US1558420A - Rope structure - Google Patents

Description

H. V. WHITLOCK ROPE STRUCTURE Filed Dec. 30 1924 3 WiWEZM ATTORNE Patented Oct. 20, 1925.

UNITED STATES PATEN'E OFFICE.-

ROPE STRUGTURE.

Application filed December 30, 192;. Serial No. 758,805.

To at? 20710722 it may concern: i

Be it known that I, HERBERT VERNET \VHITLOCK, a citizen of the United States. and a resident of Elizabeth, county of Union, and State of New Jersey, have invented'certain new and useful Improvements in Rope Structures, of which the following is a specification.

The present invention relates to rope structure and particularly to a new and improved form of strand structure for ropes that is-cheap and simple to manufacture as compared with ropes of the prior art, that has tensile strength, wearing qualities and durability substantially in excess of ordinary rope, and that provides many advantages in use and in handling. v

The present application constitutes an improvement on the subject matterdescribcd in my Patent Numbered 1,442,790, and covers a specific form of the broad-invention therein disclosed which has certain advantages in manufacture and in use oyer the particular embodiment of the invention described in that patent.

Heretofore the manufacture of rope has ordinarily consisted of a number of different stages. First, the preparation of the sliver comprising a. continuous band made up of fibers combed and recombed so as to lie side by side in parallel relation. The

fibers of manila or sisal from which rope. is ordinarily made vary from. 8 to 12 feet in length. The sliver has no tensile strength in lengths in excess of 10 or 12 feet for tension simply draws the fibers apart and there is no compression and hence no friction as between the fibers to resist their relative longitudinal movement. The next step in rope construction is to spin the sliver into the yarn. This is done by simultaneously drawing and twisting the sliver to form a yarn of uniform diameter wherein the fibers are tightly twisted about the axis of the yarn and the compression .of fiber on fiber by reason of this twisted relation sets up a frictional resistance to'longitudinal movement as between the fibers so that the yarn thereby achieves tensile strength. The next step is forming the strand of a multiplicity of yarns, the number of yarns depending upon the desired size of the strand to be formed. The several yarns are twisted together in the strand-forming machine, those yarns at the outside of the finished strand being called the cover yarns, and those inside being called the inner or core yarns. Finally, three or more strands so formed are laid or twisted together to form the finished rope.

In strands so formed it will be apparent that the core structure [comprises fibers comprising astrand are of different length,

the outside yarns being longest and those nearest the axis of the strand being shortest. \Vhen tension is put upon a rope comprising such a structure,there is immediate tendency of the various parts to move rela-. tively to one another. Each elementof the rope as it is stretched lengthwise tends to move toward the axis of the rope, and there is simultaneously a tendency to untWist. Accordingly very heavy strains are brought to bear at the contacting pointsof adjacent yarns throughout .the rope structure, and, as pointed out above, this results in crossrubbing of fiber on fiber with resulting tendency to rip and shear the fibers. Furthermore, the diversity in length of yarns results in bringing the greatest pressure first on the innermost yarns and the greatest tendency to rip and shear at that point, so that, as is well known, ropes of ordinary structure tend to rupture at the center first and from the center outwardly.

I havev found that by omitting entirely the step of spinning into yarns the slivers that are to constitute the core of the rope, and by employing in place of the core yarns a number of slivers containing substantially fit) the same quantity of fiber and by twisting the slivers together and at the same time covering the same with a continuous protective covering of yarns, I am able to provide a rope structure which is not only simpler and cheaper to manufacture than ordinary ropes, but is actually stronger, more durable,. easier to handle, and has better wearing qualities than the ordinary rope referred to.

In my Patent No. 1,442,790, I have disclosed and claimed my broad invention and illustrated the same by reference to one specific embodiment thereof wherein the strand structure has been so fabricated that before the strands are laid into the rope, the fibers constituting the core of each separate strand are straight and parallel to one another.

That specific 'form of the invention, however, is relatively costly and diflicult to manufacture because in order that the core of fibers may be s ubstantially straight in the finished strand, the supply of slivers to the strand forming machine must be rotated insynchronism with the rotation of the winding drum of the forming machine or else the supply of cover yarns must be rotated relatively to the winding'drum, or other appropriate means employed for the purpose.

In my present invention I prepare the sliversin exactly the same manner in which they have previously been prepared for spinning into yarns. The slivers are then conveyed to the forming machine in any appropriate manner, for example, as shown inv the application of Walter L. Faust, Ser. No. 697,245, filed March 6, 1924, or otherwise; Their ends are then brought together to form the coreand are threaded as a unit into the forming machine. The cover yarns is thereby produced in which the core fibers are twisted about the axis of the strand, each fiber forming substantially a helix, and

the pitchof each helix being substantially equal to. the pitch of the helices formed by the covering yarns. In strand structures so formed it will be apparent that the core fibers lie side by side in substantially con tinuous longitudinal contact with adjacent fibers throughout their length, and that the resistance to longitudinal strain will be by friction between fibers lying side by side as contradistinguished from friction of'fiber rubbing across fiber.

It will be understood that three or more strand structures so formed may be. laid. into rope in the usual manner.

Very substantial savings-and advantages occur in themannfacture of the rope here-- in described over ordinary ropes of the prior artand also over ropes constructed Upon rotation of the as shown in my patent above referred to. An additional advantage of my present invention is that it enables me .to convenient- 1y coat or impregnate the core fibers with lubricating or damp resisting material or other preservative which gives added wearing qualities and greater durability to the finished rope. This may be accomplished by passing a number of the slivers through a trough or other vessel containing the lubricating or damp-resisting material or the like in liquid form immediately before the same are led into the strand forming machine in company with the other slivers to form the core. As the slivers are twisted in the strand forming operation and squeezed by the winding on of the cover yarns, the liquid material is uniformly disseminated through the core and highly desirable qualities thereby given to the rope as a whole.

In all-yarn ropes of the prior art it has been customary to pass a number of the core yarns through such a liquid material before the strand forming operation, but on account of the tightly twisted fiber structure of such yarns the liquid material does not penetrate substantially below the cover fibers thereof and when the coated yarns are twisted into the strand, the dissemination of preservative material is Very limited; so that on later examination of the strand the pre-coated yarns are clearly distinguishable from the rest, while the remaining yarns. are practically untouched by the preserva-.

tive material. In my invention, however, the fiber structure of the slivers being relatively loose at the moment of addition of the particular slivers carrying the preservative material, the same is permitted to spread through the other fibers going to make up the core and is quiteuniformly disseminated therethrough as the corefibers are twisted in the strand forming machine.

Aside from the advantages of cheapness and simplicity of manufacture referred to. my rope structure made according to this invention has many advantages over ordinary rope as well as over rope structures in which the core fibers lie substantially straight and parallel to the axis of the individual strands. \Vhen astrand made in accordance with my present invention is placed under tension. there is an immediate compression of the core fibers on account of their twisted relation. Each core fiber. due to its helical form, tends to move toward the axis of the strand and so compress the fibers lying between it and the axis. Compression is thereby at once set up throughout the entire core structure. and longitudinal slippage of fibers is substantially prevented. In rope structure wherein the fibers of the core lie substantially straight, there is no such compression tendency in the core itself, and the compression necessary to overcome sllppage 1s provided only by the cover yarns .or, where the strands have been laid into a rope, by the twisted relation of the several strands. As compared with the rope described in my prior patent, therefore, the present invention While allowing desired elasticity, prevents to a large degree any permanent stretch and elongation of the rope structure.

As compared withordinary rope made up of twisted yarns, my present invention provides much greater tensile strength because the core fibers lying side by side produce a uniform compression and friction throughout the length of the fibers without cross-rubbing as contrasted with the localized and intensifiedfriction and cross-rubbing inherent in ordinary ropes of the prior art, so that-by my invention the core fibers-cooperate'to reenforce each other instead of tending to ripand shear each other, so that as a result my rope is able to operate more as a unit and it hasbeen demonstrated bybreaking tests that whereas ordinary rope ruptures yarn by yarn from the center to the outside, the rope of my present invention is capable of resisting much greater tensile. strains and ruptures all at once when the limit of its tensile strength'is reached. -Be- 'a'core of fibers and a continuous covering low that point I have not found any evidence t rupture of any part of the-rope either at the center of the cores -or else-- where.

Another practical advantage of my present invention over the specific form shown in my Patent No. 1,442,7 90 lies in-the fact that when the rope of my present invention f is used for marine purposes or the like, the greater core compression due tothe twisting of the core fibers tendstoprevent water from entering the rope' structure and tends to squeeze-out any water already there, so that the rope structure is. less likely to become water-logged and stifi' and hence is easier to handle and less likely to rot.

Other advantages of my present invention: will be apparent from the following description taken in connection with the accompanying drawings, in which Fig. 1 shows in elevation a portion of rope structure embodying my present invention, one of the strands being frayed. to show the structure of the core, and in which Fig.2 shows a:

cross section ,of the rope structure.

In the drawings, three strands, 1, 2- and'3 are shown laid together to form a rope such;

as a marine hawser .or the like. The strand 1 is frayed at its lower end to show that it consists of a core 5 and a series of cover.

yarns 6. The cover yarns are '.helically wound about the core to provide a continuous covering therefor, and it will be seen that the strands 2 and 3 are similarly provided with a continuous covering of yarns.

WVhile my present invention makes use of one of the fundamental advantages of the rope disclosed in my patent in that the fibers of the core lie side b side throughout their length so that each fiber is substantially in continuous longitudinal contact with the vfibersthat are adjacent to it on every side,

it will be apparent that important advantages both in manufacture and in use are addedtliereto by the present invention.

, While I have described my invention by.

reference to aspecific. embodiment thereof, it is to be understood that this description is illustrative merely and isnot intended to limit the invention described in the 'appended. claims.

What I claim is: I J 1. 'In rope structure, a strand comprising ofyarns,the said fibers lying substantially in helices about theaxis of the said strand.

-2.' In rope structure, a strand comprising a core of fibers and a continuouscovering of yarns, thesaid fibers lying substantially in helices about the axis of the said strand,

a core and a continuous covering of yarns,

the said. core containing fibers lying sub stantially in helices about'the axis of the strand.

"5. In rope structure, a strand comprising ,a wear-resisting-covef anda tensile core,

said core being characterized by fibers lying side by side in substantially continuous longitudinal contact and forming helices about the axisof the said strand.

.6. In strand structure, a tensile core of unspun fibers, said fibersbing in simple twisted relation about the axis of the strand, and each. fiber lying in substantially continuous longitudinal contact with adjacent fibers throughout its length, the said fibers cooperating by reason of their relation to resist tensile strain.

, -7. In rope structure, a strand comprising a core and a protective covering of yarns,

the core being characterized by fibers lying substantially in helices about the axis of the strand. p

8. In rope structure, a fiber 'core containing fibers lying side by side in substantially continuous longitudinal contact, the said fibers being coated with lubricating material. v

9. In rope structure, a strand comprising a wear-resisting cover and a tensile core, the said core containing fibers twisted about the axis of the core, the said fibers being-coated with preservative material. a

10. In rope structure, a strand, a core therefor made up of fibers, the fibers being uniformly coated with preservative material.

11. A rope structure including a strand having a single core of fibres spirally twisted about a common axis, and cover yarns strand fibres and in the same direction as the direction of twist of the strand fibres.

13. In rope structure, a strand comprismg a core and a contlnuous covering of yarns, said core containing fibers lying substantially in helices about the axis of'the strand and the pitch of thesaid helices being substantially the same as the pitch of the helices formed by the covering of yarns.

In testimony whereof, I have signed my name to this specification.

HERBERT VERNETWVHITLOCK.

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