US2771315A

US2771315A - Hoisting sling

Info

Publication number: US2771315A
Application number: US489138A
Authority: US
Inventors: Francis F Fenwick
Original assignee: Individual
Current assignee: Individual
Priority date: 1955-02-18
Filing date: 1955-02-18
Publication date: 1956-11-20
Anticipated expiration: 1973-11-20

Description

F. F. FENWICK HOISTING SLING Nov. 20, 1956 2 Sheets-Sheet 1 Filed Feb. 18, 19,55

' INVENTOR.

fiaiygia .1 evn zc i5 BY F. F. FENWICK HOISTING SLING Nov. 20, 1956 2 Sheets-Sheet 2 INVENTOR. fiavgfs if e 1 Filed Feb. 18, 1955 United States Patent-O HOISTING SLING Francis F. Fenwick, South Orange, N. .1.

Application February 18, 1955, Serial No. 489,138

6 Claims. Cl. 294-74 This invention relates to improvements in slings adapted to be detachably engaged with the lift hook of hoisting or like goods handling and transporting mechanism.

In the handling and transfer of various goods, articles or objects desired to be moved from one place to another by hoisting or like handling mechanism, there is demand for a supporting sling having loop ends adapted to be engaged by the lift hook of the hoisting or like handling mechanism, the sling being made of relatively nonabrasive material so as to avoid marring or defacement of the goods, articles or object to which it is applied in use. To meet this demand, slings have been produced from flat strips or bands of relatively non-abrasive material, such as strips or bands of leather or like non-woven material, or from woven fabric webbing, the latter appearing to be the most satisfactory material and to best enjoy popular acceptance. Heretofore in the construction of such type of sling, the loop ends thereof were formed by doubling back the end portions of the strip, band or webbing, and then stitching the free end of the doubled back leg of the loop to the body of the strip, band or webbing. Such construction is not entirely satisfactory for the reason that, when subjected to wear in use, the stitching is likely to part with risk of breaking away of the leg of the loop from the body of the strip, band or webbing with consequent opening out of the loop so as to escape from the hoisting hook with which it is engaged with resultant freeing of the object being handled from the sling applied thereto, thereby involving risk of serious injury to said object.

Having the above in view, it is an object of this invention to provide a sling having novel loop end structure, and method of producing the same.

Another object of the invention is to provide a novel loop end structure for a sling, said loop end structure having self-contained means for anchoring the same to the body of the sling, said anchoring means being of such character that no stitching together of parts thereof is required.

A further object of the invention is to provide loop end structures for a sling which include integral means for joining the legs of the loops to the body of the sling, whereby the resultant jointure is of great strength, and, under pulling tension exerted by the weight of an object supported by the sling, can not loosen, but on the contrary increases its resistance to pulling or opening out of the loop formation under pulling stress.

The above and other objects of this invention will be understood from a reading of the following detailed description of said invention in connection with the accompanying drawings, in which:

Fig. l is an edge elevational view of a hoisting sling provided with the novel loop end structures according to this invention; and Fig. 2 is a side elevational view of the same.

Fig. 3 is a fragmentary face view of an end portion of a strip or band as prepared ready for manipulation to provide the same with a loop end structure according to 2,771,315 Patented Nov. 20, 1956 this invention; Fig. 4 is a central longitudinal sectional view of the strip or band of Fig. 3, with the free end part thereof folded upon itself ready for further manipulation to form the loop end structure therefrom; Fig. 5 is a side edge elevational view of a loop end structure formed from the folded end part of the strip or band shown in Fig. 4; Fig. 6 is a face view of the formed loop end structure; and Fig. 7 shows the jointure between the loop end and body of the sling as preferably enclosed within an encasing sleeve of resilient material such as rubber or the like.

Fig. 8 is a fragmentary view similar to that of Fig. 1, but showing the loop forming section of the sling body folded crosswise upon itself and suitably secured to provide a loop of double thickness; and Fig. 9 is an edge elevational view of a loop end structure produced from the loop forming section of Fig. 8.

Referring to the drawings, in which like characters of reference indicate corresponding parts, the sling is produced from a flexible strip or band of suitable woven or non-Woven material, and of selected length, width and thickness. A satisfactory material, which provides a sling of desired relatively non-abrasive character, comprises a length of webbing of selected width and thickness Woven from suitable textile or synthetic fibre strands, the mid portion of said length of webbing constituting the body 10 of the sling. As shown in Fig. 3, formed in each end portion of the body 10, intermediate the side edges thereof, are a pair of longitudinally spaced apart slits 11 and 12 of suitable length. The outer slit 11 is spaced inwardly from the extremity of the end portion, whereby to provide, between said slit 11 and said extremity, a lap tongue 13. The slits 11 and 12 are spaced a distance apart calculated to provide therebetween a loop forming section 14 of suitable length. The slit 11 divides the webbing into separated sections a and a respectively bordering opposite sides of said slit, and, in like manner, the slit 12 divides the webbing to form separated sections b and b respectively bordering opposite sides of this slit.

To produce a loop end structure according to this invention, the loop forming section 14 is folded longitudinally upon itself midway between the slits 11 and 12 in such manner as to register together the slits 11 and 12 in mutually aligned relation, and so that the bordering sections a and b along one side thereof and the bordering sections a and b along the opposite side thereof, are brought into superposed, face to face, contiguous relation. At the same time the lap tongue 13 laps the body 10. Such preliminary manipulation of the webbing forms an end loop 15 (see Fig. 4).

The end loop 15 is now ready to be manipulated whereby to close the same and integrally join it in interlocked relation to and for extension from the body 10. To accomplish thisthe closed outer extremity of the end loop is swung down and passed through the aligned slits 11 and 12, and then swung up to its normal outwardly extending position. This manipulation is performed at least once, but preferably two or more times. As shown in Figs, 5 and 6, such manipulation has been performed twice. By such manipulation, the contiguous superposed sections a and b at one side of the slits, and the contiguous sections a and b at the other side of the slits, are each twisted together so as to respectively form intertwined helical convolutions 16 and 16', thus interlocking said sections a and a and b and b together in jointure structure which both closes the end loop 15 and, at the same, strongly connects the same in operative extension from an end of the body 10 of the sling.

It will be observed that the jointure structure thus produced connects each loop end structure to respective ends of the sling body 10 by a fastening arrangement which is integral with both the loop end structure and the sling body. By reason of this, the jointure partakes of the tensile strength of the entire webbing of which the sling is made, and since no independent or separate fastening means, such as stitching, is required to close the loop end structure in attached relation to thesling body, risk of'loosening or parting of the loop end structure under pulling stresses and strains, to which the sling is subjected in use, .is eliminated. In fact, under applied pulling stresses and strains, the helical convolutions of the twisted together sections a and b and z." and b tend to tighten upon themselves with intengripping .and binding effect which increases proportionally to the amount of pulling stress or strain applied thereto. This condition coupled with the additional condition that the twisted together sections a and b and a and I) possess no free ends, since their upper ends join the legs of the end loop 15 and their lower ends join the superposed lap section 13 and body of the sling, assures an exceedingly strong jointure of an end loop structure to the sling body which can not loosen or pull apart.

Although it is not essential, it is desirable to enclose the jointure formed by the helical convolutions 16 and .16 in a restrictive covering which encloses the latter and compresses them into contiguous side by side relation. To this end, a sleeve 17 of elastic material, such as rubber, can be drawn over the loop end structure into encasing relation to the jointure thereof with the 'slingbody.

Referring now to Figs. 8 and 9, there is shown therein a modification of the above described loop end structure whereby the end loop thereof is stiffened and reenforced by forming the same of double thickness, and thereby expanding the loop eye thereof. To efiect this,'the loop forming section of the webbing, or other strip or band from which the sling is produced, is folded crosswise upon itself before it is longitudinally folded or doubled back upon itself to form an end loop. Such cross folding of the loop forming section provides an end loop forming portion 14 of double thickness and one-half the width of the webbing strip. The superposed cross folds thus produced are then secured together against unfolding by stitching 18. This having been done, the

'loop forming portion 14' is longitudinally folded upon Having now described my invention, I claim:

1. A'hoisting sling comprising a'body provided'bya strip of flexible material of selected length, width and thickness, said body having inwardly of its respective extremities a pair of longitudinally spaced apart slits, disposed intermediate and parallel to its side edges whereby to form separated sections bordering opposite sides of the respective slits, each "end portion of the body being longitudinally folded ;upon itself midway of said slits therein, to form an end loop and so as to register said slits in opposed aligned relation'withbordcring sections at corresponding ,sides thereof disposed in contiguous face to face relation, and said'respective face to face bordering sections being twisted upon themselves by rotating the end loop through said slits thus forming therein intertwined helical convolutions which unite the legs of the end loop in closed together and secured relation to .the sling body.

.2. A hoisting sling according to claim 1 wherein the body strip comprises-a woven fabric.

3, A hoisting sling according toclairn 1 including a sleeveof elastic material enveloping said helically intertwined slit bordering sections. 1

4. Ahoisting sling comprising a body provided by strip .of flexible material of selected length, width and thickness, said body having inwardly of its respective extremities a pair of longitudinally spaced apart slits disposed intermediate and parallel to its side edges whereby .said slits thus forming thereinintertwined helical convolutions which unite the legs of the end loop in closed together and secured relation to the sling body.

5. A hoisting sling according to claim 4 wherein the body strip comprises a woven fabric.

6. A hoisting sling according to claim 4 including a sleeve of elastic material envelopingsaid helically intertwined slit bordering sections.

No references cited.