Abstract:
The present invention relates to a miter box. Miter boxes have a base, a pair of opposed side walls, and at least one aligned slot in the side walls. An embodiment of the present invention includes at least one guide rail mounted on the base perpendicular to the side wall. Further, a clamping assembly is positioned on the guide rail. The clamping assembly is selectively moveable along said guide rail. In this manner, a work piece can be secured to the miter box to hold the piece in position while it is being cut.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     The present application claims priority under 35 USC §119 to Chinese application 200820057550.7 filed Apr. 22, 2008, which is incorporated herein by reference. 
     BACKGROUND 
     Miter boxes have been in use for many years. Miter boxes are used for cutting pieces of wood at a pre-determined angle. The miter box has aligned slots in the side walls to allow the user to position the saw. The slots prevent the saw from moving or shifting away from position. When using the miter box the user must use one hand to hold the work piece and the miter box while using the other hand to cut. As a result often the work piece will move or the miter box will slide across the table. Attempts to solve this problem have resulted in miter boxes that are expensive to manufacture and complicated to use. 
     SUMMARY OF THE INVENTION 
     The present invention relates to a miter box. Miter boxes have a base, a pair of opposed side walls, and at least one aligned slot in the side walls. An embodiment of the present invention includes at least one guide rail mounted on said base perpendicular to the side wall. Further, a clamping assembly is positioned on the guide rail. The clamping assembly is selectively moveable along the guide rail. In this manner, a work piece can be secured to the miter box to hold the piece in position while it is being cut. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a perspective view, party exploded, of an embodiment of the invention. 
         FIG. 2  is an exploded view of an embodiment of the clamping and locking assembly. 
         FIG. 3  is a perspective view of an embodiment of the c-clamp that may be used to hold the miter box. 
     
    
    
     DETAILED DESCRIPTION 
     Referring to  FIG. 1  is an illustration of an embodiment of the invention. The miter box  10  comprises an elongated base  1   c  with opposed side walls  1   a  and  1   b . The miter box has at least one and preferably six aligned slots  1   d  cut into each side wall so that a saw is guided into position and held in the position while cutting. This allows the user to quickly and accurately cut angles including 90, 45, and 22.5 degrees. The top face of side walls  1   a  and  1   b  may have measurement marks which also aide the user in measuring the work piece for cutting. 
     In an embodiment, the miter box may also have one or more bracing legs  11  in alignment on the under side of the miter box  10 . Miter box  10  is formed to have a receptacle for pivot pin  111 . Pivot pin  1111  attaches the leg  11  to miter box  10 . This allows the user to pivot the legs  11  down and place the miter box  10  against the end of a table. The legs  11  brace miter box  10  against the table preventing the miter box  10  from sliding forward when the user is cutting. In addition to bracing legs  11 , an embodiment may also have foot pads  12  on each corner of miter box  10 . The foot pads  12  provide friction to allow the miter box  10  to be placed on a smooth surface. 
     An embodiment may also include one or preferably two surfaces  13  adapted to receive c-clamp  14 . The surface provides a location to place the fixed end of the c-clamp  14 . In an embodiment, the surface  13  is rounded to receive a c-clamp  14  with a rounded fixed end  15 . This allows the user to place the fixed end  15  of the c-clamp  14  on the miter box  10  and clamp the adjustable end  17  of the c-clamp  14  to the underside of a table. This arrangement prevents the miter box  10  from sliding while the user is cutting. While, an embodiment may include a rounded surface  13 , it should be understood that an alternate embodiment may provide a flat surface for a c-clamp  14  with a flat fixed end surface to rest. 
     In an embodiment, the elongated base  1   c  may also include one or preferably two channels  311  formed in the base  1   c . The channels  311  are at opposite ends and extend the length of the base  1   c . In an embodiment the channels extend through the thickness of base  1   c.    
     Each channel  311  is adapted to receive a guide rail  31 . Guide rail  31  is a rectangular rail that fits inside the channel  311  and has a clasp  33  that engages in an opening  35  at one end of the side wall  1   a  to secure the rail  31  to the miter box  10 . The end  37  of the rail  31  opposite the clasp  33  is engaged in an opening  39  at the lower end of the side wall  1   b  to further secure rail  31  to the miter box. The rail  31  is removable so the user can clean the miter box  10 . It should be understood that the guide rails do not necessarily need to be placed in the channels. The guide rails may be mounted on the top surface of elongated base  1   c.    
     The guide rail  31  provides a track for clamping assembly  20  to traverse. The clamping assembly  20  is selectively positioned along the track depending on the size of the work piece. In an embodiment, the clamping assembly  20  included a main body  2  having an opening  21  through which the guide rail extends so that the user can slide the clamping assembly  20  to abut the work piece. This is considered the course adjustment. 
     The course adjustment  3  includes a gear rack  32  that is seated in and forms a part of the guide rail  31 . Ratchet  5  has gears  51  on the underside which mesh with notches  321  on gear rack  32 . In this arrangement, the clamp assembly  20  forward traverses along the rack  32  with minimal external force. When motion stops, ratchet  5  is urged into its meshing position by spring  9 . Backward traverse is not possible without disengaging ratchet  5  because of the angle at which the notches  321  on the rack  32  are made. 
     The locking assembly of an embodiment includes a release  7  that includes a pair of arms  72   a  and  72   b  that extend to opposite sides of the main body  2  and are moveably secured to the main body  2  to disengage ratchet  5 . The user causes upward motion on release  7  which raises ratchet  5  upward disengaging mating gears  51  from gear rack  32 . This allows the user to slide the clamping assembly  20  backward, away from the work piece. Ratchet  5  is fixed to release  7  by screw  8  that extends through opening  71  in release  7  into an opening  23  in the main body  2 . When upward motion is applied to release  7 , by grasping the pair of arms  72   a  and  72   b , spring  9  is depressed by the screw&#39;s  8  movement within opening  23 . When release  7  is released, spring  9  urges ratchet  5  into rest position mating gears  51  with gear track  32 . 
     In an embodiment the clamping assembly  20  may include a fine adjustment. Fine adjustment includes a screw  4  engaged in hole  22  in main body  2  which presses upon plate  6 . Plate  6  has spaced-apart panels  19  slidable in slots  25  in the main body  2 . As screw  4  is turned by handle  41  clockwise the screw traverses out of hole  22  and engages plate  6  pushing plate  6  outward. Pressure against the plate  6  is relieved by turning screw  4  counter-clockwise. 
     The course and fine adjustment cooperate by allowing the user to push clamp assembly  20  forward along the gear rack  32  up against a work piece. The user may then engage the fine adjustment by turning screw  4  to move plate  6  causing more pressing force against the work piece which further prevents the work piece from moving. When the user is finished cutting, the user releases pressure by turning screw  4  counter-clock wise and then disengaging ratchet  5  and sliding assembly  20  backward. 
     Having thus described the invention in connection with the preferred embodiments thereof, it will be evident to those skilled in the art that various revisions can be made to the preferred embodiments described herein with out departing from the spirit and scope of the invention. It is my intention, however, that all such revisions and modifications that are evident to those skilled in the art will be included with in the scope of the following claims.