US2278717A

US2278717A - Solid wire and strand clamp

Info

Publication number: US2278717A
Application number: US344936A
Authority: US
Inventors: Richard H Burns
Original assignee: Indiana Steel & Wire Co
Current assignee: Indiana Steel & Wire Co
Priority date: 1940-07-11
Filing date: 1940-07-11
Publication date: 1942-04-07
Anticipated expiration: 1959-04-07

Description

Ami 17,1942. R. H. BURNS I "2,273,717

SOLID WIRE AND STRAND CLAMP Filed July 11, 1940 INVENTOR. Paw/720 5019/5,

Patented Apr. 7, 1942 UNITED STATE-S PATENT OFFICE SOLID WIRE AND STRAND CLAlI/IP Richard Burns, Muncie, 11141., assignor to Indiana Steel & Wire Company, Muncie,JIml., a corporation of Indiana Applicationaluly .11, 1940, Serial No. 344,936 1 7 Claims.

.My invention relates to. clamps .of the type commonly "used to form eyes in wire cables or single-strand wires. It is the object of :my invention to produce a clamp of this type which will have a materially greater holding power than will any prior clamps of which I am aware.

A clamp embodying my invention includes a single elongated back pl-ateprovided with parallel cable-receivinggrooves, :a plurality of shorter front plates each of which is also provided with parallel cable-receiving grooves, and means such as a boltacting'be'tween the back plate and each of the front plates to draw the two plates toward each other and clamp the cable between them.

The accompanying drawing illustrates my invention: Figs. 1 and 2 are, respectively, a plan and an elevation of my .clamp used to form an eye .in awire cable; and Fig. 3 is an end elevation of the clamp.

As will be clear from the drawing, the clamp comprises :a unitary back plate Ill and a plurality of individual front plates II disposed in opposed relation .to the back plate. At or near the longitudinal center-line of the clamp, the back plate and each of the front plates are provided with alined holes [3 for the reception of clamping means shown in the drawing as a bolt I2. In addition, each of the plates, both front and back, is provided with a pair of parallel longitudinal grooves I4 of arcuate cross-section adapted to receive a cable of the size with which the clamp is to be used,-

In the particular arrangement illustrated in the drawing, the clamp is employed to form an eye in a cable I5. The body of the cable extends through one set of opposed grooves and around a thimble l6, the end I! of the cable extending through the other set of opposed grooves in the clamping plates. By tightening the bolts I2, the cable is firmly secured in place.

I find that a clamp constructed as described has a materially higher holding power than has a clamp consisting of a single pair of opposed plates, even though both clamps may embody as many clamping bolts and be of the same length. I believe this to be due to the fact that each of the individual front plates II is free to swing relatively to the back plate about the axis of its associated bolt I2 except as limited'by the presence of the cable within the plate-grooves.

When the clamp is used to form an eye, as

in the drawing, or when it is used to interconnect the adjacent ends of two cables subjected to tension, tension in each of the two stretches gripped by the clamp will tend to rotate each of the individual plates H about the axis of its associated bolt I2 in the same direction. Thus, in the specific arrangement illustrated in the drawing, tension applied to the cable l5 and resiste'd by .force applied to the 'thimble I6 will tend. to rotate each of the individual front plates .1 I in a counterclockwise direction relative to the back plate HI; "and this is true not only of the tension in the body of the cable I5 but also of the tension in the cable-end II, although the 1 latter tension will be ;much smaller than the former because of friction between the cable and the :thimble. I

Rotation .of each front plate relative to the back plate is limited by. reason of the presence of the cable in the grooves of the two plates;

and in opposing plate-rotationthe cable is subjected to a clamping action exerted by the side walls of. .the cable-receiving grooves as at the points a. and b in Fig. 3. Because each of the front plates is relatively short, the forces applied to the cable at the points a .and b are relatively large and effective in gripping the cable. Moreover, since the cable-gripping effort resulting from the tendency of the front plate to rotate is caused by-tension in the cable it will increase as the tension in the cable increases. This is in contradistinction to the conventional form of clamp in which the entire gripping effort results from the tightness of the. clampbolts; for in a clamp of that kind tension in the cable tends to reduce its diameter and thereby to lessen the gripping efiort.

In order to prevent crushing of the cable by the action of the clamp bolts and to promote uniform distribution of clamping effort among the several strands of the cable it is advisable in most instances that the length of each of front plates I I be not materially less than one-quarter the lay of the cable. I prefer to employ a back plate l0 having a length about equal to the lay of the cable and to use either two or three of the front plates II; but thearrangement is susceptible of considerable variation. While I have illustrated and described the clamp as for use with cable, it will be obvious that it may also be employed with solid wire.

It is to be noted that the above described clamping effect resulting from the tendency of the front plate to rotate occurs at each front plate and that the aggregate clamping effect is the sum of the individual effects. Under test, the cable will not slip in my clamp even when subjected to suficient tension to break it. With a conventional two-plate clamp of comparable size and the same number of clamp bolts, it is impossible, on the average, to subject the cable to much more than half the tension required to break it; because slippage of the cable in the clamp will occur.

I claim as my invention:

1. A clamp of the type described, comprising an elongated back plate and a plurality of individual front plates, said back plate and each of said front plates being provided in their opposed faces with two laterally spaced, parallel, cable-receiving grooves extending longitudinally of the back plate, and a single bolt extending through each of said front plates and said back plate and disposed intermediate the two grooves therein.

2. A clamp of the type described, comprising an elongated back plate and a plurality of individual front plates, said back plate and each of said front plates being provided in their opposed faces with two laterally spaced, parallel, cable-receiving grooves extending longitudinally of the back plate, each of said front plates being rotatable relatively to said back plate about an axis per- 3. A clamp of the type described, comprising an elongated back plate and a plurality of individual front plates, said back plate and each of said front plates being provided in their opposed faces with two laterally spaced, parallel,

cable-receiving grooves extending longitudinally 0f the back plate, each of said front plates being rotatable relatively to said back plate about an axis perpendicular to the two plates, and clamping means acting between the back plate and each of the front plates for forcing them toward each other.

4. A clamp of the type described, comprising an elongated back plate grooved in its front face to support two cable stretches in parallel relationship extending longitudinally of the back plate, a plurality of individual front plates in opposed relation to said back plate, and clamping bolts between the two cable stretches for forcing said front plates toward said back plate to clamp the cable, at least one of said front plates having a single clamping bolt passing through it and being angularly movable relative to said back plate about the axis of such single bolt.

5. A clamp of the type described, comprising an elongated back plate grooved in its front face to support two cable stretches in parallel relationship extending longitudinally of the back plate, a plurality of individual front plates in opposed relation to said back plate, and a single clamping bolt associated with each front plate and disposed between the two cable stretches for forcing the associated front plate toward the back plate to clamp the cable.

6. A clamp of the type described, comprising an elongated back plate grooved in its front face to support two cable stretches in substantially co-planar relationship and to confine such cable stretches laterally, a plurality of individual front plates in opposed relation to said back plate, and clamping bolts between the two cable stretches for forcing said front plates toward said back plate to clamp the cable, at least one of said front plates having a single clamping bolt passing through it and being angularly movable relative to said back plate about the axis of such single bolt.

'7. A clamp of the type described, comprising an elongated back plate grooved in its front face to support two cable stretches in substantially co-planar relationship and to confine such cable stretches laterally, a plurality of individual front plates in opposed relation to said back plate, and a single clamping bolt associated with each front plate and disposed between the two cable stretches for forcing the associated front plate toward the back plate to clamp the cable.

. RICHARD H. BURNS.