Abstract:
An improved clamping assembly especially suited for use in a bench vise for allowing a user to choose between conventional fine-screw-reduction closure and/or opening of the jaws for clamping, or quick-set sliding adjustment of the jaws. The clamping assembly relies on a toothed rack and pawl. The pawl is selectively engaged with the toothed rack to allow conventional reduction gear closure or opening. Alternatively, a user can more quickly open and close the jaws by disengaging the pawl from the rack and simply sliding the jaws relative to one another. The clamping assembly provides a quick-set clamping action which allows a user to initially to preset the jaws by sliding them together in one quick motion, followed by conventional fine-screw-adjustment for high-force clamping.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     The present application derives priority from U.S. Provisional Application Serial No. 60/361,507 filed Mar. 5, 2002. 
    
    
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to quick-set clamping mechanisms, and in particular, to an improved vise assembly which allows a user to initially to preset the jaws by sliding them together in one quick motion to save time, followed by conventional fine-screw-adjustment for clamping. 
     2. Description of the Background 
     The bench vice is an age-old tool for clamping and holding a work piece. A conventional bench vise, as shown in FIG. 1, includes a sliding jaw  12  mounted on a screw-spindle that is turned by a handle  10 . The other end of the screw-spindle is pivotally anchored in a housing  18  that sits on a base  16 . A stationary jaw  14  is integrally attached to the housing  18 . Manually turning handle  10  moves the sliding jaw  12  toward or away from housing  18 , respectively clamping or unclamping a workpiece. Although the utility and convenience of the traditional bench vise is beyond question, there is ample room for improvement. For example, if a user works on a large workpiece followed by a small one, he or she must adjust the jaws of the vice by screw-action from a wide-open position to a substantially closed one. This requires a great deal of turning effort and time. 
     It would be far more convenient to provide a quick-set mechanism to allow rapid opening and/or closing of the gap between the jaws. For example, when the gap between the jaws is at its largest and the user wants to clamp a small workpiece, it would be helpful to have the ability to slide the jaws together in one quick motion and thereby eliminate the need for a long hand cranking operation on the screw-spindle. On the other hand, a quick-setting adjustment capability as described would still need to work in conjunction with a conventional screw-clamping mechanism to give the user a reduction drive to exert a sufficient clamping force on the work piece without causing the two clamping mechanisms to bind up. 
     There have been a few prior efforts to develop clamping mechanisms that slide together. For example, U.S. Pat. No. 6,093,361 to Schad shows a clamp system in which a clamp piston  30  engages a rack  36  for reciprocating movement of a platen. Clamp piston  30  has teeth  34  that engage corresponding teeth  36  on column  24 . Rotation of clamp piston serves to engage or disengage clamp piston teeth  34  from column teeth  36 . However, this particular clamp design was intended for an injection molding machine, and the design is specifically adapted for this purpose. 
     It would be greatly advantageous to provide an improved clamping mechanism in the context of a bench vise which allows a user to rapidly open and/or close the gap between the jaws. This would allow the user to initially preset the jaws by sliding them together in one quick motion to save time, followed by conventional fine-screw-adjustment for reduction clamping. 
     SUMMARY OF THE INVENTION 
     It is, therefore, the primary object of the present invention to provide an improved quick-set clamping mechanism which allows a user to initially to preset the jaws by sliding them together in one quick motion, followed by conventional fine-screw-adjustment for high-force clamping. 
     It is another object to provide a vise with dual-adjustment mechanism which enables the jaws to be moved rapidly and in a single motion together, and which allows a separate clamping arrangement for moving the vise members relatively together a smaller distance to forcefully clamp the workpiece between the two jaws. 
     This object is achieved by providing a dual-action quick-set clamping mechanism, herein described in the context of a bench vise. The clamping mechanism includes a stationary jaw portion having a channel there through, and a toothed rack lining the channel. In addition, a slidable jaw portion includes a protruding hollow three-walled (top and two opposing side walls) beam that is inserted into the chamber of the stationary portion. A mandril having a threaded end is rotatably mounted within the hollow beam of the slidable portion. In addition, a toothed pawl having a threaded through-bore is mounted on the threaded end of the mandril. Thus, the mandril and pawl sit in the hollow of the beam of the slideable portion within the channel of said stationary jaw portion. The pawl has a bias spring for biasing the teeth of the pawl into engagement with the teeth of the rack. However, a user may quickly open or close the slidable jaw portion relative to the stationary portion by disengaging the pawl from the rack and sliding the beam of the slidable portion into (or out of) the channel of the stationary portion. Alternatively, the user may engage the pawl with the rack for screw-closing (or like opening) of the slidable portion against the stationary portion in a conventional bench-vise-like manner. This provides a quick-set clamping mechanism which allows a user to initially to preset the jaws by sliding them together in one quick motion, followed by conventional fine-screw-adjustment for high-force clamping. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     Other objects, features, and advantages of the present invention will become more apparent from the following detailed description of the preferred embodiment and certain modifications thereof when taken together with the accompanying drawings in which: 
     FIG. 1 is a perspective drawing of a conventional bench vise. 
     FIG. 2 is a perspective side drawing of a quick-set clamping mechanism incorporated in a bench vise according to one embodiment of the present invention. 
     FIG. 3 is a perspective end drawing of the quick-set clamping vise as in FIG.  2 . 
     FIG. 4 is a perspective drawing of the disassembled quick-set clamping vise as in FIGS. 2 and 3. 
     FIG. 5 is a perspective illustration of the mandril assembly of FIGS. 1-4 with spring-loaded toothed pawl  70  and toothed rack  60  extending within channel  40 . 
     FIG. 6 is a composite illustration of the various individual components of the vise. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     FIG. 2 is a perspective side drawing, and FIG. 3 is a perspective end drawing, respectively, of a quick-set clamping mechanism incorporated in a bench vise according to one embodiment of the present invention. 
     The vise generally includes a stationary housing  28  which may be anchored to a work surface, either stationary or by articulating pedestal (as shown), in a known manner as commonly employed by existing bench vices. The stationary housing  28  supports an integral jaw  30 . A slidable portion is inserted into the stationary housing, the slidable portion including a beam  26  integrally joined to a jaw  32  (jaw  32  opposing jaw  30 ). The clamping mechanism according to the present invention is incorporated in the foregoing components to allow a user to quickly open and/or close the jaws  30 ,  32 , and to initially preset the jaws  30 ,  32  by sliding jaw  32  together in one quick motion to save time, followed by conventional fine-screw-adjustment of a threaded mandril  23  using handle  22  for clamping a workpiece between jaws  30 ,  32 . 
     FIG. 4 is a perspective drawing of the disassembled quick-set clamping vise as in FIGS. 2-3 showing the primary components. The stationary housing  28  with integral jaw  30  may be machined or cast from an appropriate metal or other sturdy material, and includes a rectangular channel  40  for insertion of the beam  26  of the slidable portion. A toothed rack (not seen in FIG. 3) extends along the floor of channel  40 . 
     The beam  26  of the slidable portion is three-walled and has a rectilinear cross-section forming a hollow interior with opposing side walls ( 26   b  and  26   c ) and a top wall ( 26   a ), and is integrally connected to jaw  32  at a junction  31 . The junction  31  is likewise provided with a hollow interior contiguous with that of beam  26  and opening at an aperture to the right. A pair of bushings  50   a  &amp;  50   b  are clamped therein by respective set screws  56 . When tightened, set screws  56  constrict the walls of junction  31  around the bushings  50   a  &amp;  50   b . Bushings  50   a  &amp;  50   b  are annular (preferably brass or bronze) eyelet-type bushings with lateral through-bores for supporting a pivoting bearing  52  interiorly of the junction  31 . The bushings  50  pivotally suspend bearing  52  across the walls of junction  31 . The suspended bearing  52  rotatably captures the threaded mandril  23  therein. For this purpose, the bearing  52  is provided with a through-bore that conforms to a constricted collar  102  on mandril  23 . The constricted collar  102  is rotatably captured within the bearing  52 . This configuration allows the threaded barrel of mandril  23  to protrude down through the hollow beam  26  of slidable portion. A hub  34  is integrally formed at the other end of mandril  23 , the hub  34  protruding outward from junction  31  to allow manual turning via handle  22 . The handle  22  is inserted through a hole in the hub  34  as is well-known. 
     As seen in FIG. 4, an integral thumb-hold  21  protrudes outwardly from junction  31 . 
     The threaded barrel of mandril  23  protrudes to a spring-loaded toothed pawl  70  which resides inside beam  26  of the slidable portion within channel  40  and which cooperates with the toothed rack (not seen in FIG. 2 or  3 ) that extends within channel  40 . The pawl  70  is equipped with bias spring  72  that imparts a spring-bias against the ;underside of the top wall  26   a  of beam  26 , thereby maintaining the teeth of pawl  70  in engagement with the teeth of the rack  60 . A generally U-shaped jaw stop  53  is screw-attached to stationary housing  28  with prongs flanking the channel  40 . The prongs are spaced to fit up inside the hollow beam  26  of slidable portion and to allow free sliding, but they catch the pawl  70 , thereby limiting the outward extraction of the pawl  70  and beam  26  so that it does not fall out. 
     FIG. 5 is a perspective illustration of the man drill  23  assembly showing its cooperation with spring-loaded toothed pawl  70 , which in turn engages the toothed rack  60  that extends with channel  40  (not shown) in housing  28 . 
     The toothed rack  60  is an elongate section of hardened steel with upwardly disposed and forwardly oriented teeth. The pawl  70  is a generally square member of hardened steel formed with downwardly disposed and rearwardly oriented teeth, and a lateral through-bore with internal screw threads for cooperation with the threaded end of mandril  23 . The teeth of rack  60  oppose those of pawl  70  and, when engaged, prevent leftward movement (viewing FIG.  5 ). The bias spring  72  is a bent section of spring steel that is upwardly directed against the underside of the top wall  26   a  of beam  26  which is positioned against the roof of channel  40  and thereby biases the teeth of pawl  70  into engagement with the teeth of the rack  60  along the floor of channel  40 . 
     Bearing  52  is a collar with flanking pivot pins protruding therefrom. The pivot pins are held captive in the respective bushings  50   a  &amp;  50   b  in the walls of junction  31 . The mandril  23  passes through the bearing  52  and is rotatably seated therein. The threaded end of mandril  23  is journaled through pawl  70 , and rotation of mandril  23  moves pawl  70  back or forth there along. A C-clamp retaining ring  101  is inserted onto the tip of the threaded portion of mandril  23  to prevent the pawl  70  from becoming dislodged. 
     FIG. 6 is a composite illustration of the various individual components of the vise. 
     At position A, an exemplary one of the two bushings  50   a  &amp;  50   b  is shown to be an annular ferrule-type bushing with lateral through-bore and a raised lip on one side. 
     At position B, the pawl  70  is a generally square member of hardened steel formed with downwardly disposed and rearwardly oriented teeth. The pawl  70  is formed with a threaded interior through-bore  74 , and a lateral slot may be machined into the top of pawl  70  to anchor one leaf of bias spring  72 . 
     At position C, the entire length of mandril  23  is shown. Mandril  23  is threaded along a distal end for screw-insertion of pawl  70  thereon. Pawl  70  rides along the threaded mandril  23 . The threads of mandril  23  end and its barrel continues to the larger-diameter hub  34  with radial through-bore  75  for insertion of handle  22 . Handle  22  allows convenient manual turning of the hub  34  and mandril  23  within the bearing  52 . 
     At position D, the rack  60  is an elongate section of hardened steel with upwardly disposed and forwardly oriented teeth. The rack may be formed with a T-shaped cross-section as shown to sit within a groove in stationary housing  28 . Spaced bore holes allow screw-attachment within housing  28 . 
     At positions E and F, respectively, two retaining rings are used. The first (shown at E) is retaining ring  101  used to keep pawl  70  from coming off of the threaded end of mandril  23 . The second (shown at F) is retaining ring  102  is inserted onto mandril  23  inside the bearing  52  to prevent mandril  23  from being withdrawn out of bearing  52 . 
     At position G, an exemplary bias spring  72  is shown. The bias spring  72  is a simple piece of angled spring steel that is anchored into the back of the pawl  70  in slot  73 . 
     At position H, an exemplary bearing  52  is shown. Bearing  52  is a annular member with through-bore and flanking pivot pins protruding on opposite sides. The mandril  23  passes through the bearing  52  and is rotatably seated therein. 
     At position I, a jaw stop  53  is shown. The jaw stop  53  is a U-shaped plate that is screw attached as shown in FIG. 4, prongs-up inside the beam  26  of the slidable portion. Jaw stop  53  serves to limit the outward extraction of the slidable portion so that it does not fall out. 
     At position J, an optional pawl stop  54  is shown. The pawl stop  54  is an alternative to the retaining ring  101 , and is a simple threaded screw inserted into a threaded bore in the tip of the mandril  23 . As with retaining ring  101 , the head of pawl stop  54  extends radially outward from the threaded portion of mandril  23  and serves to limit the lateral motion of pawl  70 , thereby ensuring that pawl  70  cannot fall off the threaded portion of mandril  23 . 
     In operation of the above-described embodiment, the mechanism enables dual-adjustment. Beginning from a fully open position in which the jaws  30  and  32  are widespread, the user can make a course adjustment in which the jaws are moved rapidly and in a single motion together to enclose a workpiece. This is accomplished by squeezing (or lifting) the integral thumb-hold  21  and handle-end of mandril  23  (hub  34 ) between the thumb and forefinger. This action pivots the mandril  23  within pivoting bearing  52  about the bushings  50  interiorly of the junction  31 . The threaded end  24  of mandril  23  pivots upwardly. The pawl  70 , which is threadably inserted on the end of mandril  23 , is lifted off of the toothed rack  60  (against the bias of spring  72 ). With pawl  70  disengaged, the jaw  32  can be shoved manually toward jaw  30  and the beam  26  of the slidable portion is free to telescope through the hollow interior of channel  40  (and outward through the aperture to the right, if necessary). When the jaws  30  and  32  are properly positioned, the thumb-hold  21  and the handle end of the mandril  23  (hub  34 ) are released and the pawl  70  snaps back down into engagement with rack  60 . 
     With pawl  70  and rack  60  engaged, clockwise turning of handle  22  turns mandril  23 , which serves as a conventional reduction drive to retract the toothed pawl  70 , thereby closing and clamping the jaws  32 ,  34  on the work piece with proper screw-force. The pawl  70  resides inside the slidable beam  26  which in turn is slidably inserted into channel  40 , and the bias spring maintains it in a normally-engaged position with the teeth of the rack  60  for reduction drive. 
     The foregoing configuration provides a quick-set clamping mechanism which allows a user to initially to preset the jaws  32 ,  34  by sliding them together in one quick motion, followed by conventional fine-screw-adjustment for high-force clamping. 
     Simply reversing the above-described action allows the user to open the jaws  32 ,  34  by the same sliding and/or screw motion. 
     Having now fully set forth the preferred embodiments and certain modifications of the concept underlying the present invention, various other embodiments as well as certain variations and modifications of the embodiments herein shown and described will obviously occur to those skilled in the art upon becoming familiar with said underlying concept. It is to be understood, therefore, that the invention may be practiced otherwise than as specifically set forth in the appended claims.