US3325990A

US3325990A - Ropes and methods of making the same

Info

Publication number: US3325990A
Application number: US369241A
Authority: US
Inventors: Remo J Laureti
Original assignee: Wall Rope Works Inc
Current assignee: Wall Rope Works Inc
Priority date: 1964-05-21
Filing date: 1964-05-21
Publication date: 1967-06-20
Anticipated expiration: 1984-06-20

Description

June 20, 1967 R. J. LAURETI RQPES AND METHODS OF MAKING THE SAME Filed May 21, 1964 FIG.

FIG. 3.

FIG. 2.

III IIIII III FIG. 4.

INVENTOR RENIO J. LAURETI ATTORNEYS United States Patent Jersey Filed May 21, 1964, Ser. No. 369,241 3 Claims. (11. 57-144 This invention relates to ropes and methods of making the same and has particular reference to ropes resistant to hockling. The term ropes as used herein includes what are technically known as ropes, cables, and other cordage involving twisted or laid strands.

Ropes which have been abused by kinking or the like are subject to what is known as hockling which may be generally described as involving displacement of component yarns of a strand out of their proper relative positions. Layered strands are particularly susceptible to this condition and the outstanding characteristic which appears is that of protrusion or exposure of one or more inner layers through openings between adjacent yarns of the outermost layer, the outermost layer being, in effect, opened up by reversal of its twist, which outer layer would ordinarily cover the next inner layer. Once this protrusion occurs the lay of the strands is so disturbed that the rope is weakened and its service life is shortened. Hockling also produces bulging preventing the rope from running through blocks and tackles. Since disturbance of the layers of a rope is resisted to a considerable extent by friction, a low coefficient of friction of the rope components leads to a greater tendency toward hockling, and consequently this is a matter particularly encountered when the ropes are made of synthetic filaments and partially those having low coefficients of friction such as polypropylene and polyethylene filaments.

The general object of the present invention is to improve the hockling characteristics of ropes by shrouding the portions of a strand inward of an outer layer of yarns by means of a confining sleeve which, while having negligible contribution to the tensile strength of a rope will sufiice to prevent inner yarns from protruding through an outer layer, While, therefore, the outer layer of yarns may become displaced under conditions which would otherwise give rise to hockling the application of tension to the rope in use will generally restore to a satisfactory degree the placement of the yarns of the outer layer to the extent that the strength of the rope is not unduly impaired.

The foregoing general object of this invention together with other objects relating to details and to methods of manufacture will become more apparent from the following description, read in conjunction with the accompanying drawing in which:

FIGURE 1 is a diagrammatic view, partially in section, illustrative of one procedure for manufacturing a rope strand in accordance with the invention;

FIGURE 2 is a cross-section illustrating the makeup of a strand provided in accordance with the invention;

FIGURE 3 is a cross-section of a rope formed by the laying of strands of the type illustrated in FIGURE 2; and

FIGURE 4 is a view similar to FIGURE 1 but showing an alternative manufacturing procedure.

FIGURE 1 illustrates a preferred procedure for the manufacture of a strand 2 which is to be later laid into a rope or cable. The procedure involves what essentially amounts to only an added step in the formation of a strand in conventional fashion and consequently details of the complete twisting and layering procedure are not illustrated and need be described only briefly.

As is usual, the component yarns which may be singles or plied yarns are fed from supplies through guides (not shown) and are compacted by a guide or forming tube 6 having a flaring receiving end, twisting being effected by the rotation about the axis of the strand of rotating capstans and the receiving creel. Differing from the conventional procedure, the component yarns which enter the guide 6 and are twisted therein are only those of the inner layers, excluding those forming the outer layer as described later. The guiding is accomplished in the usual fashion to produce layering, the number of layers involved depending on the size and desired structural composition of the rope. Emerging from the guide 6, therefore, is the layered portion 8 of the strand without its ultimate outer layer of yarns.

Beyond the end of the guide 6 a tape 10 is fed from a supply reel and guided at a suitable angle through a slot or other guiding arrangement which is not shown. This tape is fed at such an angle, that, considering its width, its adjacent convolutions produced about the strand portion 8 and indicated at 12 overlap slightly, though as an alternative the tape 10 may be wound about the portion 8 with the convolutions non-overlapping but sufficiently close together as to confine satisfactorily the yarns of the portion 8.

The tape 10 is merely a confining element and by being tightly 'WOUIlCl, for example by reason of the application of a brake to the supply reel, it will exercise its confining action even without the exertion of great tension thereon. It may, accordingly, 'be of a material having relatively low strength. For example, the tape may be of a thin and loosely woven fabric of any desired textile material though for good resistance against deterioration by moisture it is desirably woven of synthetic fibers such as of nylon, or the like. Alternatively, it may be formed of a braided material of the same type of composition. The tape may also be quite inexpensively formed as a flattened tube of a circularly knit material such as nylon, and if this type of tape is used the knitting may be quite loose with large loops so that a minimum weight of material may be used for a given length. Still further, the tape may be formed as an open work extruded net of a plastic material such as polyethylene or polypropylene. The tape may even be provided merely by running, in parallel unconnected yarns to form multiple helices about the strand portion 8. The feed is desirable at a steeper angle than that of the twist of the outer layer of the strand portion 8 so that its helix angle is greater than that of that layer.

While not generally essential, an adhesive may be applied to the tape to keep its adjacent convolution in definite fixed relationship to each other so as to avoid any possibility of shift of positions which might expose objectionable portions of the outer layer of the component 8. Most desirably used is an adhesive of the type having permanent tackiness, such as that used for medical bandages. It is also advantageous to use a tape having such an adhesive on both faces so as to bind to the barrier tape both the inside and outside yarns.

The wrapped portion 8 of the strand then feeds through a second guide 13 which also receives the yarns 14 of the outermost layer of the strand 2, this layer being indicated at 16. The finished strand which is then reeled up presents an external appearance and configuration corresponding to that of a conventional strand.

FIGURE 2 indicates the finished strand showing the relationship of its component elements. Three such strands may then be laid in conventional fashion to form a rope 18 and it will be obvious that variations may here be involved in conventional fashions to provide cables or other types of cordage.

The improved resistance to hockling will be apparent from the foregoing. Even if the yarns used are of such materials as polypropylene or polyethylene having low coeflicients of friction, and even though abuse of the rope tends to untwist the outer layer, the yarns of the inner layers are unable to protrude through the outer layer.

The tendency to break the wrapping 12 under conditions which would ordinarily give rise to hockling is quite low and for this reason, as indicated above, the tape need have very little tensile strength. The outer yarn layer of the strand protects it against damage by abrasion. As will further be evident it plays no appreciable part in contributing to the strength of the strands or rope due to tension, yielding readily to such displacements as may occur due to stresses without deterioration of its confining function.

FIGURE 4 illustrates an alternative in which the confining wrapping is not a helical wrapping but is tubular and provided by a knitted or braided tube. The procedure in accordance with FIGURE 4 is the following:

As in the case of what is illustrated in FIGURE 1, the component yarns 28 of the strand, with the exception of those to form the outer layer are fed from conventional supplies and guiding means into the flared end of a guide which is extended as a tube 22 which may be of considerable length as indicated by the break at 24. Before the formation of the strand is begun there is located on the tube 22 what may be a quite long length of the sleeveforming tubular fabric. If this is of loosely knit or braided type, this length may greatly exceed the length of the tube by pushing it thereon in a corrugated fashion as indicated, the tube 26 being thereby bunched on the tube 22.

The fabric tube 26 is drawn off the end 30 of the tube 22 whereupon it collapses as indicated at 32 and the inner portion of the strand formed from the yarns 28, and desirably it may be fed through a fixed rubber or similar guide 34 applying friction so that it is drawn out as it is pulled forwardly. Placed about it thereafter are the yarns 36 to form the outermost layer which are twisted over the wrapping with compacting by the guide 38. The finished strand 40 like that shown in FIGURE 2 presents exteriorly the outermost layer of yarn and differs from the strand previously described only in that the wrapping of the inner yarns is by the tube .26 rather than by a helix of tape. The characteristics of the resulting strand are the same as previously described, the strands thus produced being laid into rope or cable.

It will be evident that the tube 26 instead of being woven or braided may be produced by stitching into the form of a tube a folded woven tape. As another alternative, an extruded net of polypropylene or polyethylene or other plastic material may form the tube.

It will be evident that various details of manufacture and construction may be modifiedwithout departing from the invention as defined in the following claims.

What is claimed is:

1. Cordage comprising twisted strands formed of assembled layers of yarns having a tubular, helically wound fabric member on which the outer layer of yarns is wound, said fabric member being coated on one side with an adhesive material and said tubular member confining the assembly of inner layers, said helically wound fabric member being wound at a helix angle such that adjacent convolutions of said fabric member overlap and adhere to one another.

2. Cordage comprising twisted strands formed of assembled layers of yarns having a tubular, helically wound fabric member on which the outer layer of yarns is wound, said fabric member being coated on both sides withan adhesive material and said tubular member confining the assembly of inner layers, said adhesive material causing said tubular member to adhere to said inner and outer layers.

3. The method of making a layered strand for assembly into cordage which comprises first twisting yarns to form the inner layers of the strand, locating over said twisted yarns a tubular confining member by helically winding over said twisted yarns a fabric tape coated on at least one side with an adhesive material, and then twisting over said confining member yarns to form an outer layer of the strand.

References Cited UNITED STATES PATENTS 1,686,098 10/1928 Meiwald 57-144 X 1,900,041 3/1933 Brodhun 57-144 X 2,022,683 12/1935 McKinnon et a1 57-144 2,022,690 12/1935 Reed 57-144 2,041,418 5/1936 Katz 57-150 2,087,303 7/1937 Rosch et al 57-144 X 2,096,606 10/1937 Buhler 57-149 2,145,153 1/1939 Cristiansen et al. 57-144 X 2,146,966 2/1939 Lilley 57-149 2,200,933 5/1940 Nystrorn et al. 57-138 X 2,203,232 6/1940 Osborne et al 57-150 2,203,622 6/1940 Van Voorhis 57-144 2,204,776 6/1940 Schifrin 57-144 2,250,776 7/1941 Sackner 57-150 2,254,762 9/1941 Thiel 57-162 2,262,017 11/1941 Lilley 57-149 2,558,855 7/1951 Knewstubb et al. 57-149 X 3,106,815 10/1963 Nance et al. 57-138 FRANK J. COHEN, Primary Examiner.

D. E. WATKINS, Assistant Examiner.