US2244533A - Clamp - Google Patents

Description

June 3, 1941. F. FLETCHER CLAMP Filed Aug. 26, 1940 INVENTOR FPflN/f N. FLETCHER A TTORNE Y5 Patented June 3, 1941 UNETED STATES TENT @FFEQE CLAMP Frank N. Fletcher, Valdosta, Ga, assignor of onehalf to William G. Eager, Valdosta, Ga.

3 Claims.

My invention relates to an improved clamp which is adapted to lift or haul timber, pipe and the like and embodying a rope, cable or chain for pulling 0r lifting the work, and has for an object the provision of a clamp in which the pull on the pulling member serves to secure the clamp to the work.

Another object is to provide a clamp which is frictionally secured to the work by threading a,

pulling member such as a rope, cable or chain back and forth over the work in such a manner that the harder the pull on the pulling member the tighter the clamp is secured to the work.

A further object is to provide a clamp which is slidable on the work when the pulling element is not in tension, and which is easy to secure around and remove from the work and, at the same time, is positive in its clamping action when in use.

A further object is the provision of a clamp which is provided with a plurality of rollers, under which is threaded the pulling element, which then passes over the work so that the maximum gripping effect is obtained from the tension on the pulling element to secure the work to the clamp.

A still further object is to provide a clamp for lifting or dragging timber, pipe and the like, which is capable of effectively clamping timber,

pipe and the like of varying diameters and which comprises but a single unit with no separable parts. I

Briefly, my improved clamp comprises an elongated frame having a central member in the form of a cradle for receiving the work to be pulled or lifted. Spaced on either side of the cradle is a beam which is secured to the cradle by means of transverse through bolts. Spaced at intervals along the length of the frame between the cradle and the beams, and alternately on either side of the cradle, are a number of small rollers which are rotatable on the through bolts. The through bolts are passed through a number of spacer blocks which serve to hold the beams in spaced relation with respect to the central member. A pinis provided at the rear of the clamp and is adapted to receive one end of a flexible pulling element which is threaded alternately over the work and under the rollers so that when the free end of the pulling element is put in tension the work is securely held. The rollers permit the pulling element to tighten about the work without friction so that the harder the pull, the tight er the work is gripped to the clamp. If it is desired to slip the clamp to a new position on the work or to remove it therefrom, it is only necessary to slacken the pull on the pulling element, whereupon the clamp is free to slide along the work.

A clamp embodying features of my invention is illustrated in the accompanying drawing forming a part of this application, in which:

Fig. 1 is a plan view illustrating a piece of work secured to the device;

Fig. 2 is a side elevation of the same; and

Fig. 3 is a sectional view taken on line III--III of Fig. 1.

Referring to the drawing for a better understanding of my invention, the clamp comprises a frame having a central member H and .end members i2 and I3 forming a cradle adapted to receive a piece of work it which obviously may be any elongated body such as timber, pipe, rods or the like adapted to fit in the clamp and which it is desired to pull or lift. The central member ll has a curved work receiving face It; and the members l2 and it are likewise curved as at I! and IE to receive work of larger diameter.

On either side of the member I! and held fast thereto by a plurality of through bolts 19 I mount beam members 2| and 22. Spacers 23 are provided between he member II and the members 2| and 22 so as to provide spaces 24 and 216 between the beams and the central member. Spaced along the length of the frame on alternate sides of the member II and fitting in the spaces 24 and 26, I mount a plurality of small rollers Z'l, each of which takes a bearing on one of the through bolts l9 as shown. These rollers are freely rotatable on the bolts l9 and are positioned below the work receiving face it of the member H in order to be out of the way of the work It.

At the end of the clamp removed from the direction of pull, which I call the rear end, is a headed pin 23 about which is tied one end of a flexible pulling element, such as a rope 29. As seen in the drawing, the element 29 passes over the work It under the rollers 2'7 so that when its free end 3! is put in tension the work is drawn tightly to the clamp and is held there by friction between the pulling element 29 threaded over a pipe and under the rollers 21. As soon as the pulling force is applied, the pulling element 2% immediately tightens and draws the clamp and pipe together so that friction between the rope and pipe and between the member Ii and the pipe prevents the clamp from slipping. The rollers 21 materially aid this gripping effect because the pulling element 29 is perfectly free to tighten about the pipe as it does not bind against any parts of the clamp. When it is desired to loosen the clamp either for the purpose of removing it or allowing it to slip to another place on the work, it is only necessary to remove the tension from element 29 whereupon the clamp readily slips down on the work. When the tension is again applied the pulling element readily tightens about the work as explained.

While I have shown the pulling element as being a rope, it will be apparent that depending upon the strain and character of work to be done, any member of like flexibility, such as a chain or cable, may readily serve this purpose equally as well. Likewise, while I have described the lifting operation as employing only one of my improved clamps, it will be apparent that a plurality of them may be applied to a single piece of work. In fact, when lifting extremely long pieces of work, I have found it advantageous to use two of the clamps with two lifting elements so that when the top one comes adjacent the hoisting tackle the lower one may be used to hold the work until the upper one is dropped to a lower position.

While I have shown my invention in but one form, it will be obvious to those skilled in the ,art that it is not so limited, but is susceptible of various changes and modifications, without departing from the spirit thereof, and I desire, therefore, that only such limitations shall be placed thereupon as are imposed by the prior art or as are specifically set forth in the appended claims.

What I claim is:

1. A device of the character described, comprising an elongatedframe for receiving a piece of work, bearings spaced along the length of the frame on the sides thereof, rollers on said bearings, and a flexible element having one end secured fast to the device and passing over the work and under the rollers to clamp the work to the frame responsive to lifting force being applied to the other end of said flexible element.

2. A device of the character described, comprising an elongated frame for receiving a piece of Work, side members spaced from the frame, spacers holding said frame and said side members in spaced relation, transverse through bolts holding the several parts assembled, a plurality of rollers spaced along the frame on either side thereof and rotatable on said bolts, and a flexible pulling element threaded over the work and under the rollers to clamp the work to said frame responsive to pulling force being applied to said element.

3. A device of the character described, comprising an elongated frame having a concave face adapted to receive a piece of Work, side members spaced from said frame, bearings adapted to receive rollers spaced along the length of said frame between the frame and the side members, rollers on said bearings, and a flexible element having one end fast to the device and threaded over the work and under the rollers to clamp the work to the frame when force is applied to the free end of the flexible element.

FRANK N. FLETCHER.

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