US3743342A

US3743342A - Lifting clamp

Info

Publication number: US3743342A
Application number: US00186627A
Authority: US
Inventors: N Kell
Original assignee: Motors Liquidation Co
Current assignee: Motors Liquidation Co
Priority date: 1971-10-05
Filing date: 1971-10-05
Publication date: 1973-07-03
Anticipated expiration: 1990-07-03

Abstract

In a preferred form, this disclosure relates to a releasable lifting clamp which comprises a hollow cylindrical body portion with a plurality of axially elongated, circumferentially spaced slots therein which terminate at one end in inclined surfaces. The clamp also includes a hollow cylindrical locking sleeve which is supported upon the body in a concentric manner for sliding movement thereon in opposite directions and which has a plurality of circumferentially spaced slots therein. A plurality of jaws which have tangs received within the slots of the locking sleeve are slidably received within the slots of the body portion for movement with the locking sleeve. The lifting clamp further includes a spring means which biases the jaws into engagement with the inclined surfaces. The locking sleeve when moved in first and second directions upon the body and against the bias of the spring means and with the bias of the spring means serves to expand and contract the jaws, respectively.

Description

United States Patent [1 1 Kell i 1 LIFTING CLAMP [75] Inventor: Nathaniel B. Kell, Indianapolis,

Ind.

[73] Assignee: General Motors Corporation,

Detroit, Mich.

[22] Filed: Oct. 5, 1971 [2]] Appl. No.: 186,627

.[52] US. Cl. 294/8631, 294/8633 [51] Int. Cl B25b 5/08 [58] Field of Search 294/115, 86.27, 86.28,

294/8629, 86.16, 86.17, 86.18, 86.19, 86 R, 83 R, 99 S, 100, 86.30, 86.31, 86.26, 86.33,

Primary Examiner-Harvey G. Hornsby Assistant Examiner-James W. Miller A ttorney- W. E. Finken and W. A. Schuetz July 3,1973

[57] ABSTRACT In a preferred form, this disclosure relates to a releasable lifting clamp which comprises a hollow cylindrical body portion with a plurality of axially elongated, circumferentially spaced slots therein which terminate at one end in inclined surfaces. The clamp also includes a hollow cylindrical locking sleeve which is supported upon the body in a concentric manner for sliding movement thereon in opposite directions and which has a plurality of circumferentially spaced slots therein. A plurality of jaws which have tangs received within the slots of the locking sleeve are slidably received within the slots of the body portion for movement with the locking sleeve. The lifting clamp further includes a spring means which biases the jaws into engagement with the inclined surfaces. The locking sleeve when moved in first and second directions upon the body and against the bias of the spring means and with the bias of the spring means serves to expand and contract the jaws, respectively.

3 Claims, 4 Drawing Figures PATENTEDJUL3 ma 7 3753342 ATT R/VEY LIFTING CLAMP The present invention relates to a lifting clamp, and more particularly to a releasable lifting clamp having jaws which can be expanded and contracted to grasp and release other objects.

Clamps have heretofore been provided which include a plurality of jaws which have certain portions cammed to expand or contract the jaws to grasp and release other objects. For telecentric see U.S. Pat. No. 1,583,767. Lifting clamps have also been previously provided wherein the contraction of the jaws occurs as a result of the sliding axial movement of a locking sleeve upon a body portion within which the jaws are mounted. For example, see U.S. Pat. No. 1,570,065. The aforementioned clamps are of a complex construction and have the disadvantage that assembly and disassembly is difficult when it is necessary to replace broken members, because mechanical fasteners, welding, staking, etc. are usually required for assembly.

Accordingly, an important object of the present invention is to provide a new and improved releasable clamp which is of a simple and economical construction, wherein mechanical fasteners, etc are not required for assembly and wherein any component of the lifting clamp can be easily removed and replaced.

Another object of the present invention is to provide a new and improved releasable lifting clamp comprising a hollow cylindrical body which has a plurality of elongated, axially extending, and circumferentially spaced slots therein which terminate at one end in inclined cam surfaces, a hollow cylindrical locking sleeve which is supported upon the body in a concentric manner for sliding movement thereon in opposite directions and which has a plurality of circumferentially spaced slots therein, a plurality of jaws having tangs received within the slots of the locking sleeve and which are slidably received within the slots of the body portion for movement with the locking sleeve, and a spring means which biases the jaws radially outwardly into engagement with the cam surfaces, and said locking sleeve when moved in first and second opposite directions against the bias and with the bias of the spring means serving to expand and contract the jaws, respectively.

These and other objects of the invention are accomplished, in a preferred embodiment, by providing a lifting clamp which comprises a hollow cylindrical body having a plurality of axially extending and circumferentially spaced slots therein which terminate at a position adjacent one end of the body in inclined surfaces. The body has a radially outwardly extending'lip adjacent the one end of the body and also has means attached to its other end for attaching the lifting clamp to a lifting device. The lifting clamp also includes a hollow cylindrical locking sleeve which has one end engaging the lip of the body and which is supported thereby in a con centric manner for sliding movement upon the body between a forward and a retracted position. The locking sleeve also has a plurality of circumferentially spaced slots therein. The lifting clamp further includes a plurality ofjaws which have tangs at their upper ends that are received within the slots of the locking sleeve and which have their lower ends formed in a hooked manner. The jaws are slidably received within the slots of the body for movement relative to the body with the locking sleeve. Further, the lifting clamp includes a compression spring within the body which engages the upper ends of the jaws to bias the jaws radially outwardly to maintain the hooked ends of the jaws in engagement with the inclined surfaces during movement of the locking sleeve and jaws relative to the body and the compression spring biasing the locking sleeve toward its forward position whereby the movement of the locking sleeve toward its retracted position in opposition to the bias of the spring and toward its forward position with the bias of the spring effects expansion and contraction, respectively, of the jaws. I

These and other objects of the invention will become more fully apparent from the following description and drawings wherein:

FIG. 1 is an axial cross-sectional view with portions shown in elevation of the lifting clamp of the present invention;

FIG. 2 is a cross-sectional view taken along lines 2-2 of FIG. 1;

FIG. 3 is a view similar to FIG. 1 showing different parts of the lifting clamp of the present invention in different positions; and

FIG. 4 is a perspective of a part of the lifting clamp of the present invention. I

As representing a preferred embodiment of the present invention, the drawings show a lifting clamp 10 which broadly comprises a hollow cylindrical body portion 12, a hollow cylindrical locking sleeve 14 which is supported upon the body portion 12 in a concentric manner, a plurality of jaws l6, and a spring means 18 which serves to bias the jaws 16 in one direction.

Referring to FIGS. 1 and 2, the body portion 12 of the lifting clamp 10 includes a hollow cylindrical portion 20 and an upper end portion 22. The hollow cylindrical portion 20 has an inner periphery 24 which with the lower surface 26 of the upper end portion 22 defines a cylindrical inner chamber 28 therebetween which has an open end 30 at the lower most portion of the hollow cylindrical portion 20. The hollow cylindrical portion 20 includes three axially extending and generally rectangularly shaped through slots 31 therein which are circumferentially spaced approximately apart. As previously stated, the slots 31 extend axially, as shown in FIG. 1, and terminate at their lower end in surfaces 34 which are progressively tapered radially inwardly from the outer periphery 35 and which terminate at the inner periphery at a position immediately adjacent the open end 30 of the inner chamber 28. The cylindrical portion 20 also includes a radially outwardly extending lip or flange 36 which projects therefrom at a position immediately adjacent the open end 30 of the inner chamber 28. The upper end portion 22 has a threaded axially extending aperture 38 which receives a complementary threaded eyelet member 40 in order that the lifting clamp 10 can be attached to a suitable lifting device (not shown), such as a hydraulic hoist.

The locking sleeve 14 is hollow, cylindrical, and shaped complementary to the outer periphery 35 of the cylindrical portion 20 of the body 12 and is slidably received thereon. The locking sleeve .14 is normally in a forward position in which its lower end 42 engages the radial lip 36 of axis, body portion 12 and is in this manner supported upon the body 12. The locking sleeve 14 also includes three radially extending slots or openings 44 therethrough which are circumferentially spaced approximately 120 apart. It should be noted that the locking sleeve 14 is normally supported in a concentric manner upon the cylindrical portion 20 of the body 12 and is slidable thereon between a forward position, as

shown in FIG. 1, and a retracted position, as shown in FIG. 3.

Referring to FIGS. 1 and 4, the lifting clamp also includes three jaws 16 which are generally elongated members having a rounded lower end .46 with a projection or projecting portion 48 extending perpendicularly therefrom to form a hooked end 50 for the purpose of grasping other objects. The jaws 16 have an upper end 52 with tangs or projecting portions 54 projecting perpendicularly therefrom and oppositely the projections 48.'Further, the upper end 52 of each jaw 16 has a laterally extending notch 56 opposite each tang 54 which defines a shoulder or seat 57. Each jaw 16 is slidably received within the slots 31 of the body portion 12 and has its tang 54 received within one of the slots 44 in the locking sleeve 14. The axial'length of the slots 31 is greater than the length of the jaws.

The spring means 18 can be any suitable type of spring and is herein shown as a coiled compression spring 18 which is positioned within the inner chamber 28 of the body 12. The spring 18 is shown as having one end in abutting engagement with the first surface 26 of the upper end portion22 of the body 12 and having its other end in abutting engagement with the shoulder 57 of the jaws 16. In this manner, the spring 18 maintains the tangs S4 of the jaws 16 within the holes 44 of the locking sleeve 14 and biases the sleeve toward its forward position and the rounded lower ends 46 of the jaws 16 into engagement with tapered surfaces 34 of the body portion 12.

When it is desired to grasp an object 60, the locking sleeve 14 is then manually moved upwardly to its retracted position, as shown in FIG. 3, and the clamp is placed over an object 60 to be lifted. Because the jaws 16 have their tangs 54 received within the holes 44 of the locking sleeve 14, the jaws 16 are caused to move upwardly with the sleeve and within the slots 31 of the body 12. As the locking sleeve 14 is moved upwardly against the bias of the spring 18, the spring 18 maintains the rounded end portion 46 of the jaws 16 in engagement with the tapered surfaces 34 of the body portion 12. This results in the hooked ends 50 of the jaws 16 being pivoted'radially outwardly into the slots 31 in the body portion 12 and to expand their relationship between one another. When the opening between the hooked ends 50 of the jaws 16 is greater than the size of the object to be grasped 60, the lifting clamp 10 is moved downwardly with the object 60 being received within the open end 30 of the inner chamber 28.

Thereafter, the locking sleeve 14 is released and is moved downwardly with respect to the body portion 12, as shown in FIGS. 1 and 2, by the spring means 18. The downward movement of locking sleeve 14 moves the jaws l6 downwardly within the slots 31 and the tapered surfaces 34 of the body portion 12 cause the hooked ends 50 of the jaws 16 to be moved radially inwardly by virtue of the engagement therebetween which is maintained by the compression spring 18. The radially inward movement of the hooked ends 50 of the jaws 16 enables the jaws 16 to grasp the object 60 and, thereafter, the object 60 can be lifted by operation of the lifting device (not shown).

The foregoing disclosure relates to only one embodiment of the invention which may be modified within the scope of the appended claims.

What is claimed is:

1. A releasable clamp, comprising: a hollow cylindrical body portion having a plurality of elongated .cir-

cumferentially spaced slots therein, said slots terminat- 7 ing at one end in inclined surfaces; a hollow cylindrical locking sleeve being supported upon said body in a concentric manner for sliding movement thereon in opposite directions and having a plurality of circumferentially spaced slots therein; a plurality of jaws having tangs received within said slots of said locking sleeve and being slidably received within said slots of said body portion whereby said jaws are movable with said locking sleeve; spring means for biasing said jaws radially outwardly into engagement with said inclined surfaces; said locking sleeve when respectively moved in opposite directions against the bias and with the bias of said spring means serving to expand and contract said jaws, respectively.

2. A lifting clamp, comprising: a hollow cylindrical body portion having a plurality of elongated circumferentially spaced slots therein, said slots terminating at one end in inclined surfaces; a cylindrical outer-locking sleeve being supported upon and about said body in a concentric manner for sliding movement thereon between forward and retracted positions; a plurality of jaws pivotally supported upon'said locking sleeve and being slidably received within said slots of said body portion whereby said jaws are moveable with said locking sleeve; and spring means for engagingly biasing said jaws radially outwardly into engagement with said inclined surfaces; said locking sleeve when moved toward its retracted position against the bias of said spring means serving to expand said jaws and the bias of said spring means moving said locking sleeve when released toward its forward position in which said inclined surfaces engage and contract said jaws.

3. A lifting clamp, comprising: a hollow cylindrical body portion having a plurality of axially extending and circumferentially spaced slots therein, said slots terminating at a position adjacent one end of said body portion in inclined surfaces, said body portion having a radially outwardly extending lip adjacent said one end of said body, said body having means for attaching said lifting clamp to a lifting device; a hollow cylindrical locking sleeve having one end engaging said lip of said body and being supported thereby in a concentric manner upon said body for sliding movement thereon between forward and retracted positions, said locking sleeve having a plurality of circumferentially spaced slots therein; a plurality of jaws slidably received within said slots of said body for movement relative to said body with said locking sleeve, said jaws having a tang and a notch at their upper ends, said jaws having their lower ends formed in a hooked manner; a compression spring within said body having one end engaged within said notches of said jaws for biasing said jaws radially outwardly to maintain said hooked ends in engagement with said inclined surfaces during movement of said locking sleeve and jaws relative to said body and'for maintaining said tangs of said jaws within said holes of said locking sleeve and said compression spring for biasing said locking sleeve towardv its forward position whereby movement of said locking sleeve to its retracted position in opposition to the bias of said spring and to its forward position with the bias of said spring effects expansion and contraction, respectively, of said hooked ends of said jaws.

i l I!

Claims

1. A releasable clamp, comprising: a hollow cylindrical body portion having a plurality of elongated circumferentially spaced slots therein, said slots terminating at one end in inclined surfacEs; a hollow cylindrical locking sleeve being supported upon said body in a concentric manner for sliding movement thereon in opposite directions and having a plurality of circumferentially spaced slots therein; a plurality of jaws having tangs received within said slots of said locking sleeve and being slidably received within said slots of said body portion whereby said jaws are movable with said locking sleeve; spring means for biasing said jaws radially outwardly into engagement with said inclined surfaces; said locking sleeve when respectively moved in opposite directions against the bias and with the bias of said spring means serving to expand and contract said jaws, respectively.

2. A lifting clamp, comprising: a hollow cylindrical body portion having a plurality of elongated circumferentially spaced slots therein, said slots terminating at one end in inclined surfaces; a cylindrical outer locking sleeve being supported upon and about said body in a concentric manner for sliding movement thereon between forward and retracted positions; a plurality of jaws pivotally supported upon said locking sleeve and being slidably received within said slots of said body portion whereby said jaws are moveable with said locking sleeve; and spring means for engagingly biasing said jaws radially outwardly into engagement with said inclined sur- faces; said locking sleeve when moved toward its retracted position against the bias of said spring means serving to expand said jaws and the bias of said spring means moving said locking sleeve when released toward its forward position in which said inclined surfaces engage and contract said jaws.

3. A lifting clamp, comprising: a hollow cylindrical body portion having a plurality of axially extending and circumferentially spaced slots therein, said slots terminating at a position adjacent one end of said body portion in inclined surfaces, said body portion having a radially outwardly extending lip adjacent said one end of said body, said body having means for attaching said lifting clamp to a lifting device; a hollow cylindrical locking sleeve having one end engaging said lip of said body and being supported thereby in a concentric manner upon said body for sliding movement thereon between forward and retracted positions, said locking sleeve having a plurality of circumferentially spaced slots therein; a plurality of jaws slidably received within said slots of said body for movement relative to said body with said locking sleeve, said jaws having a tang and a notch at their upper ends, said jaws having their lower ends formed in a hooked manner; a compression spring within said body having one end engaged within said notches of said jaws for biasing said jaws radially outwardly to maintain said hooked ends in engagement with said inclined surfaces during movement of said locking sleeve and jaws relative to said body and for maintaining said tangs of said jaws within said holes of said locking sleeve and said compression spring for biasing said locking sleeve toward its forward position whereby movement of said locking sleeve to its retracted position in opposition to the bias of said spring and to its forward position with the bias of said spring effects expansion and contraction, respectively, of said hooked ends of said jaws.