Abstract:
A clamp for rotating the adjustable mechanism of a hand tool to open and close it. The clamp including spring biased arms forcing upper jaws toward each other to engage the hand tool and a lower shaft engageable with a drive socket of a power tool. The clamp comprising two clamp arms that are spring biased to force the jaws toward each other for gripping the adjustable mechanism of a hand tool. The clamp capable of rotating the hand tool to tighten or loosen it depending upon the rotation of the drive socket.

Description:
BACKGROUND OF THE INVENTION 
     The invention in general is directed to providing an aid to operate to close or to open hand tools, and the like, that would otherwise require repetitive turning motions by hand. Specifically, the invention is directed toward an accessory clamp that may be rotated by a cordless drive device for opening and closing hand tools such as C-clamps, vises, vise grips and the like. 
     Various hand tools require tightening by means of turning a helical threaded shaft for closing jaws or other gripping portions, such as C-clamp or vise grips. It is necessary to rotate these threaded portions by hand to the closed or open position. This activity is required for the amateur hobbyist, homeowner/do-it-yourself worker, as well as professional craftsmen and skilled artisans. The task of opening and closing these clamping-type devices is time consuming and requires repetitive rotating motions which often require two hands and can be the source of tendinitis or other musculoskeletal debilitations. 
     Accordingly, it is a primary goal of the invention to provide a clamp for releasably attaching to the locking portions of a hand tool and having the capability of being drivingly attached to a powered driver for rotation of the tool&#39;s adjustable mechanism of the type that is normally turned by hand. 
     It is a further goal of the invention to provide an accessory clamp which resiliently grips a rotatable portion of a hand tool for closing and opening it and includes a driveable shaft engageable with the drive socket of a power source, such as an electric screwdriver or drill. 
     It is also a goal of the invention to provide a clamp engageable with a drive socket of a cordless electric power tool, such as a cordless drill or screwdriver operating at low RPM&#39;s and relatively high torque for operably rotating the threaded adjustment member of a hand tool. 
     It is another object of the invention to provide a drive socket-engageable portion of an accessory clamp that includes an overload release to prevent the motor of the power source from operating against a jammed or locked tool held by the tool gripping portion of the accessory clamp. 
     It is yet another allied goal of the invention to provide for an accessory clamp for gripping, at one end, the rotatable portion of a tightenable hand tool at opposing gripping jaws capable of engaging a variety of configurations for the hand-adjustable tightening portions of various hand tools, and at the other end being capable of attachment to a cordless power tool for the driving rotation thereof. 
     It is further an auxiliary objective of the invention to provide for an accessory clamp that includes opposing jaw-like members that float loosely relative to each other to compensate for and grippingly accommodate variously shaped hand tools. 
     SUMMARY OF THE INVENTION 
     The invention may be summarized as a hinged accessory clamp having a pair of re-bent arms spring biased together to provide for two opposing upper surfaces holding gripping jaws for attachment to the operable mechanism of a closable hand tool, or the like. The hinge is at a clamp end opposite the jaws and includes an open tubular member for receiving a shaft to be fastened therein. The shaft being engageable, for example, with a hex drive of an electric power tool for the driving rotation thereof. The shaft further includes anti lock-up means, preferably in the form of biased retractable ballbearings, to prevent the locking-up or freezing when the limit of travel of the hand tool adjustment is reached. 
     The opposing gripping jaws are loosely held to be able to float opposite each other in relative independent motion to accommodate for deformities or odd-shaped engageable portions of a hand tool. The re-bent arms of the clamp are pivotally joined at lower arm portions thereof at the hinge and are resiliently biased by a compressed spring. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is an exploded side view of the accessory clamp arranged below a pinned threaded rod of a C-clamp and above the hex drive socket of an electric power tool; 
     FIG. 2 is a front view of the accessory clamp looking from the left-hand side of FIG. 1; and, 
     FIG. 3 is a top view of the accessory clamp looking into the jaws thereof. 
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENT 
     With respect to the drawings, like reference numerals are used throughout to refer to the same elements. 
     In FIG. 1, the preferred embodiment for the accessory clamp of the invention is generally denoted at 10. The accessory clamp 10 is intended for temporary clamping engagement to work tools, preferably hand tools of the type that are tightened or loosened by the person rotating a threaded shaft, such as a C-clamp 11. The C-clamp 11 includes a threaded shaft 12, thread engaging a clamp frame 13 and a transverse pin 14 used by the operator for grasping and turning the shaft 12 clockwise or counterclockwise for loosening or engaging the clamp 11 in a known manner. The accessory clamp 10 is driveable by an electrical power driver or tool, preferably of the cordless variety, as generally denoted at 15, which has a drive-engage, able socket 16. In the preferred embodiment the socket 16 is a hex drive socket commonly found in hand-held cordless electric screwdrivers and drills. When accessory clamp 10 clampingly engages the pin 14 of C-clamp 11 at one end thereof and is inserted in the hex drive socket 16 of the power driver 15 at the opposite end thereof, actuation of the power drive 15 will rotate the accessory clamp 10 and thereby the threaded shaft 12 either clockwise or counterclockwise, as desired, to open or close the C-clamp 11. 
     With more specific derailed reference, the accessory clamp 10 disclosed is primarily comprised of opposingly arranged wide arms comprising a main clamp arm 17 and secondary clamp arm 18. The clamp arms 17 and 18 are hinged at 19, as will be further explained hereinafter. With reference to FIGS. 1-3 collectively, it will be seen that the secondary clamp arm 18 includes a pass-through slot 20 through which the main clamp arm movably resides. The clamp arms 17 and 18 have opposing upper arm portions 21, 22, with opposingly directed flanges 23, 24, respectively. The opposing upper arm portions 21, 22 loosely retain clamping jaws 25, 26, respectively, facilitating the gripping of a hand tool adjustment means, such as pin 14. The clamping jaws 25, 26 are retained by rivet fasteners 27, 28, respectively, loosely attaching, or tethering, them to the opposing upper arm portions 21, 22. Thereby, the gripping jaws 25, 26 are in a floating condition allowing for various shapes and angular differences to be accommodated for attachment to the operable adjustment portions of hand tools and the like. The opposing flanges 23, 24 are formed at fight angles to the upper arm portions 21, 22, respectively, and are provided to keep the gripping jaws 25, 26 from turning or slipping upwardly out of clamping engagement. The gripping jaws 25, 26 are formed with recessed flats 29, 30 to accommodate and clear the rivets 27, 28, respectively. The gripping jaws 25, 26 extend transversely outward from, and have a greater width than, the clamping arms 17, 18, as best viewed in FIGS. 2 and 3, whereby to be able to surely grip a variety of rotatable tightening means of hand tools, such as butterfly-shaped grips, elongate pins, knobs, hex nuts, wing nut shapes, and the like, as would be understood by one skilled in the art. In that regard, the distal ends 31, 32 of the gripping jaws 25, 26 are convergent, as viewed in FIG. 3, and include V-shaped notches N. The V-notches N are preferred in that they serve to wedgingly grip the manually rotatable adjustment portions of many hand tools. The converging relationship of the ends 31, 32 also aids in a tight grasping effect, as will be further explained. 
     In the disclosed embodiment, the flat portions 29 and 30 are intermediate and join angled webs 33, 34, respectively, of the gripping jaws 25, 26. The angled webs 33, 34 each define an angle A therebetween of from about 90° to 120° to aid in accommodating the various shapes of the adjustment mechanisms C-clamps, vise-grips, bench vises, etc. 
     The clamping arms 25, 26 are preferably rubber coated for additional tacky gripping contact with the tools to be rotated. 
     In the disclosed form of the invention, the clamp arms 17 and 18 are spring biased to urge the gripping jaws 25, 26 toward each other by means of a helical compression spring 35. The spring 35 is in compression and exerts outward force which moves lower opposing arm 36, 37, of the main clamp arms 17, 18, away from each other while at the same time urging the upper arms 21, 22 toward each other. The upper arms 21, 22 extending generally in the same direction, and generally parallel to, the lower arms 36, 37. This results because the lower arms 36, 37 curl toward each other and are joined at said hinge 19. It will be seen from FIG. 1 that the main clamp arm 17 terminates at its lower end in a housing 38. The housing 38 includes a generally transverse cylindrical portion 39 with a bore 40 therethrough. The bore 40 accommodates a pin extending therethrough and through a coaxial hub 43 at the lower end of the secondary clamp arm 18. Thereby, the clamp arms 17, 18 are relatively pivotal at pivot 19. The housing 38 further includes a vertical oriented tube 44 for receipt therein of a shaft 45. The shaft 45 is mechanically pinned to the tube 44 by a rivet 46 and extends downwardly therefrom. The shaft 45 carries a safety release mechanism in the form of ballbearings 47, 48 which are outwardly biased by spring 49, 50, respectively. The ballbearings 47, 48 are preferably arranged on the shaft 45 generally at 180° spacing and define an outside diameter of approximately 0.275-0.300 inches, in the exemplary, embodiment for engagement in a hex drive socket of a cordless power drill having a standard 1/4 inch nominal size. Of course, other dimensions can be created for engagement with different size drive sockets, or the like. Thereby, the diameter of shaft 45, and outside diameter defined around the ballbearings 47, 48, can be varied. 
     The purpose of the shaft 45 is for it to be placed into the socket 16, for example, which, as noted, is preferably a hex drive socket for a power tool 15. The ballbearing function is to keep the shaft 45 snug in the hex drive socket 16, but when the limits of travel are reached for rotating the threaded shaft 12 relative to the clamp arm 13 of the C-clamp 11, the ballbearings 47, 48 will be forced against the springs 49, 50, respectively, and retract inwardly of the outer periphery of the shaft 45. The shaft 45 will then spin freely in the rotating hex drive socket 16 to prevent locking-up or freezing, which could result in damage to the motor of the power tool 15. 
     In the depicted embodiment, the helical spring 35 exerts in the range of 12-15 pounds of force to yield sufficient gripping pressure at the jaws 25, 26 for clamping and rotating most hand tools. 
     The accessory clamp 10 can be driven clockwise or counterclockwise without changing the grip on the pin 14. 
     It will be further appreciated that the tube 44 of the housing 38 can be formed with an open slot 51 whereby the housing 38 and clamp arm 17, and the hub 43 and clamp arm 18, need not be cast as unitary constructions. Thereby, the material for the clamping arms 17, 18 may be made of sheet or spring steel and the metal being cold formed into the shown configurations. 
     It will be understood by those skilled in the art that the invention is not limited to use with hexagonal shaped drive sockets of power tools, nor is the ballbearing arrangement, at 47, 48, limited to two locations. The numbers of ballbearings and the overload pressure characteristics of the springs 49 and 50 can be varied to make the shaft 45 to spin free when the tool engaged thereto has been tightened or loosened to its full travel. Of course, other known release means, such as wire springs, leaf springs, clutch-type devices, dry wall screwdrivers, and the like, may be used to release the shaft and prevent overload. 
     The foregoing has been a description of a preferred embodiment of the invention but a wider range of embodiments fall within the scope of the claims appended hereto.