US3868137A

US3868137A - Cargo sling and feed-through link therefor

Info

Publication number: US3868137A
Application number: US394182A
Authority: US
Inventors: John William Friend
Original assignee: Individual
Current assignee: Individual
Priority date: 1973-09-04
Filing date: 1973-09-04
Publication date: 1975-02-25
Anticipated expiration: 1992-02-25

Abstract

A cargo sling is provided having novel, generally rectangularshaped identical links secured to opposite ends of an elongated load-carrying web or band. The links of the sling are of a size and shape so that either link can be passed through the opening in the other link in wrapping the web portion of the sling about a load to be hoisted, and this passed-through link can be then secured to a hoisting hook for lifting the load. Preferably, the top cross member of the link is formed to have an outward curvature so that the link is free to shift somewhat after being placed on a hoisting hook, thereby permitting the link to find its own deadweight center with respect to the hook and the load being lifted. Although the links of the invention can be used with any type of load-carring web or band, they are utilized, in a preferred embodiment, with a woven, steel cable web.

Description

United States Patent [111 3,868,137 [4 1 Feb.25, 1975 CARGO SLING AND FEED-THROUGH LINK THEREFOR John William Friend, 3000 Nassau Dr., Vero Beach, Fla. 32960 Filed: Sept. 4, 1973 Appl. No.: 394,182

Inventor:

US. Cl. 294/74 Int. Cl. B66c l/18 Field of Search 294/67 EA, 74, 75,77, 294/78 R; 24/115 K, 122.6, 230.5 BA, 230.5 CS, 265 R, 265 CC, 265 EC, 265 H, 265 AL, 200

References Cited UNITED STATES PATENTS 10/1951 Andersen 294/74 10/1964 Glover 294/74 X 8/1965 Elsner 24/265 AL 3,352,590 ll/l967 Barthule 294/74 3,583,750 6/1971 Norton 294/74 FOREIGN PATENTS OR APPLICATIONS 786,974 11/1957 Great Britain 294/74 at. iiiiiii will 1 Primary Examiner-Richard A. Schacher Assistant ExaminerJohnny D. Cherry Attorney, Agent, or Firm-Howard E. Thompson,

[57] ABSTRACT A cargo sling is provided having novel, generally rectangular-shaped identical links secured to opposite ends of an elongated load-carrying web or band. The links of the sling are of a size and shape so that either link can be passed through the opening in the other link in wrapping the web portion of the sling about a load to be hoisted, and this passed-through link can be then secured to a hoisting hook for lifting the load. Preferably, the top cross member of the link is formed to have an outward curvature so that the link is free to shift somewhat after being placed on a hoisting hook,

thereby permitting the link to find its own deadweight' center with respect to the hook and the load being lifted.

Although the links of the invention can be used with any type of load-carting web or band, they are utilized, in a preferred embodiment, with a woven, steel cable web.

17 Claims, 4 Drawing Figures CARGO SLING AND FEED-THROUGH LINK THEREFOR This invention relates to novel links for use with cargo slings, the links being formed from identical, rectangularly-shaped link members joined to each other by a load-carrying web portion and are of a size and shape that permits either link and a portion of its attached web to be passed through the opening of the other link after the web portion has been secured about a load, the first link then being secured to a hoisting hook for lifting the load. I

BACKGROUND OF THE INVENTION The use of cargo slings for lifting heavy loads is generally well-known and such slings are in wide use in the construction industry as well as in ship loading and unloading and allied activities. Typically, these cargo slings comprise a load bearing or carrying portion, such as a web, band, or strap, having means for securing the web portion about the load to be lifted and means at least at one end thereof for securing the web to a hoisting hook. A variety of materials have been commonly used in forming the web portions, such as wire, rope, cables and the like, which are braided or provided in mesh form to impart load lifting strength to the web, as well as fabric webs woven from natural fibers as well as synthetic materials such as Nylon, Dacron and the like. If of woven fabric construction, these webs are oftentimes reinforced by interweaving therein a plurality of wire or metal strands.

The hardware at the ends of cargo slings, generally referred to as links, may be provided in a variety of shapes, such as triangular, U-shaped D-rings, and the like. Such links are generally secured to the web portion by passing a web end through a member of the link, folding it back on the main portion of the web, and bonding it thereto by stitching, metal clamps, and the like.

Examples of such prior art cargo slings are disclosed and described in recent United States Patents, such as US. Pat. Nos. 3,625,559 to Lawrence; 3,583,750 to Norton; 3,456,976 to Hausmann; and 3,203,067 to Elsner.

Generally, these prior art cargo slings are difficult to work with, have narrowly limiting load capacities which require frequent changing of different slings, are not very durable, and are further limited in that they can be secured to a load only in one manner. Most slings are of a type requiring both end links to be engaged by a hoisting hook. In those cargo slings where the webs are intended to be looped around a load with only one link engaging a hoisting hook, it has been customary to employ a different type link or an adaptor to receive the web portion of the sling.

THE INVENTION It has now been found that by utilizing identical, rectangular-shaped links at each end of a web member a cargo sling is formed which is strong and durable, and

yet flexible and easy to use by virtue of the size and member being such that the thickness of this member increases gradually from itsends toward its center. The size and shape of the links is such that, whenone link is oriented so that its width lies substantially in the same plane as the diagonal of the other link, the first link and a portion of the web secured thereto can be passed through the second link after the web has been secured about a load, and the first link then placed on a hoisting hook. By virtue of the curvature of the top member of the link, it is free to shift after being placed upon a hook, thereby permitting the link to find its owndead weight center with respect to the hook and the load to be lifted. This minimizes wear on the link and thereby prolongs its life. Since the links are of the same size, ei-

ther link can be secured to a hoisting hook, thus further prolonging the useful life of the links, and equally important, distributing the wear of the web portion of the sling. Furthermore, the size and shape'of the links permit them to be used with a wide range of hook sizes with minimum head room and without using costly and clumsy adaptors.

Although any type and kind of web may be utilized with the links of the invention, in a preferred embodiment, the web is formed from a single continuous cable length or strand which is spirally looped about each of the carrying members of spaced apart links, until each of these carrying members contains a plurality of looped strands in closely spaced relation to each other. A second, continuous length of cable is then disposed transverse to the first cable along itsentire length and interwoven therewith in a manner similar to that used in forming basket hitches. When the second cable is thus interwoven only once along the length of the longitudinal, spirally looped cable, then a single woven web is formed. However, the same or a second cable can be further interwoven in the same manner but in the opposite directionto provide a web of double woven structure. In either embodiment, the web portion has substantially flat surfaces, exhibits minimal internal stresses and wear, and yet any desired or required length, remains flexible, durable and is of greater strength than those hereto utilized.

The novel features of the cargo sling and improved links of the invention will be more fully appreciated from a consideration of the following description, together with the accompanying drawing in which the structural details are identified by suitable reference characters in each of the views and, in which:

FIG. 1 is a fragmentary view of a cargo sling embodying improved links of the present invention and illustrating one link secured to a hoisting hook after said one link and a portion of the web secured thereto has been passed through the other link in forming a load carrying loop.

FIG. 2 is an enlarged and longitudinally shortened view of a cargo sling illustrating one form of web structure in association with the improved links.

FIG. 3 is a view taken substantially on the broken line 3-3 of FIG. 2; and,

FIG. 4 is a sectional view of the link structure taken on the line 4-4 of FIG. 2.

As shown most clearly in FIGS. 1 and 2, the cargo sling of the invention comprises a web member, generally identified by reference numeral 10, the ends of which are secured to the web-carrying members of identical links 11 and 11a. In FIG. 1, it can be seen that link 11 and a portion of web 10 has been passed through the opening of link 11a and placed upon a hoisting hook 12 with the main portion a of the web providing a load carrying loop. 7

The structural details of links 11, 11a are illustrated in FIGS. 2 and 3 and, as can be seen, links 11, 11a are each of unitary, generally rectangular-shaped structure having

parallel sides

13, 14 and 13a, 14a, a

bottom cross member

15 and 15a which is the carrying member to which web 10 is secured, and an outwardly curved top cross member 16 and 16a. Although the links can be manufactured in various sizes, the overall length of the links is preferably about 50 percent greater than their overall width, and the rectangular opening formed by the link members is preferably of about the same proportion.

Parallel sides 13, 1 4 and 13a, 14a are of uniform cross-section and are preferably substantially square having flat faces and rounded edges, as seen inFIG. 4.-

The

bottom members

15 and 15a, which are perpendicularly disposed between the side members are formed to have rounded upper faces 17, 17a and

sides

18, 19 and 18a, 19a which taper toward rounded, slightly outwardly curved

outer faces

20 and 20a (FIG. 3 and 4), r.

the radius of curvature of outer faces being slightly greater than the overall length of the link, and preferably about one-third greater.

The cross-sectional configuration of the top members 16 and 16a is generally the same as that of the bottom members having rounded inner surfaces 21, 21a and

sides

22, 23 and 22a, 23a which taper toward rounded

outer surfaces

24 and 24a. As mentioned earlier, the top member of the links is curved outwardly, the radius of curvature of inner and outer surfaces of this member being the same, preferably about one-half the overall length of the link, so that the cross-sectional thickness of the top member increases gradually from its ends to-. ward its center.

The rounded portions of the members comprising the links impart added safety and comfort factors to their use and to the persons handling them. Furthermore, by

they can be used indiscriminately with great flexibility and ease. Since either link can be placed upon a hoisting hook, regardless of the size or shape of the hooks, no adaptors are needed for different hook sizes, and placement on a hook can be accomplished with a minimum of head room clearance. This is illustrated in FIG. 2 where hook 12, shown in full line, is of one size and After a load has been placed upon the web portion 10,

or the web portion 10 has been slipped beneath a load and wrapped about it, one link, such as 11 (FIG. 1), can be oriented so that its width lies substantially inthe same plane as the diagonal of the. outer link 11a, thereby permitting the firstlink II and a portion of the web 10 secured to it to be passed through the opening in the second link 11a and placed .on a hoisting hook 12. In so threading one link through another, a loop 10a is formed inthe body of the web 10 about a load and this loop 10a tends to. tighten about andfirmly secure a load as the load is lifted. Since either link can be placed'upon a hook,.different parts of the web portion will-come into contact with a load minimizing the number of stress points of the web which receive excessive woven fabric, woven metalor other construction,'en-

hanced strength and durability in' use is achieved when the web portion comprises a multi-stranded wire rope or cable construction in which the multiplicity of strands are flexed andtransversely interlaced at longitudinally spaced intervals with spacer strands which,

provide what might be referred to as a basket weave pattern longitudinally of the web, as clearly illustrated rally passed around mounted ends 15, 15a of links spaced apart toprovide the desired web length, this spiral wrapping being continueduntil the transverse dimensions of the mounting ends 15, 150 are substan-. tially occupied by closely spaced loops 25a, as seen in FIG. 2 of the drawing. The final spiral wrapping of the cable 25 should terminate at the link end 15 to which the cable 25 was originally attached and can be an providing indentical links at eachendsof the web 10,

chored by means of a second crimp or clamp device 26 t FIGS. 2 and3 of the drawing, this disposes and equal;

' number of cable. strands 25cand'25d at opposed sides mounting end 15a. If desired, the spacer strand 28, can

of the link mounting. ends 15,1511.

The spaced links 11, 11a are then placed underslight tension to equalize the tension in cable 25 throughout 7 the multiple spiral wraps thereof, and starting adjacent one of the link mounting ends 15 the groups of

strands

25c, 25d are flexed to reverse their positions with respect to the longitudinal centerline of the assemblage providing a transverse opening 27 through which a spacer strand 28 is transversely passed. The groups of

strands

25c, 25d are then again flexed to their original orientation with respect to the longitudinal center line of the assemblage forming an adjacent; passage 27a 7 7 continued until the entire distance betweenthe link.

mounting ends 15,-l5a.has been thus interlaced with the spacer strand 28, with the final transverse pass of the spacer 28 being closely adjacent the opposed link terminate atthis point providing .whatmight be termed a single basketweave construction.

The actual showing in the drawing indicates the strand28. as being continued as 2.80 passing in the reverse direction through the

transverse passages

27, 27a to provide what might be termed a double basket weave construction. Ends of the

spacer strand

28, 28a

can terminate in the transverse passage 27 adjacent link mounting end but as shown in the drawing these ends are preferably anchored by lacing through the looped strands adjacent link mounting end 15,

as shown at 28c, and returning the ends again to passage 27, as shown at 28d. This anchorage of the spacer strand 28 makes for a very durable construction eliminating exposed cable ends. The single or double basket weave interlacing of the spacer strand 28 provide several useful functions in the improved web structure. Primarily, it imparts to the web an orderly and generally flat configuration which permits handling in the same manner as conventional woven fabric or woven metal webs. The interwoven construction and the yieldable compressibility of the

strand groups

250 and 25d against the

spacer strands

28, 28a provide for unique equalizing of tensions within the cable windings 25 in adapting the weave to various load conditions, particularly as the web is passed through one of the links 11, 11a in the manner previously described. In fact, the basket weave construction is considered as providing what might be termed a built-in shock absorbing feature, in that the transverse compressibility around the spacer strand 28 can permit localized extension, or give, in the individual lengths of the strand 25.

The

spacer strands

28, 28a can be formed from various materials, such as multi-stranded plastic or metal cables or plastic covered metal cables. In practice, however, excellent results are obtained when using a bare multi-stranded metal cable for the spacer 28, particularly in conjunction with a plastic coated cable 25, as this provides something of a gripping or positioning action, while at the same time permitting limited relative movement between the

strand

28, 28a and the interwoven

portions

25c, 25d of the cable 25.

Various changes and modifications in the cargo sling and end links herein disclosed may occur to those skilled in the art,'and to the extend that such changes and modifications are embraced by the appended claims, it is to be understood that they constitute part of the invention.

What is claimed is:

l. A link for cargo slings comprising a unitary, generally rectangular-shaped member having parallel sides of uniform cross-section; a bottom cross member to which a cargo sling is secured, said bottom member being perpendicularly disposed between said parallel sides and having a rounded upper face tapering toward a rounded, slightly outwardly curved lower face and providing a generally triangular cross-section for said bottom member in a direction longitudinally of said link; and, an outwardly curved top cross member having a rounded inner surface tapering toward a rounded outer surface and providing a generally triangular cross-section for said top cross member in a direction longitudinally of said link, the overall length and overall width of saicllink being such that a first link can be passed through a second, identical link when said first link is oriented so that its width is substantially in the same plane as the diagonal of said second link.

2. The link of claim 1, wherein the overall length of said link is about 50 percent greater than its overall width.

3. The link of claim 1, wherein said parallel sides are substantially square and have flat surfaces and rounded edges.

4. The link of claim 1, wherein the radius of the arc of the curvature of the lower face of said bottom member is slightly greater than the overall length of said link.

5. The link of claim 4, wherein said radius is about one-third greater than the overall length of said link.

6. The link of claim 1, wherein the rounded inner and outer surfaces of said top cross member have the same radius of curvature such that the cross-sectional thick ness of said top member gradually increases from its ends toward its center.

7. The link of claim 6, wherein said radius of curvature is about one-half the overall length of said link.

8. A cargo sling comprising two links as defined in claim 1 having the bottom members thereof joined together by an elongated flexible web having a width no greater than the width of said links, and a length to provide a practical load engaging loop when one link and a portion of said web is passed through the other link in the load hoisting orientation of said sling.

9. A cargo sling as defined in claim 8, wherein the web comprises a flexible cable strand secured to one of said links and spirally wound between the two links to provide a plurality of connecting strands which normally would form separate groups forwardly and rearwardly of the aligned and tensioned links, the forward and rearward orientation of said groups of strands being reversed a plurality of times longitudinally of said web by other cable means passing transversely between said groups of strands in zigzag fashion throughout the length of said web.

10. A cargo sling as defined in claim 9, wherein said other cable means makes one zigzag pass throughout the length of said web providing a single basket weave effect. I

11. A cargo sling as defined in claim 9, wherein said other cable means makes two zigzag passes throughout the length of said web providing a double basket weave effect.

12. A cargo sling as defined in claim 9, wherein the first named cable strand comprises a high tensile strength metal cable with a plastic coating.

13. A cargo sling as defined in claim, 9, wherein the first named cable strand comprises a high tensile strength metal cable with a plastic coating, and said other cable means comprises a braided cable having surface irregularities adapted to provide non-slip engagement with the plastic coating of said first cable strand.

14. A cargo sling as defined in claim 13, wherein said second cable means comprises a braided metal cable.

15. A link for cargo slings comprising a unitary, generally rectangular-shaped member having parallel sides of uniform, substantially square cross-section, flat surfaces and rounded edges; a bottom cross member to which a cargo sling is secured, said bottom member being perpendicularly disposed between said parallel sides and having a rounded upper face tapering toward a rounded, slightly outwardly curved lower face and providing a generally triangular cross-section for said bottom member in a direction longitudinally of said link, the radius of curvature of said lower face being slightly greater than the overall length of said link; and, an outwardly curved top cross member having a rounded inner surface tapering toward a roundedouter surface and providing a generally triangular crosssection for said top cross member in a direction longitudinally of said link, the radiusof curvature of the arcs of said inner and outer surfaces being the same and about one-half the overalllength of said link such that the cross-sectional thickness of said top member gradually increases from its ends to its center, the overall length and the overall width of said link being such that a first link can be passed through the rectangular opening of a second; identical link when said first link is oriented so that its width islsubstantially in the same plane t

Claims

1. A link for cargo slings comprising a unitary, generally rectangular-shaped member having parallel sides of uniform crosssection; a bottom cross member to which a cargo sling is secured, said bottom member being perpendicularly disposed between said parallel sides and having a rounded upper face tapering toward a rounded, slightly outwardly curved lower face and providing a generally triangular cross-section for said bottom member in a direction longitudinally of said link; and, an outwardly curved top cross member having a rounded inner surface tapering toward a rounded outer surface and providing a generally triangular crosssection for said top cross member in a direction longitudinally of said link, the overall length and overall width of said link being such that a first link can be passed through a second, identical link when said first link is oriented so that its width is substantially in the same plane as the diagonal of said second link.

6. The link of claim 1, wherein the rounded inner and outer surfaces of said top cross member have the same radius of curvature such that the cross-sectional thickness of said top member gradually increases from its ends toward its center.

10. A cargo sling as defined in claim 9, wherein said other cable means makes one zigzag pass throughout the length of said web providing a single ''''basket weave'''' effect.

11. A cargo sling as defined in claim 9, wherein said other cable means makes two zigzag passes throughout the length of said web providing a double ''''basket weave'''' effect.

13. A cargo sling as defined in claim 9, wherein the first named cable strand comprises a high tensile strength metal cable with a plastic coating, and said other cable means comprises a braided cable having surface irregularities adapted to provide non-slip engagement with the plastic coating of said first cable strand.

15. A link for cargo slings comprising a unitary, generally rectangular-shaped member having parallel sides of uniform, substantially square cross-section, flat surfaces and rounded edges; a bottom cross member to which a cargo sling is secured, said bottom member being perpendicularly disposed between said parallel sides and having a rounded upper face tapering toward a rounded, slightly outwardly curved lower face and providing a generally triangular cross-section for said bottom member in a direction longitudinally of said link, the radius of curvature of said lower face being slightly greater than the overall length of said link; and, an outwardly curved top cross member having a rounded inner surface tapering toward a rounded outer surface and providing a generally triangular cross-section for said top cross member in a direction longitudinally of said link, the radius of curvature of the arcs of said inner and outer surfaces being the same and about one-half the overall length of said link such that the cross-sectional thickness of said top member gradually increases from its ends to its center, the overall length and the overall width of said link being such that a first link can be passed through the rectangular opening of a second, identical link when said first link is oriented so that its width is substantially in the same plane as the diagonal of said second link.

16. The link of claim 15, wherein the radius of curvature of the lower face of said bottom member is about one-third greater than the overall length of said link.

17. The link of claim 15, wherein the overall length of said link is about 50 percent greater than its overall width.