US3356406A

US3356406A - Lifting clamp

Info

Publication number: US3356406A
Application number: US464135A
Authority: US
Inventors: Josh L Renfroe
Original assignee: J C Renfroe and Sons Inc
Current assignee: J C Renfroe and Sons Inc
Priority date: 1965-06-15
Filing date: 1965-06-15
Publication date: 1967-12-05
Anticipated expiration: 1984-12-05
Also published as: DE1481801B1; NL144231B; BE682517A; GB1116248A; NL6608056A; DE1481800B1; JPS4841301B1

Description

5, 1967 J. L. RENFROE 3, I

LIFTING CLAMP Filed June 15. 1965 3 Sheets-Shet 2 gas 79 illl W HHHHH Him.

IN l [NTOQ Josh Lee Perz 1 7 06 ATTORNEYS Dec. 5, 1967 J RENFVRQE 3,356,406

LIFTING CLAMP Filed June 15, 1965 3 Sheets-Sheet 5 INV ENI' OR Jas/z Lee Razz/roe ATTORNEYS United States Patent 3,356,406 LIFTING CLAMP Josh L. Renfroe, Jacksonville, Fla., assignor to J. C. Renfroe & Sons, Inc., Jacksonville, Fla., a corporation of Florida Filed June 15, 1965, Ser. No. 464,135 13 Claims. (Cl. 294-101) This invention relates to clamps for use with structural members, and more particularly to hook-shaped clamps for use in lifting or sorting structural members.

When working with structural members, such as I- beams, H-beams, plates and the like, it is frequently necessary that the structural articles be lifted, stacked, unstacked, arranged into piles, or selected from a pile and moved to another location. Presently available clamps used to accomplish some of these functions are referred to as sorting hooks. The present clamp is useful as a sorting hook but it has other uses and is not restricted to sorting functions.

Conventional sorting hooks grasp an I-beam or the like at one end and can apply a pulling force only in a direction toward the other end of the beam. It is frequently desirable, however, to grip and hold a structural article in a variety of positions. For example, it may be desirable for a hook shaped clamp to grasp and hold a structural article with the lifting force acting parallel to and either inwardly or outwardly of the slot of the hook. In other situations it may be necessary for the same clamp to grasp and hold a structural article with the lifting force acting transverse to the slot. Thus if a sorting hook or similar clamp will grasp and hold a structural article only when the lifting force is applied in one direction the use of the sorting hook is limited.

It is therefore a primary object of this invention to provide an improved hook shaped clamp.

Another object of this invention is to provide a hook shaped clamp in which the force acting on the shackle to urge the jaws into gripping relation may be applied from various directions and still effectively grip the article to be moved.

A further object of this invention is to provide a hook shaped clamp having a horizontal slot in which the gripping force may be applied from either direction parallel to the slot and in any direction upwardly of the slot.

Other objects and advantages of this invention will become readilyapparent to those skilled in the art from the following description and drawings.

Generally, the invention which accomplishes the above objects and purposes may be described as a lifting clamp comprising a body including a horizontal slot for receiving a structural article, a cam jaw pivotally mounted in the body on one side of the slot to be pivoted into a gripping relation with an article in the slot, and a shackle pivotally mounted on the cam jaw to permit the shackle to pivot the cam jaw into the gripping relation when force is applied to the shackle upwardly with respect to the slot or in either direction parallel to the slot.

Preferably the cam is part of a cam jaw assembly including a cam jaw and a first pivot pin pivotally mounting the cam jaw to the body on one side of the slot. It is also preferred that the shackle be pivotally mounted on the cam jaw by a second pivot pin spaced from the first pivot pin to permit a force applied to the shackle in a direction which pivots the shackle away from the cam jaw to pivot the cam jaw to a gripping relation with a structural article in the slot.

It is preferred that the sorting book have an abutment means to be engaged by the shackle to permit a force applied to the shackle in a direction which urges 3,356,4fi6 Patented Dec. 5, 1967 the shackle into engagement with the abutment means to pivot the cam jaw into a gripping relation with an article in the slot. Desirably this abutment means is a surface which is a part of the cam jaw assembly. The surface on the cam jaw assembly which abuts the shackle is desirably either the first pivot pin or a portion of the cam jaw member itself.

The clamps of this invention may also include locking means connected to the cam jaw member for locking the cam jaw in gripping relation to an article in the slot.

The invention having been generally described, the preferred specific embodiments will be described in detail with reference to the accompanying drawings in which:

FIGURE 1 is a top plan View of a clamp constructed according to the invention;

FIGURE 2 is a vertical section of the clamp taken along line 22 of FIGURE 1;

FIGURE 3 is an end view of the clamp partially in section;

FIGURE 4 is a top plan view of a modified clamp constructed in accordance with the invention;

FIGURE 5 is a vertical section of the modified clamp taken along line 55 of FIGURE 4;

FIGURE 6 is an end view of the modified clamp;

FIGURE 7 illustrates the use of a pair of the clamps to lift a single horizontal I-beam; and

FIGURE -8 illustrates the use of the clamp to move a structural plate.

Referring now to the embodiment illustrated in FIG- URES 1 through 3, a body generally 10 is comprised of a pair of

body plates

12 and 14 spaced apart by

stiffener plates

16 and 18 which are welded or otherwise securely aflixed to the insides of

plates

12 and 14. Each of

plates

12 and 14 has a horizontal opening forming a horizontal slot 20 for receiving a structural article. It will be understood that such terms as horizontal and vertical are used to show the relationship of the parts with reference to a particular normal position of the clamp. Obviously the slot 20, for example, may be disposed at non-horizontal positions when the clamp is disposed at a position other than the reference position.

In accordance with this invention a cam jaw assembly is pivotally mounted in the body on one side of the slot. As here embodied the cam jaw assembly, generally 22, is mounted between

plates

12 and 14 at a position above horizontal slot 20. In the present embodiment the cam jaw assembly 22 includes a pair of spaced

cam jaws

24 and 26, having gripping edges 28, and a pivot pin 30 pivotally mounting

jaws

24 and 26 between

plates

12 and 14.

A shackle 32 having a lifting connection eye 34 is pivotally mounted on cam jaw assembly 22 by a pivot pin 36 which is vertically spaced below pivot pin 30. Pin 36 connects shackle 32 directly to

jaws

24 and 26.

Shackle 32 has an arcuate recess 37 for engaging the round pin 30 when the shackle is pivoted against pin 30. This groove permits eye 34 to be pivoted inwardly relative to the jaws 24 further than would be otherwise possible. It will be appreciated, of course, that the shape of shackle 32 may be varied in other ways to permit the eye to be pivoted to the desired position.

In accordance with the present invention means may be provided to lock the cam jaws in a gripping relation to an article in horizontal slot 20. As here embodied, the locking means is as follows. A U-shaped latch 38 is pivotally mounted on

body plates

12 and 14 by

pivot bolts

40 and 42 which are held in place by

nuts

41 and 43. A coil spring 44 is connected to the

jaws

24 and 26 by a pin 46 and to latch 38 by a pin 48 extending across the inside of the latch. A stop pin 50 is mounted between the

side plates

12 and 14 beneath latch 38. A chain 52 is connected to the end of latch 38. As may be seen, the lock is of the overcenter type, and is operated by pivoting latch 38 about

pivots

40 and 42 against the tension of coil spring 44 until pin 48 is lower than pivot pin 42. This movement of latch 38 causes spring 44 to pull latch 38 against stop pin 50. In this position, spring 44 urges

jaws

24 and 26 into slot 20 and thus causes the jaws to grip an article in slot 20. If desired, the lock may be omitted and the lifting force alone may be relied upon to provide the necessary gripping force on the article in the slot.

In use the clamp is placed on the structural article with a portion of the article extending into horizontal slot 20. The operator then pivots latch 38 to the locked position against pin 50 by pulling on chain 52. The

The cam jaw assembly is connected to ashackle, generally 80, having a pair of

arms

82 and 84 joined at a :lifting connection eye 86 at their upper ends.

Arms

82 and 84 straddle jaw 74 and are pivotally connected thereto by a pin 88 extending between

arms

82 and 84 and through jaw 74.

In accordance with the invention means may be pro-' vided for locking cam jaw 74 in a gripping relation with an object in slot 70. As here embodied, the means is comprised of an overcenter lock having a U-shaped latch 90 mounted on a pair of

pivot bolts

92 and 94 which are held in place by

nuts

93 and 95 respectively. A coil spring 96 is connected by an eyelet 98 to jaw 74 and by a pin pivoting of latch 38 applies tension to spring 44 which g in turn

pivots cam jaws

24 and 26 counterclockwise into an initial gripping relation with the article in slot 20. The lifting or moving force is then applied to shackle 32 as by a lifting cable or the like connected to eye 34 of the shackle and urges the jaws into a firm gripping relation with the article in the slot.

If the lifting or moving force is applied to the shackle in a direction parallel to horizontal slot and outwardly of the slot as indicated by arrow A in FIGURE 2, the force will tend to cause shackle 32 to pivot

jaws

24 and 26 further in a counterclockwise direction about pin 30 thus firmly gripping the article in horizontal slot 20. If this force is app-lied parallel to horizontal slot 20 in a direction inwardly of the slot as indicated 'by arrow B in FIGURE 2, the shackle will pivot about pin 36 until recess 37 engages pin 30. Pin 30 then acts as a fulcrum and shackle 32 acts as a lever which tends to urge pivot pin 36 outwardly of slot 20 in the direction indicated by arrow A. This outward movement of pivot pin 36 also urges

jaws

24 and 26 counterclockwise about pin 30 into a firm gripping relation with the article in the horizontal slot.

It will be appreciated that the force may also be applied to shackle 32 upwardly in different directions as indicated for example, by arrows C, D and E in FIGURE 2 and

jaws

24 and 26 will still be urged firmly against an article in the slot. The means by which the forceis transmitted to the jaws will depend on the direction of the force. If the force is applied in the direction indicated by arrows D and E, the force will simply cause the shack-1e to urge jaws counterclockwise. If the force is applied in the direction indicated by arrow C in the shackle will pivot against pin 30 and act as a lever to tend to urge pin 36 outwardly of slot 20 and thus pivot the jaws in the counterclockwise direction. The force may also be applied to the shackle downwardly as long as a moment arm is created between pin 36 and pin 30 or between eye 34 and pin 30. Thus the moving or lifting force may be applied to the shackle from any direction within an arc of more than 180 about the slot in the body of the clamp.

Referring now to the embodiment illustrated in FIG- URES 4 to 6, it may be seen that a body, generally 60, is comprised of a pair of spaced

plates

62 and 64 spaced apart by

stiffener plates

66 and 68. Each of the

plates

62 and 64 has a horizontal opening forming a horizontal slot 70 in the body for receiving a structural article.

In accordance with the invention a cam jaw assembly is pivotally mounted in the body on one side of the slot. As here embodied the cam jaw assembly generally 72 is pivotally mounted above horizontal slot 70 near the open end of the slot. As presently embodied the cam jaw assembly is comprised of a cam jaw 74, having a gripping edge 76, mounted on a pivot pin 78 extending between

side plates

62 and 64. Additionally the present cam jaw assembly includes a shoulder 79 on the upper end of cam jaw 74. The shoulder defines an arcuate bearing surface. Cam jaw 74 is free to pivot into and out of a gripping relation with an article in slot 70.

100 to latch 90. A chain 102. is connected to one end of latch 90. A stop pin 104 is provided to hold the latch in the locked position.

In the use of this embodiment, the clamp is placed on the structural article with a portion of the article extending into horizontal slot 70. The operator then pivots latch 90 to the locked position against pin 104 by pulling on chain 102. The resulting tension of spring 96 pivots cam jaw 74 counterclockwise into an initial gripping relation with the article in slot 70.

The moving or lifting force is then applied to shackle through means connected to eye 86. When this force is applied parallel to horizontal slot 70 in a direction outwardly of the slot as indicated by arrow X, the force is transmitted through

legs

82 and 84 of shackle 80 to pin 88 and tends to pivot jaw 74 counterclockwise about pivot pin 30 thus firmly gripping the article in the slot. If this force is applied parallel to slot 70 in a direction inwardly of the slot as indicated by arrow Y, the shackle will pivot about pivot pin 88 until the edge of eye 86 engages the bearing surface of shoulder 79 on jaw 74. The force acting on shoulder 79 through eye 86 then tends to pivot jaw 76 counterclockwise about pivot pin 78 and thus urges jaw 76 firmly into gripping relation with the article in the slot. It will be appreciated that the moving force may also be applied to the shackle upwardly and the jaw will be urged firmly into the gripping relation. The way in which the force is transmitted to the jaw will, as was indicated with regard to the first embodiment, depend on the direction of the force. Thus, forces having a component directed outwardly of the slot will cause the shackle to pull on pivot pin 88 to pivot the jaw counterclockwise while forces having a component directed inwardly of the slot will cause the shackle to press against shoulder 79 to pivot the jaw counterclockwise. The moving force may also be applied to the shackle in a direc tion downwardly of arrows X and Y as long as a moment arm is created between pivot pin 88 and pivot pin 78 or between shoulder 79 and pivot pin 78 and the force does not interfere with the article in the slot or is not blocked by the body of the clamp.

FIGURES 7 and 8 illustrate the clamp in use. As may be seen in FIGURE 7, a pair of clamps are being used to lift a horizontal I-beam. The upper flange of the I- beam is inserted into the horizontal slots of each of a pair of clamps with the web of the I-beam extending downwardly between the two spaced body plates of each of the clamps.

The latches of each of the clamps have been moved to the locked position to provide an initial grip on the I- beam. The lifting force, which in this use is being applied to the shackles upwardly and outwardly of the horizontal slots, urges the cam jaw assemblies into a firm gripping relation with the I-beam. The I-beam is thus held securely in a horizontal position by the two clamps.

FIGURE 8 illustrates the use of the clamp with the lifting force being applied inwardly of the slot. A single clamp is being used to lift a structural plate with the plate lying flat on a pallet or the like. The clamp has been placed on the plate with the plate extending into the slot which at that time was orientated horizontally. The lock was then moved to the closed position to provide an initial grip on the plate. The lifting force applied to the shackle was initially substantially perpendicular to the then horizontal slot and caused the cam jaw assembly to firmly grip the structure plate. As the lifting force pivoted the plate to the vertical position illustrated, the clamp also pivoted until its slot was vertical. Throughout the entire movement of the clamp the lifting force was transmitted to the cam jaw assembly and provided a firm grip on the plate.

Many modifications and variations of this invention will become apparent to those skilled in the art, and only such limitations should be applied as are contained in the appended claims.

What is claimed is:

1. A lifting clamp comprising:

a hook shaped body including a horizontal slot to receive an article;

a cam jaw assembly for gripping an article in the slot,

said cam jaw assembly including a cam jaw member and a first pivot pin pivotally mounting said cam jaw member to said body on one side of the slot;

a second pivot pin mounted on said cam jaw member and spaced from said first pivot pin;

and a shackle pivotally mounted on said cam jaw member by said sec-ond pivot pin to permit a force applied to said shackle in a direction which urges said shackle away from said cam jaw member to pivot said cam jaw member to a gripping relation with a structural article in the slot, said shackle and said cam jaw assembly being mutually engageable and said cam jaw assembly having a surface for abutting said shackle to permit a force applied to said shackle in a direction which urges said shackle into engagement with said cam jaw member to pivot said cam jaw member to gripping relation with a structural article in the slot.

2. A lifting clamp according to claim 1 wherein said surface for abutting said shackle is defined by said first pivot pin.

3. A lifting clamp according to claim 2 wherein the shackle includes a recess for engaging said first pivot P111.

4. A lifting clamp according to claim 1 including looking means connected to said cam jaw member for locking said cam jaw member in gripping relation to a structural article in the slot.

5. A lifting clamp according to claim 2 including locking means connected to said cam jaw member for locking said cam jaw member in gripping relation to a structural article in the slot.

6. A lifting clamp according to claim 1 wherein said surface for abutting said shackle is defined by said cam jaw member.

7. A lifting clamp according to claim 6 wherein said shackle includes abutment means for engaging said surface defined by said cam jaw member.

8. A lifting clamp according to claim 6 including locking means for locking said cam jaw member in gripping relation to a structural article in the slot.

9. A lifting clamp comprising in combination:

a hook shaped body including a pair of spaced side plates, said body defining a slot to receive a structural article;

a cam jaw for gripping an article in the slot, a first pivot pin pivotally mounting said cam jaw to said body on one side of said slot;

a second pivot pin mounted on said cam jaw and spaced from said first pivot pin;

and a shackle pivotally connected to said cam jaw by said second pivot pin, said shackle being free to engage said first pivot pin when pivoted toward said cam jaw to permit said cam jaw to be brought into gripping relation with a structural article in the slot either by a force urging said shackle away from said cam jaw or by a force urging said shackle against said cam jaw.

10. A lifting clamp comprising in combination:

a hook shaped body including a pair of spaced side plates, said body defining a slot to receive -a structural article;

a cam jaw member for gripping an article in the slot,

said cam jaw member having a shoulder and including a first pivot pin pivotally mounting said cam member to said body on one side of the slot;

a second pivot pin mounted on said cam jaw and extending through said cam jaw and spaced from said first pivot pin;

and a shackle pivotally mounted on said cam jaw member by a second pivot pin, said shackle being free to engage said shoulder when pivoted toward said cam jaw member to permit said cam jaw member to be brought into gripping relation with a structural article in the slot either by a force urging said shackle away from said cam jaw member or by a force urging said shackle against said cam jaw member.

11. A lifting clamp comprising a hook shaped body defining a horizontal slot to receive an article;

a cam jaw connected to said body by a first pin above the slot and being movable between an open and a gripping relation with an article in the slot;

a shackle positioned above the slot and connected to said jaw by a second pin above said slot, said second pin being vertically spaced from said first pin to permit a force applied to the shackle in one direction parallel the slot to bring said cam jaw to a gripping relation with the article in the slot;

and abutment means above said slot for engaging said shackle when said shackle is urged toward said abutment means to permit a force applied to said shackle in the other direction parallel to the slot to cause such shackle to engage said abutment means and bring said cam jaw to the gripping relation with an article in the slot.

12. A lifting clamp according to claim 11 wherein said abutment means is a surface on said first pivot pin.

13. A lifting clamp according to claim 11 wherein said abutment means is a surface on said cam jaw.

HUGO O, SCHULZ, Primary Examiner.

Claims

1. A LIFTING CLAMP COMPRISING: A HOOK SHAPED BODY INCLUDING A HORIZONTAL SLOT TO RECEIVE AN ARTICLE; A CAM JAW ASSEMBLY FOR GRIPPING AN ARTICLE IN THE SLOT, SAID CAM JAW ASSEMBLY INCLUDING A CAM JAW MEMBER AND A FIRST PIVOT PIN PIVOTALLY MOUNTING SAID CAM JAW MEMBER TO SAID BODY ON ONE SIDE OF THE SLOT; A SECOND PIVOT PIN MOUNTED ON SAID JAW MEMBER AND SPACED FROM SAID FIRST PIVOT PIN; AND A SHACKLE PIVOTALLY MOUNTED ON SAID CAM JAW MEMBER BY SAID SECOND PIVOT PIN TO PERMIT A FORCE APPLIED TO SAID SHACKLE IN A DIRECTION WHICH URGES SAID SHACKLE AWAY FROM SAID CAM JAW MEMBER TO PIVOT SAID CAM JAW MEMBER TO A GRIPPING RELATION WITH A STRUCTUREAL ARTICLE IN THE SLOT, SAID SHACKLE AND SAID CAM JAW ASSEMBLY BEING MUTUALLY ENGAGEABLE AND SAID CAM JAW ASSEMBLY HAVING A SURFACE FOR ABUTTING SAID SHACKLE TO PERMIT A FORCE APPLIED TO SAID SHACKLE IN A DIRECTION WHICH URGES SAID SHACKLE INTO ENGAGEMENT WITH SAID CAM JAW MEMBER TO PIVOT SAID CAM JAW MEMBER TO GRIPPING RELATION WITH A STRUCTURAL ARTICLE IN THE SLOT.