US2905035A - Friction wrench - Google Patents

Description

Sept. 22, 1959 i J. A. PETERSON ETAL 3 FRICTION WRENCH Filed March 18, 1957 Can/.5 OLseu ATTOR EY United rates atent FRICTION WRENCH Joseph Arvid Peterson and Carl E. Olsen, Houston, Tex. Application March 18, 1957, Serial No. 646,840.

4 Claims. (Cl. 81-.-67)

The invention relates togripping devices or wrenches and more. particularly. to gripping. devices of. the type adaptedto. tightly and frictionally embrace cylindrical objects such as pipes or bars.

In thepast, gripping devices, of the above type, have normally been equipped with somewhat complicated and inconveniently operated structures for locking or retainingthe. device in its work holding position. Some attempts have been made to. develop more conveniently operable locking means for gripping devices,.however, such previous attempts have resulted in unduly expensive and/or extremely. complicated structures.

Accordingly, it is a principal objectof the invention to 'provide a novel gripping device particularly adapted to be. readily engaged to .a cylindrical object for applyingor resisting torques on the object.

Afurther object isto provide an inexpensive gripping device adapted to .be. conveniently handled and operated.

Another. object. resides in the. provision of a gripping device, characterized by a novel friction locking arrangement whose locking action is enhanced upon the application of torque to .thecmbraced object.

Further objects and advantages of the invention will'be in part obvious and in part pointed out hereinafter.

The novel features of the inventionmay be best made clearwfrom the following description and accompanying drawings in which:

Fignrel is a fragmentary side elevational view of a gripping device of the invention;

Figure. 2 is a fragmentary top plan view of the device;

Figure 3 is a bottom plan view of the device;

Figure 4 is a view of a jaw of the device taken in the direction of the adjacent arrow;

Figure 5 is a view of the device taken in the direction of the adjacent arrow; and

Figure 6 is a perspective view, partially in section, showing the details of a locking bolt illustrated in Figure l.

Referring to thedrawings, a gripping device of the invention preferably includes a main handle 10 and a girth 12 pivoted to the main handle. The girtltlZis adapted to embrace a cylindricalwvork object 14 and preferably comprises a plurality of pivotall y intercon nected jaws 16, 18, 2d pivoted to an outer free end of the main handle for bodily swinging movement with respect thereto. Each of the jaws 16, 18, Zdand the main handle lil maybe constructed of any suitable metal such as aluminum, and these parts may he formed by anydesirable process, such asforging or casting.

The first jaw 16 (Figure 4) may be composed of two longitudinal, generally symmetrical sections 22, 24 connected togetheras by transverse rivet 26 and/ or welding along the seam 28 therebetween. The top of the jaw preferably is provided with transversely spaced apeltured cars 30; The joined sections 22, 24 form lug 32 projecting laterally outwardly from jaw 16 and having a verticallyf disposed blind hole 34 therein. This jaw 16 is pivotally connected to the forward--01? left end of main ice 2 handle '10 as viewed in Figure 1. For the tfiorwardpurpose, this end of the handle 10 may be formed with a downwardly opening arcuate concavity 36 therein for receiving a pin or bolt 38 extending through the apertured cars 30 of jaw 16. The handle 10 and. pin 38 may also be drivingly and fixedly connected together as by means of an interlocking pin 40 suitably retained in alignedholes in the handle 10 and bolt 38. If desired, bolt 38 may be integral with the handle 16- constituting trunnions extending laterally from either side thereof for j ournalling in ears 30.

The lower end of the jaw 16 is suitably pivotally connected to the intermediate jaw 18, as by being bifurcated into apertured portions 42 adapted to be fitted over a transversely bored end 44 of reduced width on jaw/ 18 (Figure 5) and engaged thereto by a pivot pin 46 extending through these portions 42 and the end 44. To limit the relative pivotal movement between jaws 16, 18 inan opening direction, a lug 48 may be formed on the end 44 of. jaw 18 for engagement with a stop surface 50 recessed in the jaw 16. Cooperating, transversely extending arcuate surfaces "52, 54 are respectively formed in the jaws 16, 18 for receiving the cylindrical work piece 14. j

The upper end of jaw 16 may also be bifurcated into apertured portions 56 adapted to be fitted over a trans versely bored portion of jaw 26 and engaged thereto by pivot pin 58 extending through the aligned apertures and bore.

The jaw 20 preferably includes a hand grip section 69 extending rearwardly and integrally therefrom to constitute a secondary handle for the gripping device, of smaller length than main handle 16? (as seen in Figure l). A transverse surface 62 is formed in jaw 26 for cooperation with surfaces 52, 54 of jaws 16, 18 respectively to completely embrace the work piece 1d when the jaws are closed. The axial length-of this surface 62 may be increased by forming arcuate, lateral extensions. 64 on jaw 20. Relative pivotal movement between jaws 18, 21 in an opening direction, may be limited by the provision of a stopsurface 66 on the underside of jaw 26 adjacent pivot pin 58engageable with a complementarily shaped surface 68 on the jaw 18.

The invention contemplates the provision of novel lockingmeans for retaining the jaws 16, 18, 20 in closed position, wherein they tightly embrace the cylindrical work piece 14. An exemplary embodiment of such means includes mutually engageable, friction locking surfaces on the bolt 38 and'free, inner end of jaw 20, and biasing means continuously urging the jaws 16, 18, 20 to pivotor swing bodily toward the main handle 10. These engageable, locking surfaces preferably are defined by a pair of side walls which diverge outwardly from adjacent the central axial region of bolt 38 to form a longitudinally extending recess or notch 70 for receiving a transverse lip 72 projecting outwardly from inner end of jaw 20 andapproximately at a right angle to the longitudinal axis of the jaw. The biasing means preferably includes a compression spring '74 arranged in the blind hole 34- in the lug 32' of jaw 16for acting against an arcuate finger-like projection orprotuberance 76 on the adjacentend'of main handle Ill. The outer end of this finger 76 is disposed in the upper end of the hole 34 and a pin 78 is continuously pressed thereagainst by the spring.

In the operationof our novel gripping device, the jaws of the girth 12 are readily moved to an open position by manual operation of handles 10, 60 and the cylindrical work piece 14 is disposed therewithin. The jaws are thereafter moved to their closed position wherein the surfaces 52, 54, 62 therein engage the surface of the work piece. The surfaces 52, 54, 62 preferably are relatively smooth whereby they may tightly embrace the recess 70 of bolt 38, wherein the lip 72 will be engaged to the right hand inclined surface of this recess as 'viewed in Figure 1. At this time the jaws 16, 18, 20 will be desirably locked in closed position, tightly embracing the work piece whereby the gripping device may be effectively utilized for applying or resisting torques or other forces on the workpiece.

The action of the compression spring 7 3 will be seen to cause the main handle 10 and girth 12 to tend to swing or pivot toward each other. This tendency of these parts to swing toward each other takes place about the axis of bolt 38. The secondary handle 60 and jaw 20 will be prevented from swinging in a counter-clockwise direction about the axis of pivot pin 58 by reason of the presence of the work piece 14, acting as an abutting or stop surface for such swinging movement. Consequently, the tendency of these parts to swing together, produced by the action of spring 74, will result in the development of a force in the region of contact between the lip 72 and recess 70, and acting on the lip 72 in a direction generally normal to the right hand surface of recess 70 and downwardly to the left, as viewed in Figure 1. It will be evident that such a force will produce a tight, positive friction lock on the workpiece 14 by the jaws 16, 18, 20. In this connection, if the operator holds only the main handle 10 at the outer end thereof, the weight of the jaws will result in a generally downwardly directed force pulling on the jaws, tending to produce a clock-wise bodily swinging thereof about the axis of bolt 38 away from handle 10. However, the compression spring 74 is designed so that the magnitude of the forces produced thereby, tending to cause the pivoted jaws to swing bodily toward the main handle will be suflicient to overcome the tendency of the jaws to swing away from the main handle, whereby the force referred to above acting on the lip 72 of jaw 20 will still be developed for assuring the desired tight friction lock of the jaws on the work piece. Furthermore, it should also be evident that movement of main handle 10 by the operator in a counterclockwise direction about the axis of the cylindrical work piece 14 will initially eifect an inward movement of the projecting finger 76 thereon further into the blind hole 34 whereby the compression of spring 74 will be increased, thereby causing a corresponding increase in the magnitude of the force acting on the pivoted jaws to produce a bodily swinging of these jaws toward the main handle while imparting a corresponding counter clockwise torque and movement to the work piece 14. Clockwise swinging of main handle 10 to turn the work piece 14 in a clockwise direction will be noted to cause bolt 38 to be rotated or moved therewith so that the surface of recess 70 engaging lip 72 will be driven into tighter engagement with lip 72, thereby preserving and actually enhancing the gripping action of the jaws.

It will be understood, that the girth 12 is not adapted for all sizes of cylindrical work objects, although some variation in diameter can be accommodated by the pivoted jaw assembly inasmuch as the jaw 20 and secondary handle 62 will be in locked position virtually as soon as the lip 72 on jaw 20 enters the recess 70, wherein the circircumferential distance defined by the cooperating surfaces 52, 54, 62 of the jaws will be the greatest, and the jaws will also be locked for all positions between this initial locked position and a final position of the jaw 20, wherein the secondary handle will be generally parallel to the main handle 10 and the lip 72 will be disposed at the innermost portion of the recess 70, this latter position involving the maximum closing movement of jaw 20 toward jaws 16, 18 thereby presenting the smallest circumferential distance defined by the cooperating surfaces 52, 54, 62. In the maximum closed position of jaw 20, the lip 72 thereof will be disposed at the innermost portion of recess 70 whereby any force applied downwardly at the outer endof main handle 10, due to the large lever or moment arm of handle 10 and the small moment arm for the reaction force on lip 72 (both moment arms being measured to the axis of bolt 38), will result in a greatly amplified force acting on lip 72 to urge the jaw 20 toward jaws 16, 18. It will also be appreciated that the tightening or gripping action can be increased by moving handle toward handle 10 so that the gripping device will operate effectively even with small work pieces having slippery or smooth outer surfaces.

It will be apparent that in imparting torque to the work piece 14 the operator may grasp both the main handle and the secondary handle. The secondary handle has been found to greatly facilitate the opening and closing of the girth 12, and in this regard, it will only be necessary to apply opposite outwardly directed forces to the main handle 10 and secondary handle 60 to separate them for removal of the lip 72 from the recess 70 whereby the girth may be opened to release its grip on the work piece.

When the gripping device is utilized for resisting external forces applied to the work piece 14, it will be noted that any external counterclockwise torque applied to the work piece (as viewed in Figure 1), that is, a counterclockwise torque not exerted on the work piece 14 by the gripping device, will initially tend to produce a bodily swinging of the pivoted jaws toward the main handle which is held stationary by the operator. This tendency of the jaw assembly to swing toward the main handle will increase the contact force between lip 72 and the engaged surface of recess 70 whereby the jaws will be pressed more tightly against the work piece to resist and prevent rotation thereof. If an external clockwise torque is applied to the work piece, the pivoted jaw assembly will then initially tend to swing bodily away from the main handle 10. However, this tendency will be overcome by the additional compression of spring 74, occasioned by any bodily movement of the jaws away from the handle 10, which will be effective to prevent disengagement of the lip 72 from recess 70, thereby keeping the jaws in closed position.

It will thus be seen that the objects of this invention have been fully and effectively accomplished. It will be realized, however, that the foregoing specific embodiment has been shown and described only for the purpose of illustrating the principles of the invention and is subject to extensive change without departure from such principles. Therefore, this invention includes all modifications encompassed within the spirit and scope of the appended claims.

We claim:

1. A gripping device comprising: a main handle having a forward end portion; a jaw assembly having a plurality of pivotally interconnected jaws with cooperating surfaces for embracing an object when said jaws are pivoted toward each other into closed position; said jaw assembly having one end thereof pivoted on a transverse axis to the 7 forward end portion of said main handle and an opposite free end movable toward said main handle; biasing means acting between the pivotally connected end of said jaw assembly and the forward end portion of said handle for continuously urging said jaws toward said main handle; cooperable means including a transverse locking recess formed in said main handle adjacent the transverse axis about which said jaw assembly pivots and a transversely extending projection carried by said jaw assembly adjacent the free end thereof arranged for interlocking frictional engagement with said locking recess when said jaws are moved into closed position; and a secondary handle connected to said jaw assembly and movable therewith to a locking position adjacent said main handle for first closing and then locking said jaws.

2. The structure defined in claim 1 wherein the pivotally connected end of said jaw assembly is provided with a hole therein, a protuberance formed on said handle adjacent the forward end thereof, normally projecting into said hole, and a compression spring disposed in said hole acting in opposite directions against said protuberance and said jaw assembly.

3. A gripping device comprising: a main handle having a forward end portion; a jaw assembly including pivotally interconnected first, second, and third jaws, each having cooperating curved surfaces for embracing a substantially cylindrical object when said jaws are pivoted toward one another into closed position; said first jaw being pivoted on a transverse axis to the forward end portion of said main handle; said second jaw being respectively pivoted at each end thereof to said first and third jaws; said third jaw including a free end; a secondary handle connected to said third jaw at the end thereof opposite said free end for moving said jaws into closed position; biasing means acting between said first jaw and the forward end portion of said main handle for continuously urging said jaws toward said main handle; and cooperable means including a transverse locking recess formed in said main handle adjacent the transverse axis about which said first jaw pivots and a transversely extending projection carried by said third jaw adjacent the free end thereof arranged for interlocking frictional engagement with said locking recess for retaining said jaws in closed position.

4. The structure defined in claim 3 wherein the continuously biasing means includes: an arcnate fingerlike protuberance on the forward end portion of said main handle adjacent said first jaw, said first jaw being formed with a laterally protruding portion adjacent said handle and having a hole therein, the outer end of said protuberance being disposed in said hole, and a compression spring in said hole acting in opposite directions against said first jaw and said protuberance.

References Cited in the file of this patent UNITED STATES PATENTS 1,243,543 Moran Oct. 16, 1917 1,764,124 Smith June 17, 1930 2,329,196 Hambly Sept. 14, 1943 FOREIGN PATENTS 214,541 Great Britain Apr. 24, 1924

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