Patent Publication Number: US-7222842-B2

Title: Vise clamp

Description:
BACKGROUND OF INVENTION 
   1. Field of Invention 
   The present invention relates to a vise clamp 
   2. Related Prior Art 
   A vise clamp is primarily used in places where a vise cannot be used. For example, in processing planks, a vise clamp can be moved to various positions as desired by a user, but a vise cannot. A C-shaped vise clamp includes a body, a stationary jaw formed on the body, a screw installed on the body, and a movable jaw with a screw hole for receiving the screw. By means of rotating the screw, the movable jaw is moved up and down in order to clamp. For not including a retaining device, the C-shaped vise clamp often looses when subject to vibration. The following steps of the operation are thus affected. Moreover, the movable jaw can only be moved by means of rotating the screw, the speed of clamping is slowed. The smoothness of the operation is affected. 
   There has been devised a new C-shaped vise clamp including a stationary jaw, a movable jaw installed on the stationary jaw, and a clamping device connected to the movable jaw. The clamping device includes a lever formed with a cam. A ratchet mechanism is provided between the lever and the movable jaw. A contact element is put against the cam. Wishing to clamp a workpiece, a user moves the movable jaw so that the movable jaw reaches the workpiece. The user pivots the lever. The cam pushes the contact element. Thus, vise clamp clamps the workpiece. The ratchet mechanism is supposed to retain the lever and therefore the contact element in position. The pivotal of the lever is faster than the rotation of a screw. 
   In the foregoing C-shaped vise clamp, the cam formed on the lever is used to clamp; however, it causes an inadequate stroke of the movement of the contact element and therefore an adequate clamping force. The clamping force is particularly inadequate when it is used to clamp an elastic workpiece. Moreover, the abutment of the cam against the contact element affects the position of the contact element so that the contact element may not fully contact a workpiece. Hence, the clamping is not stable. Hence, there is room for improvements. 
   The present invention is therefore intended to obviate or at least alleviate the problems encountered in prior art. 
   SUMMARY OF INVENTION 
   The primary objective of the present invention is to provide a vise clamp that can provide a large clamping force and be operated stably. 
   According to the present invention, a vise clamp includes a stationary jaw and a movable jaw put on the stationary jaw. The movable jaw includes an ear formed with ratchets. A lever is formed with two ears connected to the ear of the movable jaw. A pawl is connected to the lever and formed with ratchets for engagement with the ratchets of the movable jaw. Two pinions are connected to the ears of the lever. Two pushers sandwich the pinions, and each includes a slot defined therein and a rack engaged with one of the pinions so that the pushers are moved as the pinions are rotated. A contact element is put against the pushers so that the former can be pushed by means of the latter. The contact element includes two ears sandwiching the pushers. Each of the ears of the contact element defines a slot. A shaft is driven through the ear of the movable jaw, the ears of the lever and the pinions so that they are rotated together with one another. The slots of the pushers and the slots of the contact element receive the shaft in order to allow movement of the pushers and the contact element relative to the shaft. 
   Other advantages and novel features of the invention will become more apparent from the following detailed description in conjunction with the drawings. 

   
     BRIEF DESCRIPTION OF DRAWINGS 
     The present invention will be described through detailed illustration of the preferred embodiment referring to the drawings. 
       FIG. 1  is a perspective view of a vise clamp according to the preferred embodiment of the present invention. 
       FIG. 2  is an exploded view of the vise clamp shown in  FIG. 1 . 
       FIG. 3  is a side view of the vise clamp shown in  FIG. 1 . 
       FIG. 4  is a cross-sectional partial view of the vise clamp of  FIG. 3 . 
       FIG. 5  is another cross-sectional partial view of the vise clamp shown in  FIG. 3 . 
       FIG. 6  is a side view of a workpiece clamped by means of the vise clamp shown in  FIG. 3 . 
   

   DETAILED DESCRIPTION OF PREFERRED EMBODIMENT 
   Referring to  FIGS. 1 and 2 , there is shown a vise clamp according to the preferred embodiment. The vise clamp includes a stationary jaw  10 , a movable jaw  20  and a clamping device  30 . The stationary jaw  10  is inverted L-shaped, i.e., including a first section and a second section perpendicular to the first section. A contact portion  15  is formed on the first section of the stationary jaw  10 . In a sliding manner, the second section of the stationary jaw  10  is inserted through an aperture  21  defined in the movable jaw  20 . The clamping device  30  is connected to the movable jaw  20 . The clamping device  30  includes a contact element  37  controlled by means of a lever  31 . 
   The movable jaw  20  includes, at an end, an ear  25  to which the clamping device  30  is connected. The ear  25  includes an aperture  26  defined therein and a series of ratchets  27  formed along the periphery of the ear  25 . The lever  31  includes, at an end, two ears  32  corresponding to the ear  25  of the movable jaw  20 . Each ear  32  defines a non-circular aperture  320 . A shaft  33  includes two non-circular ends  34  compliant to the non-circular apertures  320 . The shaft  33  is inserted through the aperture  26 . The non-circular ends  34  of the shaft  33  are fit in the non-circular apertures  320  of the lever  31 . Thus, the lever  31  is connected to the movable jaw  20 , and the shaft  33  will be rotated together with the lever  31 . Each non-circular end  34  of the shaft  33  is fit in a non-circular aperture  350  defined in a pinion  35 . Teeth  351  are formed along the periphery of each pinion  35 . 
   The clamping device  30  includes two pushers  36  provided beyond the pinions  35 . Each pusher  36  includes a slot  360  defined therein, a space  361  communicated with the slot  360  and a rack  362  formed on the wall of the space  361 . The racks  362  are engaged with the pinions  35  so that the pushers  36  are moved as the pinions  35  are rotated. The contact element  37  includes two ears  370  formed on two sides and located beyond the pushers  36 . Each ear  370  defines a slot  371  for receiving the shaft  33 . Thus, the contact element  37  can be moved by means of the pushers  36 . A pawl  38  is pivotally connected to the lever  31  by means of a pin  39 . A spring  380  is put between the pawl  38  and the lever  31 . The pawl  38  includes, at an end, ratchets  381  for engagement with the ratchets  27  of the ear  25 . Thus, after pivoted, the lever  31  is retained in position by means of the pawl  38 . 
   As discussed above, the vise clamp according to the present invention can provide a large clamping force and be operated stably. 
   Referring to  FIGS. 3 through 6 , the operation of the vise clamp will be described. Wishing to clamp a workpiece, a user put the workpiece between the contact portion  15  of the stationary jaw  10  and the contact element  37  connected to the movable jaw  20 . The user moves the movable jaw  20  up so that the contact element  37  contacts the workpiece. The user pivots the lever  31  and therefore the shaft  33 . The shaft  33  pivots the pinions  35 . By means of the engagement of the pinions  35  with the racks  362 , the pinions  35  move the pushers  36  up. In turn, the pushers  36  push the contact element  37  up. Simultaneously, the movable jaw  20  is tilted in order to hold on to the stationary jaw  10 . The contact element  37  continues to move up so that its top fully contacts the bottom of the workpiece. The contact element  37  continues to move up so that the vise clamp tightly clamps the workpiece. The clamping force is large. The operation is stable. Because the second section of the stationary jaw  10  is long, the range of thicknesses of workpieces that can be clamped by means of the vise clamp is large. 
   The present invention has been described through the detailed illustration of the preferred embodiment. Those skilled in the art can derive variations from the preferred embodiment without departing from the scope of the present invention. Therefore, the preferred embodiment shall not limit the scope of the present invention defined in the claims.