Abstract:
A method and apparatus for clamping a work piece is disclosed. The apparatus generally includes a stationary jaw with a first clamping surface and a moveable jaw with a second clamping surface connected and operated by a spindle. The spindle moves the stationary jaw and moveable jaw toward each other when rotated in one direction. The spindle disengages the stationary jaw when rotated in the opposite direction, thus allowing for rapid adjustment of the apparatus.

Description:
BACKGROUND OF THE INVENTION 
   1. Field of the Invention 
   Embodiments of the present invention generally relate to a hand tool and more particularly to a vise. More particularly still, embodiments of the invention relate to a table top mounted vise with improved performance and utility. 
   2. Description of the Related Art 
   Vises are used in order to temporarily hold one or more objects so that work can be performed on them. Traditional table top mounted vises have existed for years. A typical vise is composed of a stationary jaw with a base that can be mounted to a surface. There is a moveable jaw and a guide rod(s) that allows the moveable jaw to move smoothly toward and away from the stationary jaw. Each jaw has a clamping surface for holding a work piece. Further, the vise has a screw and lever system which operates the moveable jaw. The screw typically has a relatively fine pitched thread which provides a large mechanical advantage such that a relatively small amount of torque applied to the lever produces a large clamping force between the jaws. The screw moves the moveable jaw whereby the fine pitch required for the large mechanical advantage causes the jaw to move a very small distance with each turn. Thus, adjusting the jaws to different opening sizes for clamping of relatively thin and subsequently relatively thick items (or vice versa) requires numerous turns of the lever attached to the screw. 
   Recent developments in vises have allowed for a quicker adjustment of the vise. The vise designs have generated solutions that allow the fine pitched thread mechanism to be disengaged while allowing rough adjustments of the vise head. Where the traditional vise had a female thread integral to the stationary jaw that engaged with the screw, these new vises have a female thread part separate from the stationary jaw. The separate part is called a semi-thread because it engages with less than 180° of the screw. The semi-thread rides in a track system in the stationary head such that a mechanism can disengage the semi-thread from the screw as desired. With the semi-thread disengaged, a user can slide the moveable jaw to the approximate opening size required for application at hand. A separate lever on the moveable jaw turns a bar or shaft that subsequently disengages the semi-thread from the male thread. The semi-thread is typically spring loaded into engagement with the male thread. With the semi-thread disengaged the jaw opening can be adjusted to the desired size. This system is a vast improvement over previous vises, increasing the efficiency of use. 
   However, there are several problems with the prior art. The prior art requires two levers to operate. One lever is required to turn the bar and subsequently disengage the semi-thread. While holding this lever in position to keep the semi-thread out of engagement, the jaw opening can be adjusted to the appropriate size by pulling or pushing on the moveable jaw. To apply large clamping force the user must let go of this first lever and grab the second lever that turns the screw to apply a significant clamping force. 
   Therefore, a need exists for an improved apparatus and method of vise clamping that would allow a user to quickly adjust the opening size of the jaws and apply clamping force to the jaw through the use of one lever. 
   SUMMARY OF THE INVENTION 
   The present invention generally relates to a method and apparatus for clamping a work piece. The apparatus generally includes a stationary jaw with a first clamping surface and a moveable jaw with a second clamping surface connected and operated by a spindle. The spindle moves the stationary jaw and moveable jaw toward each other when rotated in one direction. The spindle disengages the stationary jaw when rotated in the opposite direction, thus allowing for rapid adjustment of the apparatus. 
   According to one aspect of the invention, a clamping apparatus, includes a fixed jaw having a first clamping surface, a moveable jaw having a second clamping surface, and a spindle attached to both the fixed jaw and the moveable jaw for providing movement of the moveable jaw relative to the fixed jaw. The spindle is rotatable in a first direction to move the moveable jaw toward the fixed jaw and is rotatable in a second direction to disengage the fixed jaw from the spindle allowing rough adjustment of the moveable jaw. A lever operates the spindle. According to another aspect of the invention, a clamping apparatus includes a base for attaching the apparatus to a surface, a fixed jaw having a first clamping surface, a moveable jaw having a second clamping surface, a spindle attached to the moveable jaw, the spindle having a cam which operates a semi-nut which engages a threaded portion of the spindle, wherein the semi-nut is attached to the fixed jaw, and one lever which operates the spindle. 
   According to another aspect of the invention, a method for clamping a work piece, includes rotating a spindle in a first direction, the spindle coupled to a moveable jaw and a fixed jaw, wherein rotation in the first direction causes the moveable jaw to move toward the fixed jaw, clamping a work piece between the moveable jaw and the fixed jaw, rotating the spindle in a second direction to disengage the spindle from the fixed jaw, adjusting the moveable jaw to a desired location while the spindle is disengaged from the fixed jaw, and rotating the spindle in the first direction in order to reengage the spindle with the fixed jaw. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
     So that the manner in which the above recited features of the present invention can be understood in detail, a more particular description of the invention, briefly summarized above, may be had by reference to embodiments, some of which are illustrated in the appended drawings. It is to be noted, however, that the appended drawings illustrate only typical embodiments of this invention and are therefore not to be considered limiting of its scope, for the invention may admit to other equally effective embodiments. 
       FIG. 1  is a perspective view of the vise in accordance with embodiments of the invention. 
       FIG. 2  is a cross sectional view of the vise. 
       FIG. 3  is a cross sectional view of a base insert and semi-nut. 
       FIG. 4  is a cross sectional end view of the base insert and semi-nut. 
       FIG. 5  is a cross sectional end view of the base insert and semi-nut. 
       FIG. 6  is a perspective view of a cam and spindle. 
       FIG. 7  is an end view of the cam. 
       FIG. 8  is a perspective view of the cam and spindle attached to a semi-lever and sheet bar. 
   

   DETAILED DESCRIPTION 
     FIG. 1  illustrates a perspective view of a vise  1  which is configured to incorporate embodiments of the present invention. The vise  1  includes a moveable jaw  10  which includes a clamping surface  15 . The moveable jaw  10  is attached to a channel  50  which is guided through an opening  60  of the housing of a fixed jaw  20 . The fixed jaw  20  is attached to a base  40  for mounting the vise  1  to a surface. The fixed jaw  20  includes a clamping surface  25 . A spindle  70  is attached to both the moveable jaw  10  and the fixed jaw  20  and projects from the moveable jaw  10  at opening  65 . The spindle  70  is attached to a lever  30 . The lever  30  moves the moveable jaw  10  toward the fixed jaw  20  when rotated in one direction. The lever  30  releases the fixed jaw  20  from the spindle  70  when rotated in the opposite direction, thus allowing free movement of the moveable jaw  10  (described further below). 
     FIG. 2  shows a schematic cross sectional view of the vise  1 . The figure depicts the spindle  70  going through the moveable jaw  10  and mechanically engaging the fixed jaw  20  as described below. The spindle  70  attaches to the moveable jaw  10  at opening  65  such that the spindle  70  is free to rotate about axis X—X, but not allowed to move in any other direction. The spindle  70  leaves the moveable jaw  10  through opening  66  and is now inside the channel  50 . Near opening  66  the spindle  70  is immovably attached to a cam  130 . The cam  130  operates semi-lever  300  which moves a sheet bar  120 . The sheet bar  120  moves semi-nut  110  into or out of engagement with a threaded potion  80  of the spindle  70 . 
   The semi-nut  110  rests in aperture  95  of base insert  90  such that the semi-nut  110  moves only toward and away from the spindle  70 . At the opposite end of the semi-nut from the spindle  70 , a spring  100  attaches to the semi-nut  110 . The spring  100  forces the semi-nut  110  into engagement with the threaded portion  80  of the spindle  70 . The base insert  90  is immovably attached to the base  40  of the vise  1 . As the spindle  70  rotates with the semi-nut  110  engaged, the threaded portion  80  moves the moveable jaw  10  toward or away from the fixed jaw  20 . 
     FIG. 3  depicts a cross sectional view of the base insert  90 . The figure depicts a more detailed view of the surface of the semi-nut  110  which engages the threaded portion  80  of the spindle  70 . The semi-nut  110  contains threaded grooves  115  which engage with the threaded portion  80  of the spindle  70  in order to move the moveable jaw  10 . The base inset  90  and the semi-nut  110  are curved at the top to correspond with the spindle  70 . 
     FIGS. 4 and 5  depict a cross sectional side view of the base insert  90 . The figures show a groove  125  in the semi-nut  110 , which is adapted to receive the sheet bar  120 .  FIG. 4  shows the semi-nut  110  engaged with the spindle  70 . With the semi-nut  110  engaged with the spindle, sheet bar  120  rests in a recess  114  in the base insert  90  and does not exert force on the semi-nut  110 . As the sheet bar  120  moves, it pushes the semi-nut  110  down causing the spring  100  to compress, as shown in  FIG. 5 . As the spring  100  compresses, the semi-nut  110  disengages the threaded portion  80  of the spindle  70 . With the semi-nut  110  disengaged, the moveable jaw  10  is free to move toward or away from the fixed jaw  20 . 
     FIG. 6  is a perspective view of the cam  130 . The cam  130  is a stepped cylindrical part with a central hole through which spindle  70  projects. The cam  130  includes a series of shaped channels  210 ,  220  and  230  on the face of cam  130 . The cam  130  further includes one or more sheet springs  200 . One end of the one or more sheet springs  200  attach to the cam  130  in slots  215 . The other end of the one or more sheet springs  200  is in contact with spindle  70 . As shown the two or more sheet springs  200  help define the series of shaped channels  210 ,  220  and  230 . 
     FIG. 7  is an end view of the face of the cam  130  showing the cam  130  in engagement with the semi-lever  300 . The semi-lever  300  includes a pin  320  which is guided by the cam  130  in the series of channels  210 ,  220  and  230 . The semi-lever attaches to a spring  310  which forces the pin  320  toward the spindle  70 . As the cam  130  rotates in a clockwise direction, the pin  320  remains in the interior channel  210  which is the channel closest to the spindle  70 . The pin  320  lifts the sheet spring  200  as the pin  320  moves around the spindle  70 . As the cam  130  rotates in a counter-clockwise direction, the pin  320  moves away from the spindle  70 . The counter-clockwise rotation moves the pin  320  onto the sheet spring  200  and into the channel  220  formed in the middle of the cam  130  and finally to the channel  230  disposed along the outside of the cam  130 . 
   The semi-lever  300  includes a pivot  340 , a pin end  330  and a shaft end  350 . The shaft end  350  attaches to shaft  360  which attaches to the sheet bar  120 . As the pin  320  moves away from the spindle  70 , the semi-lever  300  rotates about pivot  340 . As the semi-lever  300  rotates, the shaft  360  moves with the shaft end  350 . As the shaft  360  moves, the sheet bar  120  is rotated so that the semi-nut  110  becomes disengaged from the threaded portion  80  of the spindle  70 . 
     FIG. 8  is a perspective view of the cam  130  with the semi-lever  300  and the sheet bar  120  attached. When the spindle  70  moves in a first direction the pin  320  remains next to the spindle  70 . With the pin  320  next to the spindle  70 , the semi-nut  110  is in engagement with the threaded portion  80  of the spindle  70  because the sheet bar  120  is not acting on the semi-nut  110 . Thus, continued rotation in the first direction causes the moveable jaw  10  to move toward the fixed jaw  20  allowing for clamping of a work piece. As the spindle  70  rotates in a second direction, the semi-lever  300  moves the sheet bar  120  so that the semi-nut  110  disengages the threaded portion  80  of the spindle  70 . Once disengaged, the semi-nut  110  remains disengaged until the spindle  70  is rotated in the first direction. While the semi-nut  110  is disengaged, a user is able to move the moveable jaw  10  toward and away from the fixed jaw  20  as desired in accordance with the size of the work piece. Once the moveable jaw  10  is in the desired location, the user rotates the spindle  70  in the first direction which moves the pin  320  toward the spindle and in turn the sheet bar  120  rotates to enable the semi-nut  110  to reengage the threaded portion  80  of the spindle. Continued rotation of the spindle  70  in the first direction moves the moveable jaw  10  toward the fixed jaw  20  in order to clamp the work piece. 
   While the foregoing is directed to embodiments of the present invention, other and further embodiments of the invention may be devised without departing from the basic scope thereof, and the scope thereof is determined by the claims that follow.