. One pair of swinging cables attached to anchors and around the ladder sheaves and winding on separate drums swing the dredge back and forth while the spuds keep the cutter from backing off. Suction dredges are employed for digging wide channels and the excavated material is carried on pontoons through a discharge pipe to suitable dumping ground.
Bucket Ladder Dredge with Conveyor
96
American Steel and Wire Company
Division 9
Wire Rope Ferries These are operated by means of an overhead cable and a ferry traveler running upon the same. A tackle block
is arranged forward and aft, and the boat is carried across the stream by means of the current, the boat being reversed or carried at an angle to the current, which acts as the propelling medium in a manner similar to that shown in the sketch below.
l\
\\
WIRE
American Wire Rope
97
Division 1O
Guying for Derricks, Ships Rigging, Stacks, Etc.
Galvanized ropes are employed almost exclusively for this class of work on account of their durability. The stresses on guy ropes at various angles are fully described in Chapter V, Section 8, pages 60 to 63. Wherever possible guy ropes should be equally spaced all around the derrick, smokestack or mast which it is desired to guy because in most cases the strain on the guys due to the load will come at some time with equal effect on all the guy ropes. In quarries the derrick guy ropes are sometimes passed around trees and fastened with Crosby clips, or an eye bolt is made fast to a part of the rock in the quarry and the guy rope made fast by means of Crosby clips and thimble or a shackle.
Where derricks have to be moved occasionally, or guys moved for any reason, the guy ropes may be made up in sections with thimbles spliced in each end of each piece. These are generally 50 or 100-foot lengths, so that they can be lengthened or shortened at will. Such a fastening is illustrated below.
When it is necessary to guy very securely, double guys are used, e. g., instead of twelve separate guys, six pairs may be used with fairly good results.
In order to take up slack in guy ropes, galvanized iron turnbuckles such as shown on pages 220 and 221 are used. Separate turnbuckles are required on each of the guys requiring to be tightened.
American Steel and Wire Company
3 GUYS
•6-
GUYS
GUYS
6 GUYS
7 GUYS
6 GUYS
GUYS
10 GUYS
II GUYS
4- PAIR GUYS 5 PAIR GU/S 6 PAIR GUYS
American Wire Rope
99
Plan of Smokestack Gnys of C. S. Battleanip Connecticut n>-» ol ial v»ui*ed iron, 0 •traaiU, 7 wire* each, 2 1>2 inohra ciroumlereuce. 18.OOO i
Guys on Battleship Connecticut
The stacks of the Connecticut are guyed with galvanized iron guy rope composed of six strands of seven wires each about a hemp center, having a strength of nine tons. On the top of the stacks and at the midway anchorages they are fastened to the stacks by means of heavy galvanized shackles, and upon the deck, turret and flying bridge anchorages, they are fastened by means of turnbuckles. The guys running between the stacks are similarly anchored, turnbuckles being inserted on the bowsides of the second and third stacks. The guy ropes attached to the flying bridge are made of phosphor bronze, because the use of steel or iron rope would affect the magnetic instruments in the chart room just below them. The turnbuckles attaching them to the flying bridge are also made of phosphor bronze.
The tables, page 101, show how largely wire rope has displaced manila rope for yacht rigging. The advantages possessed by an American galvanized plow steel wire rope over manila rope may be given briefly as follows :
It does not shrink nor stretch as does all manila rope.
Has seven times the strength of the same size of manila rope.
Is one-third the diameter of manila rope of the same strength.
Is 50 per cent lighter than manila rope of the same strength.
Being made of heavily galvanized wires, it does not rust nor rot, but is good for many years of hard service.
100
American Steel and Wire Company
Guys on Sailing Yacht
Specifications of the Wire Rope and Manila Rope
Employed in the Equipment of the
Yacht "Taormina"
Designed and Built by Geo. Lawley & Son, Boston American Wire Rope Used
A. Mainsail D.
B. Foresail E.
C. Fore-staysail F.
The Sails
Jib
Jib topsail
Small jib topsail
G. Foregaff-topsail
H. Main gaff-topsail
I. Main topmast-staysail
Sail and Rigging Plan oi Yacht
American Wire Rope J, , , ;V', \ ' ',/> ^; j'v 10J,J'
The Crucible Wire Rope
Galvanized Plow Steel Hoisting Rope, six strands, nineteen wires each, one hemp center.
Flexible for running through blocks.
|
Circumference in Inches |
Diameter in Inches |
Circumference in Inches |
Diameter in Inches |
||
|
W 1 |
1M |
K |
W 18 |
IX |
TV |
|
W 2 |
IK |
K |
W 20 |
IX |
TV |
|
W 8 |
iK |
W 21 |
IX |
||
|
W 11 |
\y% |
H |
W 22 |
i* |
|
|
W 12 |
IX |
yV |
W 28 |
||
|
W 16 |
IX |
W 32 |
IK |
K |
|
|
W 17 |
IX |
TV |
Galvanized Plow Steel Standing Rope, six strands, seven wires each, one hemp center.
For standing shrouds or straight hauls only. Not for running through blocks.
|
Circumference in Inches |
Diameter in Inches |
Circumference in Inches |
Diameter in Inches |
||
|
W 3 |
2 |
H |
W 19 |
IX |
. |
|
W 4 |
IK |
K |
W 23 |
3 |
|
|
W 5 |
2 |
W24 |
2X |
||
|
W 6 |
IX |
TV |
W 25 |
IX |
TV |
|
W 7 |
IX |
TV |
W 26 |
K |
|
|
W 9 |
IX |
_7 |
W27 |
2 2 |
^ |
|
W 10 |
2 |
^ |
W 29 |
3 |
1 |
|
W13 |
IK |
K |
W30 |
IX |
|
|
W 14 |
K |
W 31 |
IX |
V |
|
|
W 15 |
IX |
The Manila Rope Rigging
Four strands, long fibre.
|
Circumference |
Diameter |
Circumference |
Diameter |
||
|
in Inches |
in Inches |
in Inches |
in Inches |
||
|
M 1 |
2K |
if |
M 6 |
2X |
X |
|
M 2 |
IX |
TV |
M 7 |
||
|
M 3 |
IX |
TV |
M 8 |
IX |
TV |
|
M 4 M 5 |
IX IX |
£ |
M 9 M10 |
2X |
r |
The use of manila rope is confined to the sheets and lower purchases on halyards and backstays. The topmast backstay W 9, is of wire with a manila purchase near the deck for greater convenience in handling and fastening to the deck cleats. The upper parts of halyards are of wire, but the lengths leading on to the deck are of manila.
Ainerican Steel and Wire Company
Division 11
Loading and Unloading Machinery For the handling of bulk materials such
as iron ore, coal, etc., from vessels to
cars, there have been designed in recent years very efficient hoists employing some kind of clam shell bucket. For unloading iron ore from vessels we have ore conveyors or ore bridges, and for unloading coal, the coal tower. The various ore handling machines are usually named from their makers, and Brown hoists, Hewlett machines, fast hoists, etc., are familiar names to many rope users. The diagrams shown below illustrate some of the types in common use.
CUE UNLOADE* P.I6
ORE UNLOADER RlG
American Wire Rope
103
CPE UNLOADED
3A'_LK5r VNUOAPER AND TRAIN.
104
American Steel and Wire Company
Division 12
Lumbering, including The great lumbering industry depends for its suc-
Skidding and Loading Cessful operation to a marked degree on getting the
logs to the mill with the least possible expense. To
facilitate this, there have been devised skidding machines of different kinds, loaders and pull boats.
Where the ground is swampy, overhead cableway skidders are largely used, but where the ground is firm a portable skidding machine with one or two booms is usually employed for medium sized timber. For very large timber, however, it is customary to mount a large engine, boiler and geared drum on a heavy log platform and pull the logs in by main force. The type of machinery is thus adapted to the character of the work, and it is also true that the kinds of wire rope employed for these several uses have been designed to meet as far as possible the character of the machinery and the kind of work to be performed. In no other industrial work is wire rope worked under such con- stantly heavy loads, and it is not surprising that under such conditions that sometimes a strand breaks or the rope parts. Logs frequently foul with roots, stumps and other logs, and much skill is required of operators of skidding machines to get out the logs promptly without unduly overstraining the rope. Where timber is located along a navigable stream, pull boats are frequently used which pull logs for several miles out of the woods.
OVERHEAD LOG SKIDOtR
American Wire Rope
105
•4 LINE SKIODER WITH DECKING LINES
COWBINtD SKIDOER AMD LOADER
106
American Steel and Wire Company
LOG LOADER
o
SKIDDING Rape
GROUND -SKID0ER
American Wire Rope
107
Division 13
Mining Rope Arrangements For vertical shaft work it is customary to use
almost universally the 6x19 construction rope
of one of the grades shown on pages 129-131 of this handbook. The cages are usually arranged in pairs so that as one is lowered the other is raised, this being known as the balanced hoist system. Two types of hoisting drums are in common use, the flat drum and the conical drum, the latter being designed to give a slower starting speed when the cage is lifted from the bottom of the mine.
D
BALANCED HOIST FLAT DRUMS
D
BALANCED HOIST CONICAL DRUMS
108 American Steel and Wire Company
The simplest arrangement is for the ropes to pass directly from the drum to two head sheaves carried on a wooden or steel tower, each sheave lined with the center of that part of the drum on which the rope has to wind. It is customary with either the flat or conical drum to attach one rope to the under side of the drum and the other rope to the top of the drum, leaving several turns on the drum when the cage is resting on the bottom of the mine shaft. The names " underwind " and " overwind " are applied to these two ropes.
Conical drums are used more frequently on shorter mine ropes, but unless the smaller end has nearly as large a diameter as would be used for a flat drum, the rope service may not be much better than with a flat drum. It is a debatable point as to which type of drum is the better.
We recommend wherever possible that installations of mine hoist ropes be made with as few bends as possible in a similar manner to the two preceding diagrams. In case a shaft has to be changed or if the engine room cannot be located, so as to carry the rope in the manner indicated, a turn sheave may be used with suitable lead and intermediate supporting sheaves to carry the rope.
American Wire Rope
109
BALANCED WHITING HOIST
HIM
6X19 ROPE
Mine haulage systems are very widely different one from another, so much so that it may almost be said that there are hardly any two alike. At the same time there are in common use three leading systems known respectively as
1. Endless Haulage Rope System.
2. Tail Rope System.
J. Gravity Inclined Plane.
110
American Steel and Wire Company
1. The endless system consists of a wire rope usually Gx7 construction, spliced endless with small cars gripped on to the rope at regular intervals either singly or in groups of two or three. Two kinds of drum driving arrangements are usually employed known as the elliptical and the figure 8 style respectively. The elliptical arrangement is preferable to the figure 8 as the rope in the latter case is subjected to reverse bending on the drums. Suitable slip rings should always be used on drums to equalize the tension of the different winds of rope, and a tension carriage with counterweight is also necessary. Position of engine and driving drums is usually dependent upon the location of pit mouth. Slow speed of about 3 to 4 miles per hour is the average of this system.
ENDLESS ROPE HAULAGE SYSTEM
ENDLESS ROPE HAULAGE SY-STEM
American Wire Rope
111
6X7 ffOPC
LNDLESS ROPE HAULAGE
ENDLE.S5 ROPE HAULAGE SYSTEM
112
American Steel and Wire Company
2. Tail rope systems consist of two ropes known respectively as head line and tail line, the latter usually being about double the length of the former. Each rope is carried upon a separate drum and it differs from the endless system in that its operation is intermittent and the cycle of operations is for the head line to pull out a trip of about fifty loaded cars at a speed of about ten miles per hour. The time taken for the trip is dependent upon the length of the head line. The tail line is always attached to the rear car of the trip and as soon as the loaded cars have been run to the tipple by gravity, an empty trip of cars is pulled back into the mine by the tail line while the head line is at the same time attached to the front end of the train. The train of loaded cars or empty cars, as the case may be, is thus always under perfect control whether coming from the mine or returning to it.
TAIL ROPE HAULAGE SYSTEM
_LL
6 K7 F?OP£
TAIL ROPE HAULAGE SYSTEM
American Wire Rope
113
TAIL ROPE HAULAGE SYSTEM
TAIL ROPE HAULAGE SYSTEM
114
American Steel and Wire Company
Division 14
Oil Well Drilling The oil wells of the United States use many thousands of feet of wire rope in the drilling of wells. The first thing
that is done to drill an oil well is to erect a square tapering tower, or derrick as it is called, some 90 to 100 feet high. At the top of the derrick are located the sheaves for the drilling line and sand line, also the tackle block for the tubing or casing line.
Oil Well Drilling Rig With Carnegie Steel Derrick
American Wire Rope 115
The first operation of drilling is known as spudding and consists in starting the well and drilling a short distance. The early portion of the work is fre- quently done with manila rope and the well drilled to a depth of 600 to 800 feet. Wire rope is, however, being successfully used for the whole length and gradually displacing manila, especially where drillers are using the most advanced methods. Below a depth of 600 or 800 feet wire rope is almost invariably used.
Wells are usually started with 10-inch or 12-inch casing which is carried down as far as possible, when the next size smaller is inserted and carried down a considerable distance farther. It frequently happens that a well has to be finished with 4-inch casing. For each different size of casings different sizes and weights of tools are used, depending upon the character of the soil through which the well is being dug. After drilling a short time the drilling line and tools are pulled out of the well and the well bailed out with the sand line which is attached to a tube with valve in the bottom known as a bailer that is lowered to the bottom of the well and back again as often as may be necessary to get out the mud and water. Another length of casing is then attached to the main casing after drilling about 20 feet and the casing lowered that far before drilling is resumed. The above method is usually followed where the soil conditions are such that the hole is liable to cave. If, however, the drilling is through rocky ground the casing is usually placed at the time the drilling of the well is completed.
The successful drilling of an oil well is not a matter of chance, but requires a high degree of skill, for the well driller must be able to tell by placing his hand on the drilling line just how his drills are working. Many difficulties may be encountered, such as the casing becoming crooked and the rope wearing it in two, or the tools may stick and the rope break in getting them out, requiring a fishing job to recover the tools. All these conditions must be met by the drilling line. Our drilling lines are especially constructed to meet these conditions. Either the 6 x 19 or the 6 x 7 extra strong crucible steel, left lay, may be used for this work, although the 6x 19 rope should prove the superior of the two constructions, on account of its greater flexibility. See pages 123 and 130 of this book.
Further particulars about oil wells will be found in a separate pamphlet which will be sent upon request to those who are interested in this line of wire rope activity.
116
American Steel and Wire Company
Division 15
Suspension Bridges While very large suspension bridges are not composed of twisted wire cables, still smaller highway bridges
and foot bridges may be so easily and cheaply made by using wire ropes as to be worthy of attention. The ropes usually used for this work are those shown on pages 175 and 181 of this book. Two suitable towers are necessary, one on either bank of the stream and the main ropes passed over the towers and carried back to suitable anchorages. Such a bridge is illustrated below.
If the vertical suspenders are short, rods may be used together with clamps, washers and nuts and the cross floor timbers attached to them. The figures necessary to calculate the size of the cables are the total weight to be supported by each cable per foot, due to weight of floor and suspender rods, and also the maximum live load on the bridge at any given time, and whether the live load is uniformly distributed or in the center of the span. The formulae and information in Chapter V, pages 53 and 57, may then be used to calculate the size of bridge cables.
American Wire Rope
117
Division 16
Stump Pulling To clear land of stumps or imbedded rocks, a stump pulling or grubbing machine is almost universally used. This grubbing machine consists of a compact horse-power windlass upon which a wire rope is wound, the outer end being fastened around the stump or rock to be removed. Only wire rope of great strength and toughness can withstand the severe strain and the bending stresses incident to this service.
GROSSING rvtACHIMe FOR 5TUIY1P PULLING
118
American Steel and Wire Company
Division 17
Towing Devices For all heavy sea and lake towing, tugs and towing steamers are equipped with automatic steam towing machines and galvanized steel wire hawsers. The hawser from the tow leads directly on to the towing machine drum, which is operated by steam. In a sea way, the tension of the hawser varies. Under a heavy strain the hawser is drawn from the drum, but as the drum rotates it opens the engine throttle until the steam pressure in the cylinders equalizes the pull on the hawser. When the tension is diminished, the steam causes the engines to haul in the hawser to its normal position, when the throttle is automatically closed. Thus a uniform tension is maintained on the hawser. The service requires an extra galvanized steel hawser of great flexibility and strength.
American Wire Rope
119
Catalogue Section
Chapter IX
List Prices of Wire Rope
Issued Jan. 1, 1913. Subject to Change Without Notice
No.
1 Transmission Rope .....
2 Hoisting Rope .......
3 Extra Flexible Rope .....
4 Special Flexible Rope .....
5 Flattened Strand Rope .....
6 Tiller Rope .......
7 Non-spinning Rope .....
8 Steel Clad Hoisting Rope ....
9 Galvanized Guy Rope .....
10 Galvanized Running Rope ....
11 Galvanized Hawsers and Mooring Lines
12 Galvanized Bridge Cables ....
13 Sash Cord ........
14 Galvanized High Strength Aeroplane Strand
15 Galvanized Flexible Aeroplane or Motor
Boat Cord .......
16 Galvanized Mast Arm .....
17 Stone Sawing Strand .....
18 Galvanized Strand ......
19 Track Strand, Round and Locked . .
20 Clothes Lines .......
21 Flat Rope ........
22 A. S. & W. Shield Filler .
12O-125 126-132 133-137 138-143 144-155 155
156-16O
162-171
175
177
178-18O 181 182 183
183 184 184
186-188 189-191 192-193 194-198 199
120
American Steel and Wire Company
Wire Rope Lists
Transmission, Haulage or Standing Rope
We present these lists in the order of their flexibility, from the least flex- ible to the most flexible.
This rope is composed of 6 strands of 7 wires each, all laid around a hemp core. Their detail application is explained briefly under each of the five following lists. The particular advantage of this type of con- struction consists in its coarse wires which resist abrasion and corrosion to the greatest possible extent. It is not a flexible rope, however, and when- ever used must have the largest possible sheaves and drums over which to operate.
This rope is made in five grades or strengths, as follows :
1. Iron
2. Crucible Cast Steel
3. Extra Strong Crucible Cast Steel
4. Plow Steel
5. Monitor or Improved Plow Steel and Tico Special
American Wire Rope
121
Iron Transmission, Haulage or Standing Rope
Standard Strengths, Adopted May 1, 1'JIO 6 Strands— 7 Wires to the Strand— 1 Hemp Core
|
List Price per Foot |
Diameter in Inches |
Circum- ference in Inches |
Approximate Weight per Foot in Pounds |
Approximate Strength in Tons of 2000 Pounds |
Proper Work- ing Load in Tons of 2000 Pounds |
Diameter of Drum or Sheave in Feet Advised |
|
$0.51 |
!£ |
4X |
3.55 |
32 |
6.4 |
16 |
|
.43 |
IK |
4X |
3 |
28 |
5.6 |
15 |
|
.36 |
IX |
4 |
2.45 |
23 |
4.6 |
13 |
|
.30 |
IK |
3/^ |
2 |
19 |
3.8 |
12 |
|
.24 |
i |
3 |
1.58 |
15 |
3 |
10.5 |
|
.18# |
K |
2X |
1.20 |
12 |
2.4 |
9 |
|
'.14 |
-^X |
.89 |
8.8 |
1.7 |
7.5 |
|
|
.12 .10 |
I |
2 8 |
.75 .62 |
7.3 6 |
1.5 1.2 |
7.25 7 |
|
.08X |
IX |
.50 |
4.8 |
.96 |
6 |
|
|
.06^ |
K |
1# |
.39 |
3.7 |
.74 |
5.5 |
|
.05^ |
yV |
IX |
.30 |
2.6 |
.52 |
4.5 |
|
.04^ |
H |
1/8 |
.22 |
2.2 |
.44 |
4 |
|
.03^ |
T6* |
1 |
.15 |
1.7 |
.34 |
3.5 |
|
A |
# |
.12^ |
1.2 |
.24 |
3 |
All ropes not herein listed and composed of more than 7 and less than 19 wires to the strand, with the exception of 6 x 8, take 19 wire list. Siemens- Martin steel rope, having 25 per cent greater strength than iron rope, at same prices as iron rope. Add 10 per cent to prices for wire center or galvanized rope.
Iron haulage rope is not extensively used at present, except in some of the smaller sizes. It is composed of very soft wires, which do not possess high tensile strength. Some of the sizes given above are never used, but figures are given for comparison with the stronger grades.
122
American Steel and Wire Company
Crucible Cast Steel Transmission, Haulage or Standing Rope
Standard Strengths, Adopted May 1, 1910 6 Strands- 7 Wires to the Strand— 1 Hemp Core
|
List Price per Foot |
Diameter in Inches |
Circum- ference in Inches |
Approximate Weight per Foot in Pounds |
Approximate Strength in Tons of 2000 Pounds |
Proper Work- ing Load in Tons of 2000 Pounds |
Diameter of Drum or Sheave in Feet Advised |
|
$0.60 |
IX |
4X |
3.55 |
63 |
12.6 |
11 |
|
.51 |
Itt |
4X |
3 |
53 |
10.6 |
10 |
|
.43 |
IX |
4 |
2.45 |
46 |
9.2 |
9 |
|
.36 |
in |
3^ |
2 |
37 |
7.4 |
8 |
|
.29 |
3 |
1.58 |
31 |
6.2 |
7 |
|
|
.22^ |
H |
2^ |
1.20 |
24 |
4.8 |
6 |
|
.17 |
If |
2X |
.89 |
18.6 |
3.7 |
5 |
|
.uy2 |
2>^ |
.75 |
15.4 |
3.1 |
4X |
|
|
.12 |
&£ |
2 |
.62 |
13 |
2.6 |
4^ |
|
.10 |
T9* |
1# |
.50 |
10 |
2 |
|
|
.08 |
1A |
1# |
.39 |
7.7 |
1.5 |
3^ |
|
.06^ |
7 T7? |
1^ |
.30 |
5.5 |
1.1 |
3 |
|
.05^ |
H |
w |
.22 |
4.6 |
.92 |
2# |
|
.04^ |
A |
1 |
.15 |
3.5 |
.70 |
2X |
|
.04 |
A |
# |
.12# |
2.5 |
.50 |
IX |
All ropes not listed herein and composed of more than 7 and less than 19 wires to the strand, with the exception of 6 x 8, take 19 wire list. Add 10 per cent to list prices for wire center or galvanized rope.
This rope covers a wide range of utility, being particularly adaptable for use in mine haulage work, which includes tail rope and endless haulage sys- tems, gravity hoists, as well as coal and ore dock haulage roads operating small grip cars. In sizes, ^, T7-g, }4, T\, ^, it rinds use as sand lines for oil wells, and in the larger sizes, fyfa, %, fa, 1, is sometimes used for oil well drilling. In general, rope from this list can be used where abrasion is severe and flexibility required a minimum quantity.
American Wire Rope
123
Extra Strong Crucible Cast Steel Transmission, Haulage or Standing Rope
Standard Strengths, Adopted May 1, 1910 6 Strands— 7 Wires to the Strand— 1 Hemp Core
|
List Price per Foot |
Diameter in Inches |
Circum- ference in Inches |
Approximate Weight per Foot in Pounds |
Approximate Strength in Tons of 2000 Pounds |
Proper Work- Diameter ing Load in of Drum or Tons of 2000 Sheave in Pounds Feet Advised |
|
|
$0.75 |
1# |
4X |
3.55 |
73 |
14.6 11 |
|
|
.64 |
1H |
4X |
3 |
63 |
12.6 |
10 |
|
.53 |
IX |
2.45 |
54 |
10.8 |
9 |
|
|
.44 |
i# |
3^ |
2 |
43 |
8.6 |
8 |
|
.35 |
3 |
1.58 |
35 |
7 |
7 |
|
|
.27 |
H |
2X |
1.20 |
28 |
5.6 |
6 |
|
.20 |
X |
2X |
.89 |
21 |
4.2 |
5 |
|
.17 |
H |
2^ |
.75 |
16.7 |
3.3 |
4X |
|
.14X |
H |
2 |
.62 |
14.5 |
2.9 |
4^ |
|
.12 |
& |
« |
.50 |
11 |
2.2 |
4 |
|
.09^ |
% |
IX |
.39 |
8.85 |
1.8 |
3^ |
|
.07^ |
T7* |
IX |
.30 |
6.25 |
1.25 |
3 |
|
.06 |
^8 |
1H |
.22 |
5.25 1.05 2% |
||
|
.05^ |
T5* |
.15 |
3.95 |
.79 |
2X |
|
|
.05 |
A |
H |
.13# |
2.95 |
.59 |
IX |
All ropes not listed herein and composed of more than 7 and less than 19 wires to the strand, with the exception of 6 x 8, take 19 wire list. Add 10 per cent to list prices for wire center or galvanized rope.
This being the next stronger rope of this construction, its use is prac- tically the same as that of the crucible steel, except that in many cases a smaller rope can be used and the same strength obtained. This rope also covers a wide range of utility, being particularly adaptable for use in mine haulage work, which includes tail rope and endless haulage systems, gravity hoists, as well as coal and ore dock haulage roads operating small grip cars. In sizes -3/6, T7^, *^, T9^, y%, it finds use as sand lines for oil wells, and in the larger sizes, f£, ^, ?/8, 1, is sometimes used for oil well drilling. In general, rope from this list can be used where abrasion is severe and flexibility required a minimum quantity.
r_>4
American Steel and Wire Company
Plow Steel Transmission, Haulage or Standing Rope
Standard Strengths, Adopted May 1, 1910 6 Strands— 7 Wires to the Strand— 1 Hemp Core
|
List Price per Foot |
Diameter in Inches |
Circum- ference in Inches |
Approximate Weight per Foot in Pounds |
Approximate Strength in Tons of 2000 Pounds |
Proper Work- ing Load in Tons of 20UO Pounds |
Diameter of Drum or Sheave in Feet Advised |
|
$0.90 |
1# |
4X |
3.55 |
82 |
16.4 |
11 |
|
.76 |
IX |
4X |
3 |
72 |
14.4 |
10 |
|
.62 |
IX |
4 |
2.45 |
60 |
12 |
9 |
|
.51 |
1# |
3X |
2 |
47 |
9.4 |
8 |
|
.41 |
1 |
3 |
1.58 |
38 |
7.6 |
7 |
|
.32 |
# |
2X |
1.20 |
31 |
6.2 |
6 |
|
.24^ |
X |
2X |
.89 |
23 |
4.6 |
5 |
|
.21 |
2^ |
.75 |
18 |
3.6 |
4X |
|
|
.17# |
^8 |
2 |
.62 |
16 |
3.2 |
4^ |
|
.14^ |
I9T |
IX |
.50 |
12 |
2.4 |
4 |
|
.11/2 |
K |
Itf |
.39 |
10 |
2 |
3^ |
|
.09 |
TV |
IX |
.30 |
7 |
1.4 |
3 |
|
.0614: |
^8 |
1# |
.22 |
5.9 |
1.2 |
2X |
|
.06 |
A |
.15 |
4.4 |
.88 |
2X |
|
|
.05^ |
A |
H |
.12^ |
3.4 |
.68 |
IX |
All ropes not listed herein and composed of more than 7 and less than 19 wires to the strand, with the exception of 6x8, take 19 wire list. Add 10 per cent to list prices for wire center or galvanized rope.
This is a very strong rope, and its wires are harder and capable of with- standing more external wear than the softer crucible steel. Its general scope of application is for mine haulage, including endless, tail rope systems and gravity hoists, as well as ore and coal dock haulage roads operating small grip cars. Where it is necessary to secure increased strength and the physical requirements render it impossible to alter the working conditions, a plow steel rope may be used to distinct advantage without increasing the diameter of the rope.
American Wire Rope
125
Monitor Plow Steel Transmission, Haulage or Standing Rope
Standard Strengths, Adopted May 1, 1910 6 Strands -7 Wires to the Strand— 1 Hemp Core
|
List Price per Foot |
Diameter in Inches |
Circum- ference in Inches |
Approximate Weight per Foot in Pounds |
Approximate Strength in Tons of 2000 Pounds |
Proper Work- ing Load in Tons of 2000 Pounds |
Diameter of Drum or Sheave in Feet Advised |
|
$1.05 |
1# |
4X |
3.55 |
90 |
18 |
11 |
|
.88 |
1# |
4X |
3 |
79 |
46 |
10 |
|
.72 |
IX |
4 |
2.45 |
67 |
13 |
9 |
|
.58 |
1# |
3K |
2 |
52 |
10 |
8 |
|
.48 |
1 |
3 |
1.58 |
42 |
8.4 |
7 |
|
.37 |
H |
2# |
1.20 |
33 |
6.6 |
6 |
|
.28^ |
X |
2X |
.89 |
25 |
5 |
5 |
|
.24^ .20^ |
if |
S* |
.75 .62 |
20 17# |
4 3.5 |
4X 4X |
|
.17 |
A |
W |
.50 |
13 |
2.6 |
4 |
|
.13^ |
% |
W |
.39 |
11 |
2.2 |
3/2 |
|
.11/2 |
TV |
IX |
.30 |
1% |
1.5 |
3 |
|
• 08X |
H |
IX |
.22 |
Q/2 |
1.3 |
2X |
All ropes not listed herein and composed of more than 7 and less than 19 wires to the strand, with the exception of 6 x 8, take 19 wire list. Add 10 per cent to list prices for wire center or galvanized rope.
This is the strongest rope of this construction, and although somewhat stiffer than the preceding qualities, may be used to advantage where conditions are suitable. For its strength it is the toughest rope that can be made, and in general a smaller diameter rope of this type should be used than any of the preceding qualities. When this is done it will give a good account of itself. Its uses are similar to those described under plow steel, extra strong and crucible steel. Sheaves for this rope should be somewhat larger than for the preceding qualities if possible, in order to get the very best results. Tico special rope, sold from same list.
126 American Steel and Wire Company
Standard Hoisting Rope
6 Strands— 19 Wires to the Strand— 1 Hemp Core
This term is applied to hoisting rope composed of 6 strands of 19 wires each, laid around a hemp core. It has a wide and varied list of applica- tions, some of the principal ones of which are detailed under their respective lists. It is composed of smaller wires than the 6x7 construction and is more readily passed around sheaves and drums of moderate size. Its wires being smaller, it will not stand as much abrasion as the coarser transmission rope.
This rope is made in six grades or strengths as follows :
1 . Iron
2. Mild Steel
3. Crucible Cast Steel
4. Extra Strong Crucible Cast Steel
5. Plow Steel
(>. Monitor or Improved Plow Steel and Tico Special
American Wire Rope
127
Standard Iron Hoisting Rope
Standard Strengths, Adopted May 1, 1910 6 Strands— 19 Wires to the Strand— 1 Hemp Core
|
List Price per Foot |
Diameter in Inches |
Circum- ference in Inches |
Approximate Weight |