US3317233A

US3317233A - Sling construction and method of making same

Info

Publication number: US3317233A
Application number: US449453A
Authority: US
Inventors: Boyd C Black
Original assignee: Individual
Current assignee: Individual
Priority date: 1965-04-20
Filing date: 1965-04-20
Publication date: 1967-05-02
Anticipated expiration: 1984-05-02

Description

B. c. BLACK 3,317,233 SLING CONSTRUCTION AND METHOD OF MAKING SAME May 2, 1967 Filed April 20, 1965 INVENTOR. Born CI BLACK A TTOPNEY 3,317,233 SLING CONSTRUCTION AND METHOD OF MAKING SAME Boyd C. Black, Rte. 5, Newark, Ohio 43055 Filed Apr. 20, 1965, Ser. No. 449,453 8 Claims. (Cl. 234-74) This invention is related to a new wire rope sling and the method for making such sling and more particularly relates to a wire rope sling wherein a protective wearresistant traction and cushioning sheath is provided, permitting adaption of such rope structure to the lifting of machined parts as well as soft metal parts requiring special care in handling.

Wire rope slings usually are used for lifting and ban dlingof heavy apparatus and component parts ranging in the order of 15 pounds or more, and lend themselves especially to such handling because of their high tensile strengths, and correspondingly because of the wide range of loads which they can safely accommodate. Such rope slings are conventionally made of steel wire filaments grouped into strands twisted about a hemp core or wire to produce a composite having the strength of the steel wire, but having a give or yield imparted by the inclusion of the hemp core and the orientation of the Wire strands thereabout. Many specific instances arise in the handling of machined parts and soft metal parts where direct abrasive contact of metal of such a rope with metal of the object to be handled dictates that other means less abrasive to the object be used. Under such circumstances,

less abrasive hemp ropes are most frequently resorted to because of their softer, less damaging nature when made to conform to the object to be lifted, in comparison to theharder, non-smooth surfaced wire rope slings.

, Wire rope slings, however, are still much more desirable for the handling of such objects because of their greater tensile strength and longer life, as well as their less bulky and clumsy character in sizes of comparable strength.

. In view of theforegoing, it is an object of the present invention to provide an improved wire rope sling which incorporates the softer, non-abrasive characteristics of natural and synthetic fiber ropes without deterring from the inherent advantages of the wire rope, and additionally, providing other improvements in properties which heretofore have not been available in slings made either of wire -or fiber ropes, and in such sense, making the improved structure an all-purpose sling flexibly adaptable to an even wider range of uses than have been possible withboth wire and fiber rope slings taken as a group. It is another object of the present invention to provide an improved wire rope structure having greater conformability to objects carried, and while enabling such conformity, still having anon-abrasive character with practically no tendency toward marring of the objects, regardless ofthe greater intimacy of contact established therewith.

It is another object of the invention to provide a wire rope sling structure which has the effect of a greater yield with objects carried to establish an improved conformability, while yet actually not modifying the yield characteristic of the wire rope or cable itself.

It is still another objectof the invention to'provide awire sling structure wherein the splices for the loops formed therein are protected against damage from crushing and abrasion, thereby prolonging the effective life of the sling.

A sling meeting the above objectives canbe produced according to the present invention by combination of a grease and oil resistant tubular covering having a wearresistant exterior with a wire rope sling incorporating United States Patent 3,317,233 Patented May 2, 1967 a type wherein at least the interior which makes contact with the cable is both oil and grease resistant, as Well as adaptable to a sliding action over the surface of the strands of the rope, while the exterior is primarily tough and wear-resistant as well as of cushionable character, having a high coefiicient of friction, and yet being sufiiciently yieldable to provide a desired degree of conformability. A hose found successful in providing such characteristics is one available on the market having an interior of neoprene and an exterior of rubber preferably reinforced with cord for greater ruggedness and limited extensibility beyond its normal length. Although a hose made of the neoprene and rubber is found highly successful, hoses fully of neoprene or other synthetic resins or composites thereof for many specific applications will, also, be found desirable for such sling, structures. All neoprene hoses have the additional feature in that the exterior as well as the interior is oil and grease resistant,

which in many instances is highly desirable because of vention, beside its high strength, yielding, traction gripping, and non-abrasive action lies in the protection the covering oifer-s the wire rope itself, and in particular, the spliced zones of the sling which are otherwise most subject to damage in the rough handling of such slings.

Other objects and features which I believe to be characteristic of my invention are set forth with particularity in the appended claims. My invention, however, both in organization and manner of construction, together with further objects and advantages thereof may be best understood by reference to the following description taken in connection with the accompanying drawing in which:

FIGURE 1 is illustrative of the general manner in Which a sling constructed according to the present invention might be used to lift machined parts;

FIGURE 2 shows the sling construction of the present invention in its fully extended form;

g the sling casing;

FIGURE 4 is a cross-sectional view of the sling con 'struction of FIGURE 3 as taken on line 3-3;

FIGURE 5 illustrates an arrangement of equipment and tools for making a sling construction according to the principles of the present invention;

FIGURE 6 illustrates the arrangement of FIGURE 5 during the step of forming a concealed end loop in the sling construction.

Turning to the drawings in detail, FIGURE 1 shows a sling10 constructed according to the principles of the present invention supporting a metal hydro-propeller having machined surfaces and made of soft metal about which the sling must be wrapped to permit safe carriage thereof, such as by crane on the hook 12 of which the sling loops are held. In many instances, the sling is required to be wrapped about the machine parts to be lifted, as shown, by looping it in intimate contact with the machined surfaces of the parts. Under these circumstances, slippage of a conventional wire rope sling over the surfaces would likely damage the surfaces, and after many such instances would, also, wear the sling itself.

According to the present invention, however, a traction-covering material such as of a hose 30 is provided over the major length of the sling to offer a traction surface for materials lifted thereby, as well as to protect the wire rope and splices of the construction. The final construction of the sling is illustrated in FIGURE 2, showing the hose 30 extending over the full length of the wire rope between the end loops or

eyes

21 and 22.

FIGURES 3 and 4 illustrate more clearly actual construction details of the sling and show the hose construction and its manner of association with the wire rope in the zone of the splice forming the loop in one end of the sling. The hose 30 has an external layer 31 of rubber which extends for a substantial distance through the thickness thereof and is reinforced by material such as rayon or nylon cord 32, while the interior of the hose is lined with neoprene 33. The hose is selected with an interior diameter slightly larger than the diameter of the rope 20 so that a gap exists between the rope exterior and the hose interior to allow freedom of movement for the rope within the space provided.

The loop or eye 21 of the wire rope is formed by a splice 29 in a zone S where the end of the wire rope is, in a sense, folded back on itself to provide a loop of the size desired. The splice is an in-laid loop sometimes called a buried-end or Concealed-end splice. A loop splice of this type is used because of its adaptability to providing a taper from the base of the loop over a distance of the rope sufiicient to allow a wedging of the hose 30 over the splice. The ends of the strands of the rope in such a splice are laid inside of the rope in the splice zone and replace the core of the rope in this zone, thereby preventing cutting of the inside of the covering by providing ends. A well constructed splice of this type is practically impossible to break loose and no wrapping of seizings thereabout is necessary to maintain the splice, and especially is this so in the construction of the present invention since the hose covering offers protection for the splice. For example, when slings are used to handle bundles of steel products such as pipe, sheet, or strip stock, it is customary, after placing the bundle, to pull the slings out from under it. When the slings are made with ordinary spliced loops wrapped with seizing strand, it is only a short time before the serving is pulled off. The tucked ends of the strand are then exposed. These catch on the edges of the bundle and wires are turned up presenting a hazard to the workmen handling the slings. The hose covering, in the present instance, however, protects the splice against such occurrence and, also, provides a hand grip for workmen with a minimum of hazard to their becoming subjected to the abrasive and cutting action of strand ends.

Beside the hose interior diameter being selected for provision of a clearance space for the rope over the major length of the sling, it is, also, selected to permit wedging of the end of the hose on at least a portion of the spliced zone to prevent and end-to-end movement of the hose on the sling construction.

FIGURE 4 illustrates, respresentatively, the clearance between the outer surface of the rope 20 and the interior of the hose for the length of the sling outside of the spliced zones, while FIGURE 3 illustrates in cross-section the wedging of the splice in the end of the hose 30. With this arrangement, the hose is allowed to freely conform to the contours of the rope on being looped about objects to be lifted, while at the same time preventing unnecessary movement of the hose along the length of rope which would otherwise result in excessive abrading of the interior of the hose. The splice is tapered down from the base of the loop over the zone S down to the real diameter of the rope and is hammered out for smoothness so that there are no high spots in the splice.

FIGURES 5 and 6 illustrate the manner in which the new sling is made. Preliminary to the steps illustrated in these figures, however, an eye or loop 21 is first made in one end of a preselected length of wire rope 20. The loop is formed with a concealed-end loop splice as indicated above, which is hammered and smoothed out so that there are no high spots in the splice zone. The hose 30 is then cut to length so that in unstressed condition, it Will reach from the base of the loop 21 to the base of the loop to be formed. The cut length of hose is then slipped over the free end of the sling and moved to a position where it is wedged against the base of the loop 21. The end of the wire rope is then secured in a cable gripping tool 23 supported by rope falls or other pulling mechanisms suspended from a fixed position above. The free end of the hose on the unlooped end of the wire rope is then inserted in a vase 26 with the hose end abutting the under side of a pair of jaws 28 between which the wire rope 20 is passed up to the cable grip 23. The vise jaws 28 are maintained sufficiently far apart to allow free passage of the rope upward therebetween but sufiiciently close together so that upon the cable being drawn upward, the abutting end of the hose will not slip through the jaws. The rope falls 24 are then drawn up tightly, effecting a compressed distortion of the hose until a sufficient length of the rope 20 is provided above the end of the hose that a spliced loop of desired size can be formed above the hose end. When such a length is provided, the rope falls are securely locked so that no slippage will occur and a cable clamp 27 is then placed around the outside of the hose, just below the jaws of the vise, which clamp is then tightened until the hose end binds against the cable to prevent slippage of such end along the length of the rope when the rope falls are released.

The assembly is then removed from its position in the vise shown in FIGURE 5 and is suspended in an inverted position, as illustrated in FIGURE 6, whereupon a loop 22 is spliced into the free end of the rope.

Upon completion, the second concealed-end splice 22 is, also, hammered smooth and the cable clamp 27 is removed to allow the hose to extend itself to its normal dimension. Manual assistance is then exercised to wedge the end of the hose over the newly formed splice. In this respect, should difiiculty be experienced in drawing the end of the hose over the newly formed splice, it has been found that the mild application of heat to the end of the hose, either by use of hot water poured directly over the end, or by radiant heating of the end expands its diameter sufficiently to permit relatively easy slipping of the hose to its wedged position. An ordinary radiant electrical heater is very useful and successful in causing the necessary expansion of the hose end for wedging over the splice.

By way of example of an actual construction without intention that the invention be so limited, a successful sling which was subjected to conditions of actual use with extremely favorable results was constructed of a inch cable and a inch four-ply rubber rayon-reinforced air hose having a inch wall thickness and a neoprene inner liner. The cable was selected to be approximately ,5 inch smaller in diameter than the inside diameter of the hose covering it and further was selected to have a diameter such that a standard size hose could be used to thereby minimize the cost of materials. As indicated above, the neoprene liner of such a hose is more resistant than rubber to the grease and oil which is always present in the cable and, therefore, lengthens the life of the sling considerably.

While I have shown a certain particular form of my invention, it will be understood that I do not wish to be limited thereto, since many modifications may be made within the concepts of the invention. For example, the wire rope or cable as herein set forth can be a wire rope with a hemp core or one with a metal core. Correspondingly, either steel or iron rope may be used and a variety of concealed-end splices might be used to present the preferred tapered exterior for wedging of the hose ends. Any desired length of sling can be made, and correspondingly, the eyes of the sling can be of any dimension required for specific needs. Furthermore, ferrule or sleeve-type splice clamps secured to the rope, can be utilized in abutting relation with the hose construction to wedge and prevent sliding of the hose on the cable. In view of the foregoing, I therefore contemplate by the appended claims to cover all such modifications as fall within the true spirit and scope of my invention.

I claim as my invention:

1. A sling for lifting soft metal shaped articles and the like comprising a length of wire rope, a loop formed at each end of said sling by a splice of each end of said length back onto itself, each said splice being a concealed end splice gradually tapered down to the diameter of said rope over a portion of said rope extending from said loop, and a hose covering said sling over the full length of said sling between said loops including said splices.

2. A sling for lifting machine parts and the like comprising a length of wire rope, a loop formed at each end of said sling by a splice of each end of said rope back onto itself, each said splice being a concealed end splice tapered gradually downward to the diameter of said rope over a portion of said rope extending from said loop, and a hose covering the full length of the rope and splices between said loops, said hose having an inner diameter slightly larger than the diameter of said rope providing clearance space between said rope and hose interior for the length thereof between said splices.

3. A sling for lifting machine parts and the like comprising a length of wire rope, a loop formed at each end of said sling by a splice of each end of said rope back onto itself, each said splice being a concealed end splice tapered gradually downward to the diameter of said rope over a portion of said rope extending from said loop, and a hose covering the full length of the rope and splices between said loops, said hose having an interior lining of oil resistant, yieldable and stretchable material.

4. A sling for lifting machine parts and the like comprising a length of wire rope, a loop formed at each end of said sling by a splice of each end of said rope back onto itself, each said splice being a concealed end splice tapered gradually downward to the diameter of said rope over a portion of said rope extending from said loop, and a hose covering the full length of the rope and splices between said loops, said hose having an interior lining of neoprene.

5. A sling for lifting machine parts and the like comprising a length of wire rope, a loop formed at each end of said sling by a splice of each end of said rope back onto itself, each said splice being a concealed end splice tapered gradually downward to the diameter of said rope over a portion of said rope extending from said loop, and a hose covering the full length of the rope and splices between said loops, said hose having an inner diameter slightly larger than the diameter of said rope providing clearance space between said rope and said hose interior between said loops, said splices for at least a portion of their length immediately adjacent said loop having a diameter dimension slightly greater than the interior of said hose to wedge said hose between splices and thereby prevent end to end movement of said hose on said sling.

6. A sling for lifting machine parts and the like comprising a length of wire rope, a loop formed at each end of said sling by a splice of each end of said rope back onto itself, each said splice being a concealed end splice tapered gradually downward to the diameter of said rope over a portion of said rope extending from said loop, and a hose covering the full length of the rope and splices between said loops, said hose having an interior lining of neoprene and an exterior casing of rubber, said hose having an inner diameter slightly larger than the diameter of said rope providing a clearance between said rope and said hose interior between said loops, said loops for at least a portion of their length immediately adjacent said loop having a diameter dimension slightly greater than the interior of said hose to wedge said hose between splices and thereby prevent end to end movement of said hose on said sling.

7. The method of making a composite sling structure of wire rope and a hose covering having an inner diameter slightly larger than said rope comprising in sequence splicing a loop in one end of a length of wire rope, passing the opposite end of said rope through said hose to a position of projection from said hose, compressing said hose along its length to a distorted contracted condition suflicient to permit splicing of a loop in the other end of said rope, clamping said hose in tight surrounding relation against said rope, splicing a loop in said other end of the rope, and releasing the hose from its contracted condition and extending it over the full length of said rope including the splices for said loops.

8. The method of claim 7 wherein the released hose is heated to facilitate its being forcefully extended over the full length of said sling and both of said splices.

References Cited by the Examiner UNITED STATES PATENTS 2,454,417 11/1948 Zerr 57142 2,491,256 12/1949 Engelke 5723 2,558,553 6/1951 Hansen et al. 57-159 X 2,602,233 7/1952 Irving 57-153 3,018,319 1/1962 Quayle.

3,067,570 12/1962 Nischan 57-159 X M. HENSON WOOD, JR., Primary Examiner. I. N. ERLICH, Assistant Examiner.