US2445365A

US2445365A - Wire rope and method of manufacturing the same

Info

Publication number: US2445365A
Application number: US631606A
Authority: US
Inventors: Eugene J Reardon
Original assignee: American Steel and Wire Company of New Jersey
Current assignee: American Steel and Wire Company of New Jersey
Priority date: 1945-11-29
Filing date: 1945-11-29
Publication date: 1948-07-20
Anticipated expiration: 1965-07-20

Description

' WIRE ROPE AND METHOD OF MANUFACTURING THE SAME Filed Nov. 29, 1945 2 Shets-Sheet 1 bzvenfor: 5065M? J. 1650200,

July 20, 1948. E. J. REARDON 2,445,365

WIRE ROPE AND METHOD OF MANUFACTURING THE SAME Filed Nov. 29, 1945 2 Sheets-Sheet 2 lnvezdax' [UGE/Vf J. Emma/z ffa 4Q Patented July 20, 1948 UNITED STATES PATENT OFFICE WIRE ROPE AND METHOD OF MANUFAC- TUBING THE SAME Eugene J. Beardon, Mount Lebanon, Pa., assignor to The American Steel and Wire Company of New Jersey, a corporation or New Jersey Application November 29, 1945, Serial No. 631,606

their proper position and in the position that theywill assume when the rope is in use; that is, the strands of the rope should be formed or stretched before they are laid in position to form the rope so as to eliminate any distorting or stretching of the same after the rope is in use.

Heretofore, various methods have been suggested and used in order to obtain a rope in which the component parts are permanently laid in their proper position so as to prevent distortin and stretching thereof after the rope is in service but such methods did not attain the desired result due to certain variables that occur. These variables have resulted in an unbalanced condition within the rope and imperfections in the rope resulted after the rope was in use which was unsatisfactory. These imperfections included excessive stretch in the rope, spotty wear, and high and low strand wear. Also in the case of a wire rope laid up with a fibre core, the core may have been too small in diameter and too low in weight or too low in hardness or density. oftentimes the center or core strand would tend to bulge out between the outer strands or disintegration thereof would result, particularly if a fiber cen ter was used.

Wire rope is usually manufactured on a ropemaking or stranding machine which consists generally of a plurality of rotatable cradles with each adapted to hold a reel or spool of stranded wire. The cradles are arranged concentrically about the axis of the machine with the axes of the cradles arranged substantially parallel thereto. The cradles are adapted to be rotated around the axis of the machine and. at the same time, about their respective axes. In such machines there is usually provided a closing die through which the strands or the rope is pulled by a haul-oil mechanism. e I

In the use of such a machine, a core member or strand is fed up through the center thereof and through the closing die to the haul-of! mechanism. The stranded wire passes from the spools .12 Claims. (01.57-145 on the cradles and is wound or twisted around the core member upon rotation of the cradles around the axis of the machine in a well-known manner. It is the P rpo e of the closing die to force the outer wire strands inwardly into position around the core strand or member after the wire strands have been twisted and helically wound into position around the core or center member; that is to say, the outer wire strands are moved to posi- I tion around the core member by the compression of the closing die.

Such a method does not make a satisfactory wire rope and the imperfections heretofore mentioned result. Wire rope produced by such a method stretches when loaded after a short period of use. The primary reason that such stretch results is that the compression exerted on the strands by the closing die does not remove the stretch from the strands and, therefore, mechanical stretch in the wire strands is not removed therefrom at or before the time they are twisted or wound into position around the core member.

According to the present invention, it has been found that if suflicient tension is applied to each of the strands between the reels or spools holding the coils of stranded wire and the point of twist of the strands around the center or core member so that the strands are under tension at the point of twist, the strands are permanently set into position around the core and a rope having the characteristics of a prestretched rope is produced It is a further object of the invention to provide an improved method of manufacturing wire rope and the like which is simple and inexpensive in its use and, at the same time, emcient and effective.

It is a more specific object of this invention to provide an improved method of manufacturin wire rope and the like wherein a uniform tension is applied to all of the strands as they are helically wound around the core member to form the rope so that the pitch of the helices of each of the strands is uniform and substantially equal to the 3 pitch which the strands will assume when the rope is finished and in use.

It is a further object of the present invention to provide a wire rope having a fiber center of increased weight.

It is a still further object of the present invention to provide a wire rope having a fiber center of increased hardness.

Various other objects and advantages of this invention will become more apparent during the course of the following specification and will be particularly pointed out in the appended claims.

In the accompanying drawings there is shown, for the purpose of illustration, an embodiment which my invention may assume in practice.

Figure 1 is a schematic ordiagrammatic view showing the arrangement of apparatus for practicing my improved method of manufacturing wire rope and the like;

Figure 2 is a detailed view showing the wire strands passing through the annular laying or guide member;

Figure 3 is a plan view of a section of a rope made by my improved method;

Figure 4 is an enlarged curve showing the helices of the rope shown in Figure 3;

Figure 5 is a vertical section through a vertical rope-laying machine showing tensioning means incorporated therewith for practicing the method of my invention; and 4 Figure 6 is an elevational view of a modified form of tensioning means of my invention.

Referring more particularly to the drawings, there is shown in Figure 1, a schematic view of apparatus for practicing the teachings of the present invention in which 2 represents the spools or reels for holding quantities of stranded wire or material 3. There is shown at 4 opposite each of the tensioning reels or spools 2 any suitable tensioning means, such as a pair of drums, around which the stranded wire is adapted to pass. Beyond the tensloning means 4, there is positioned a laying means preferably in the form of annular or ring member 5, through which all of the strands pass in a manner hereinafter to be described. At a point beyond the laying means or annular member 5, there is disposed a haul-off or pulling mechanism 6 for collecting the rope after it is formed.

The stranded wire or material 3 Passes from spools or reels 2 to the respective tensionin means 4 and through the laying means or annular member 5 to the haul-off mechanism 6. It will be understood that the haul-off mechanism pulls the strands 3 from the spools or reels through the tensioning means and through the laying means or annular member 5. There is also pulled thereby through the annular member 5 a center or 'core member 1. which is usually a hemp center and around which the strands 3 are adapted to be arranged. It will be understood that each of the strands 3 pass to and through the form the rope.

Thus, it will be seen that the strands are simultaneously tensioned and twisted around the core or center member at 8 in the annular laying member 5, which is the point of twist. It will be seen that the point of twist 8 of the strands vice.

around the core or center I is at the point the strands 3 and the core or center 1 enter the annular laying member 5, that is at the most forward point of the opening through the annular member as shown'in Figure 2 of the drawings. The tension applied to the strands should be of an amount at least equal to that to which the strands will be subjected when the rope is in use or in other words. the tension should be suflicient to equal the working load of the ropein actual ser- It has been found that the tension applied to each of the strands 3 as they are twisted around the core should be between about 15 per cent and 50 per cent of the breaking strength of each of the strands in order to obtain a satisfactory result. By so applying tension to the strands of the proper amount so as to stretch the same as they are twisted around thecore or centar-member, it has been found that the strands are uniformly and permanently set into position around the core or center member so as to provide a rope having the characteristics of a prestretched rope" whereby any shifting of the strands afterwards relative to each other or to the core member is prevented. Moreover this permits the use of acore of a construction sufflcient to support the steel wire strands of the rope without distorting the core when the rope is subjected to normal loadservice. Such a core construction may be obtained by the use of a core of greater diameter and'weight than cores conventionally used for 'a given size of rope or by the use of a core of the same diameter but harder or denser than conventional cores. Where a fiber core of such a modified construction is selected, this increase of size and weight or hardness or density may be in the. order of at least ten (10) per cent.

Due to the foregoing factors, diameter 6 x 19 type plow grade wire rope, for example, having a fiber center and produced with back ten-" sion within the foregoing limits, has greatly increased resistance to bending fatigue as is clearly shown by the following chart:

Reversals to Pro- 3 Str 7 d B k 1: 50 d an rea mg mas 0 ran Tension Strength Per Cent Increase Over Normal Pounds Per cent 100 234 3 Normal. 300 702 9 6 600 1, 404 18 44%. 2, 106 27 50%. 2, 808 36 44%. 3, 510 46 27%.

The percentage increases in reversals to obtain 50 breaks in the wire of the strands, as shown, were obtained by testing the ropes in a life testing machine in which the ropes were caused to move back and forth over sheaves. The 3 per cent tensions applied to the strands of the rope No. 1 as shown represents the normal tension as used in convention wire rope production. From the chart it is seen that a peak in resistance to bending fatigue is reached with rope produced with back tension in the order of about 25 per cent of the breaking strength of the strands. It was also vfound that rope No. 900 which was laid up with 27 per cent back tension, withstood approximately percent of the number of reversals required to produce 50 breaks in rope No. 100, which was laid up with 3 per cent tensions, before any breaks appeared, whereas the same size rope laid up with normal 3 per cent tensions averaged It will be understood in the present invention that an annular or ring member is employed for guiding and laying the strands to position around the core member. It is the purpose of the annular member 5 to confine the strands I and to provide a point of twist for the strands around the core. As a result it will be seen that the strands are properly laid in place to a substantial degree by reason of the tension applied thereto so as to provide a finished rope of the correct size having a core or substantially heavier weight or greater hardness than normal which will not distort when the rope is put into service.

A wire rope made in accordance with the teachings of the present invention, is shown in Figure 3 of the drawings. In full lines of this figure, there are shown the positions the strands will assume in the finished rope made in accordance with the present invention which is the same position that the strands will assume after the rope is in use. In the broken lines of thisfigure, there are shown the positions the strands will assume in a finished rope made by other methods. Attention is called to the fact that a rope formed by other methods will stretch and diminish in diameter when put into use, and the position of the strands as shown in the broken lines will approach the position shown in the full lines, thereby shifting the strands about the center core and distorting the rope. It will be seen that the position of the strands in the finished rope as formed in accordance with the present invention is the same when formed as when put into service, thereby providing a prestretched rope wherein any shifting of the strands or distortion of the rope is eliminated.

To show more clearl the differences between wire rope formed by other methods and'rope made in accordance with the teachings of the present invention, attention is directed to-Figure 4 of the drawings in which the broken line curve represents a strand in a wire rope formed by other methods and the full line curve represents a strand in a rope made in accordance with my invention or the ideal rope. The pitch of the true or ideal helix of the strand of a rope as shown in full line curve of this figure is represented by P1 and the diameter of the rope by D1. The pitch of the helix of a strand shown in the broken line curve formed by other methods is represented by P2 and the diameter of the rope by De. In methods heretofore used, the strands of the rope shifted from the positions in which they were laid around the core immediately after they had passed through the compression die in fabrication due to expansion thereof. The strands would again shift in position when a load was applied to the rope when in use; that is to say, the strands, when laid by prior methods, would be laid originally so that the helix of each strand assumes substantially the position as shown in the full line curve of Figure 4, but after passage through the compressing die and fabrication of the rope the strands would expand and each strand assumes the position as shown in the broken line curve. Afterwards when a load is applied to the rope when the same is in use the strands again shift and the diameter of the rope diminishes and the helix in the full line curve.

Thus it will be seen that the pitch P: and diameter D2 of the helix as shown in the broken of each strand assumes the position as shown line curve approaches the pitch P1 and diameter Dnoi the true or ideal helix as shown in the full line curve when the finished rope is put into service, thereby distorting the position of the strands. It willbe noted that the pitch of the helices of the strands as formed by the present method is the true helix of the strands and is the same pitch that the strands will assume when the finished rope is in service; that is. the tension applied by the present method should be an amount suiilcient to permanently; set the strands in position around the core or center member so that the pitch of the. helices of each of the strands is uniform and substantially equal to the pitch which the strands will assume when the finished rope is in use.

In Figures 5 and 6 of the drawings, there is shown the apparatus incorporated with a conventional type vertical rope-making machine which may be used for practicing the method in accordance with the present invention. It will be understood that the present method may also be used in connection with stranding machines and the like of-the planetary type. In Figure 5 the cradle assembly and the associated parts of such a rope-making machine, which consists generally of a base Iii upon which there is arranged a bearing l2. There is mounted in the v bearing i2, a vertically disposed mast or shaft i3.

There is carried by the mast is a lower spider member l4 and an upper spider member 15 which are spaced apart from each other. There is concentrically arranged around the shaft or mast i3, between the spiders i4 and II in suitable bearings carried thereby, a plurality of cradles it which are rotatably mounted substantially parallel to the axis of the machine or the mast is and for rotation in a plane substantially parallel thereto in a well-known manner.

By each oi the cradles I6, there is carried a spool or reel I'I arranged in suitable bearings carried thereby, each of which is mounted for rotation on an axis substantially perpendicular to the axes of rotation of the cradles l6 and which is adapted to hold a coil of strand material, such as a coil of stranded wire l8. Below the lower spider it there is arranged suitable gearing for rotatably driving the shaft l3 and the cradles l6, which gearing includes a gear I 9 arranged on shaft is directly below the lower spider it having a drive gear 20 arranged therewith which is adapted to be driven in any suitable manner. There is carried by the lower spider ll, between the. mast i3 and each of the cradles It, a stud shaft 2| having a gear 22 rotatably arranged thereon, each of which is adapted to mesh with the gear is and respective gears 23 arranged on downwardly extending shaft portions 24 carried by the lower end of each of the cradles l6.

According to the teachings of the present invention, there is arranged at a spaced distance above the upper spider Is on the shaft i3, an-

other spider member 2!, and between the spiders,

l5 and 25 there is concentrically arranged in suitable bearings carried thereby a plurality of yokelike members 26 corresponding in number to the number of the cradles I 6 and mounted for rotation on an axis substantially parallel to the axes of the rotation of the cradles and which are adapted to rotate simultaneously therewith. It is preferable that the yoke-like members 26 be made integral with the respective cradles l6, preferably by securely attaching the lower end of the yoke-like members to an upwardly extending shaft portion 21 carried by the upper end of each of the cradles l6 and extending through the upper spider l5. There is rotatably carried by each of the yoke-like members 28, a drum member 28 which is mounted for rotation therein on an axis substantially perpendicular to the axes of rotation of the yoke-like members 26 and the cradles l6 and substantially parallel to the axis of rotation of the spools or reels l'l. I

With each of the drums 28 there is arranged a means for retarding the rotation thereof which preferably consists of a brake 29, or other suitable frictional means, arranged to one side of the drum. This brake consists preferably of an annular member 30 consisting of two halves which are suitably lined with a brake lining, with the halves being pivotally attached together by means of pin 3| to one side of the drum and having a bolt 32 arranged through the ends of the halves on the opposite side thereof with a compression coil spring 33 carried by the bolt for yieldably' holding the two halves of the brake around the drum.

There is arranged above the spider 25 a thrust bearing 34 for supporting the upper end of the mast or shaft l3, and there is arranged beyond the thrust bearing a laying means, preferably in the form of an annular or ring member for guiding and laying the strands in position to form the rope. There is provided a. haul-off or reeling means (not shown) for collecting the rope after it has been formed. a

In the practice of the present invention, the stranded wire l8 passes from each of the reels ll to their respective drums 28 carried by the yoke-like members 26. The wire strands are passed around the drums 28 and then pass preferably over an idling or guide pulley 35, and then to and through the annular laying member 5 where they are laid around the core or center strand 1 and the formed rope then passes to the head of the machine, from which pointthe completely formed rope is directed to be reeled or coiled. It will be understood that the strands are pulled through the annular laying member 5 from the reels I! by the haul-off mechanism,.and it is the purpose of the drums 28 to place the strands under tension as they pass therearound and are being pulled therefrom. The drums then become a constant speed, back-tensioning or payoff mechanism which allows the strands to be paid off in a uniform manner. g

Thus, it will be seen that as the strands pass to the annular laying member, they are under tension, which causes the strands to be set down into place firmly at the point of twist, namely, at the entrance or inner end of the laying member.

It will be understood that the tension applied to the strands can be adjusted by manipulating the nuts carried by the bolts 32 so as to equalize the tension on all of the strands. While a braking mechanism has been shown for retarding the rotation of the drums, it will be understood that any other suitable means may be provided for retarding the motion of the same. It is desirable that the drums be arranged so that tensions greater than approximately 15 per cent of the breaking strength of the strands can be applied thereto, thereby forcingthe strands down into position in the formed rope under conditions to which they are subjected when in use in the finished rope.

In Figure 6 of the drawings, there is shown a slight modification of my invention. In this construction, there is provided a Pair of drums 28 oppositely disposed from each' other. It may be desirable to use such a construction so as to assure a more uniform tension on the strands, or where a large rope is being formed from relatively large strands. As before, the strands pass from the cradles over and around both the drums, preferably several turns therearound, over the idling sheave 35 and to the annular laying member 5.

It will be understood that the tensioning means, namely the drums 28, are made an integral part of their respective" cradles and are adapted to rotate therewith, and apply a uniform tension to all of the strands thereby obtaining a finished rope product with the strands properly laid in position therein so as to provide a rope having the characteristics of a prestretched rope.

As a result of my invention, it will be seen that there is provided an improved method of manufacturing rope whereby there is provided a finished rope having all the attributes that a rope should have, thereby eliminating the disadvantages in a rope as made by methods heretofore employed. It will also be seen that there is provided an improved apparatus for practicing the method of the present invention which is not only simple and inexpensive in its construction but also eflicient and effective in its use.

While I have shown and described one specific embodiment of my invention, it will be understood that this embodiment is merely for the purpose of illustration and description and that various other forms may be devised within the scope of my invention, as defined in the appended claims.

I claim:

1. In the manufacture of wire rope having a core member with a plurality of twisted steel wire strands helically arranged therearound, the method consisting of pulling the core and strands in one direction by forward tension, applying back tension uniformly to the strands as they are being pulled forwardly, and providing a point of lay intermediate the points of forward and back tension, said back tension being at least 15 per cent of the breaking strength of the strands to thereby set the strands down firmly at the point of lay to a substantial extent by radial forces which are the components of the tensions applied'to the respective strands.

2. In the manufacture of wire rope having a core member with a plurality of twisted steel wire strands helically arranged therearound, the method consisting of pulling the core and strands in one direction by forward tension, applying back tension uniformly to the strands as they are being pulled forwardly, and providing a point of lay intermediate the points of forward and back tension, said back tension being between 15 and 50 per cent of the breaking strength of the strands to thereby set the strands down firmly at the.

point of lay to a substantial extent by radial forces which are the components of the tensions applied to the respective strands.

3. In the manufacture of wire rope having a core member with a plurality of twisted steel wire strands helically arranged therearound, the

method consisting of pulling the core and strands in one direction by forward tension, applying back tension uniformly to the strands as they are being pulled forwardly, and providing a point of lay intermediate the points of forward and back tension, said back tension being about 25 per cent of the breaking strength of the strands to thereby set the strands down firmly at the point of lay to a substantial extent by radial forces causes which are the components of the tensions applied ,to the respective strands.

4. In the manufacture of wire rope having a fiber core member with a plurality of twisted steel wire strands helically arranged therearound, the method consisting ofpulling the fiber core and strands. in one direction by forwardtension, said fiber core being substantially thicker than the core normally used, applying back tension uniformly to the strands as they are being pulled forwardly, and providing a point of lay intermediate the points of forward and back tension, said back tension being between 15 and 50 per cent of the breaking strength of the strands to thereby set the strands down firmly'at the point of lay are the components of the tensions applied to the respective strands.

to a substantial extent by radial forces which I 5. In the manufacture of wire rope having a fiber core memberwith a plurality of twisted steel wire strandshelically arranged therearound, the method consisting of pulling the fiber core and strands in one direction by forward tension, said fiber core being substantially thicker than the core normally used, applying back tension uniformly to the strands as they are beingpulled forwardly, and providing a point of lay intermediate th points'of forward and back tension, said back tension being about 25 per cent of the breaking strength of the strands to thereby set the strands 'down firmly at the point of lay to a substantial extent by radial forces which are the components of the tensions applied to the respective strands.

6. In the manufacture of wire rope having a 35 Number fiber core member with a plurality of twisted steel wire strands helically arranged therearound. the

method consisting of pulling the fiber core and strands in one direction by forwardtension. said fiber core being substantially harder than'the core normally used, applying back tension uniformly to the strands as they are being pulled forwardly, and providing a point of lay intermediate the points of forward and back tension, said back tension being'about 25 percent of the breaking strength of the strands to thereby set the strands down firmly at the point of lay to a substantial extent by radial forces which are the components of the tensions applied to the respective strands.

7. As a new article of manufacture, a wire rope produced in accordance with the method of claim 1. I

8. As a new article of manufacture, a wire rope produced in accordance with the method of claim 2.

9. As a new article of manufacture, a wire rope produced in accordance with the method of claim 3. j

10. As a new article of manufacture. a wire m rope produced in accordance with the method of claim 4.

11. As a new article of manufacture, a wire of claim 6. A

- EUGENE J. REARDON.

REFERENCES crrEn The -following references are of record in the file of this patent:

UNITED STATES PATENTS Name Date 723,806 Avis Mar. 31, 1903 1,078,073 Tobey Nov. 11, 1913 1,422,073 Anderson July 11, 1922 2,037,506

'Ensinger et a1. Apr. 14, 1936