Abstract:
A vise jaw provides improved workpiece holding capabilities. The vise jaw utilizes a series of gripping pads located laterally along the jaw. When tightened by the vise, the gripping pads on the jaw introduce a horizontal force on the workpiece, causing them to penetrate and gouge the workpiece. The vise jaw is thereby designed to provide increased retention capabilities against a precision supporting surface. The workpiece will remain in place during the machining process regardless of the shape of the workpiece or the direction of the machine tool operation force.

Description:
CROSS REFERENCE TO RELATED APPLICATIONS  
       [0001]    This application claims the benefit of U.S. Provisional Application Ser. No. 60/248,818, filed Nov. 14, 2000, entitled “Jaw Assembly For Use In A Machine Tool Vise”, which is hereby incorporated by reference. 
     
    
     
       BACKGROUND OF THE INVENTION  
         [0002]    1. Field of the Invention  
           [0003]    The present invention relates generally to machine tools, and more particularly to an apparatus and method for setting up and securing a workpiece to a machine tool while performing various tooling operations thereon, such as boring, shaving, grinding, drilling and the like.  
           [0004]    2. Description of the Related Art  
           [0005]    The manufacturing industry requires many mechanical operations be performed on a single workpiece by a machine tool in order to develop the workpiece into a finished part. A workpiece must often be molded, cut, drilled, and ground to precise finished tolerances according to a specification. Machine tool operations require that the workpiece be positioned in a precise and secure manner, disposed horizontally, vertically or angularly, to a machine tool base for subsequent machining.  
           [0006]    It is well known in machining operations to support a workpiece in a vise or other part holder. Various designs of vises and vise jaws are used for this purpose. The workpiece might be secured by way of hard jaws, usually made of flat heat-treated steel, with parallels. Alternatively, the workpiece might be held in place using soft jaws, usually made of aluminum, which include a milled step. The workpiece can be secured tightly between the parallels of the vise, or can be placed on the flat step of the jaws and tightened in place for precision machining.  
           [0007]    However, using standard hard jaws with parallels and soft jaws with steps have proven ineffective in many cases. For example, in the case of a machining operation where the machine tool exerts a force transverse to the clamping force of the vise jaws, the workpiece will tend to shift or change its position relative to the machine tool. This can also occur where the workpiece extends substantially above the horizontal plane of the vise jaws and the machining operation is applied in a direction that is parallel to the clamping force of the jaws, thereby exerting a cantilevered force on the workpiece. The torque thus applied to the workpiece by the machine tool will likewise cause unwanted shifting or movement of the workpiece. This makes it difficult, if not impossible, to maintain rigid manufacturing tolerances on certain parts.  
           [0008]    For all of the foregoing reasons, an apparatus and method are needed in the manufacturing industry to provide an effective means to secure a workpiece to a machine tool vise to prevent movement or shifting of the workpiece relative to the machine no matter what operational forces are applied.  
         SUMMARY OF THE INVENTION  
         [0009]    The vise jaw of the present invention provides an improved workpiece holding assembly. The vise jaw utilizes a series of gripping pads located along the long edge of the jaw. When tightened by the vise, the gripping pads on the jaw introduce a horizontal force on the workpiece. Because the material from which the gripping pad is made is harder than that of the workpiece, the gripping pads will penetrate and gouge the workpiece as the horizontal force on the workpiece from the vise increases. The vise jaw is thereby designed to provide increased retention capabilities against a precision supporting surface. The workpiece will remain in place during the machining process regardless of the shape of the workpiece or the direction of the machine tool operational force. The vise jaw can be designed with varying step heights that can be adjusted to accommodate workpieces of varying dimensions.  
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0010]    [0010]FIG. 1 shows a side elevation view of a vise jaw assembly coupled to a machine tool vise in accordance with the principles of the present invention.  
         [0011]    [0011]FIG. 2 shows a side cross sectional view of a vise jaw of the present invention.  
         [0012]    [0012]FIG. 3 shows a top plan view of the vise jaw of the present invention.  
         [0013]    [0013]FIG. 4 shows a front elevation view of the vise jaw of the present invention.  
         [0014]    [0014]FIG. 5 shows a detailed front view of gripping pads and notches of the present invention.  
         [0015]    [0015]FIG. 6 shows the use of the vise jaw assembly on a workpiece according to the principles of the present invention.  
     
    
     DETAILED DESCRIPTION OF THE INVENTION  
       [0016]    [0016]FIG. 1 depicts a schematic of a side elevation view of one aspect of a vise assembly  100  of the present invention. As can be seen, the vise assembly  100  consists of a pair of matching vise jaws  110 . The vise jaws  110  of the vise assembly  100  are placed on a standard machine tool vise  115 . Each vise jaw  110  contains a means to couple the vise jaw to the machine tool vise  115 . In one aspect of the invention, each vise jaw  110  contains one or more attachment openings  140 , through which standard clamping or bolting means are used to secure the vise jaws  110  to the machine tool vise  115 . Once securely coupled to the machine tool vise  115  in this way, the vise jaws  110  are parallel and opposite to each other in the machine tool vise.  
         [0017]    [0017]FIG. 2 shows a detailed side elevation view of a cross section of the vise jaw  110 . As can be seen, the vise jaw  110  contains one or more attachment openings  140  discussed above in reference to FIG. 1. The cross section of vise jaw  110  is preferably L-shaped and comprises a plurality of gripping pads  210 , which are disposed laterally along the length of the vise jaw (discussed in more detail below with respect to FIG. 3). The vise jaw  110  also includes a vertical clamping surface  225  and a contact surface  220 . In one aspect of the invention, the contact surface  220  of the vise jaw  110  is a flat, milled surface that runs the length of the vise jaw (discussed in more detail below with respect to FIG. 3). The distance between the contact surface  220  and the bottom of the vise jaw  110  is shown as a step height  230 . In manufacturing the vise jaw  110 , the step height  230  is adjusted to accommodate workpieces of varying dimensions. For example, a workpiece with a relatively large vertical dimension would require a smaller step height  230 , while a workpiece with a relatively shorter vertical dimension would require a larger step height  230 . The gripping pad  210  protrudes horizontally and is perpendicular to the contact surface  220 . The cross section of the gripping pad  210  is characterized by a relief cut  240  on the bottom of the gripping pad and a chamfered surface  230  at the top of the gripping pad. As discussed above with reference to FIG. 1, a pair of vise jaws  110  is used to form the vise assembly  100 ; therefore, the vise jaw  110  shown and described in FIG. 2, depicted as a left side vise jaw, is a mirror image of and identical to the companion right side vise jaw of the vise assembly  100 .  
         [0018]    [0018]FIG. 3 depicts a top view of the vise jaw  110 . As discussed above with reference to FIG. 2, the vise jaw  110  comprises a plurality of gripping pads  210  disposed linearly along the length of the vise jaw at predetermined and regularly spaced intervals. Each gripping pad  210  is separated from each adjoining gripping pad by a notch  310 . Each notch  310  can be milled into the vise jaw  110  at various widths and intervals in order to accommodate workpieces of varying shapes, sizes and hardness. The contact surface  220  is preferably flat. The attachment opening  140  passes through the width of the vise jaw  110 .  
         [0019]    [0019]FIG. 4 shows a front elevation view of the vise jaw  110 . As discussed above with reference to FIGS. 2 and 3, the vise jaw  110  comprises a plurality of gripping pads  210  disposed linearly along the length of the vise jaw at predetermined and regularly spaced intervals. As can be seen, notches  310  separate each gripping pad  210 , and the attachment openings  140  are present to couple the vise jaw  110  to the machine tool vise  115  (not shown).  
         [0020]    [0020]FIG. 5 depicts a detailed front view of the gripping pads  210 , the vertical clamping surface  225  and the notches  310 . As can be seen, the notches  310  are milled into the surface of the vise jaw  110 , creating a space between each gripping pad  210 . The vertical clamping surface  225  is disposed on the front of each gripping pad  210 .  
         [0021]    [0021]FIG. 6 shows how the vise assembly  100  of the present invention provides a means to securely grip workpieces during machine tool operations. First, a pair of vise jaws  110  is placed onto the left and right side of the machine tool vise  115 . A coupling means, such as a clamp or bolt, is inserted through the attachment openings  140  of the vise jaws  110  and tightened to secure the vise jaws to the machine tool vise. Next, a workpiece  610  is placed on the contact surface  220  of the left and right vise jaws  110 . The machine tool vise  115  is then tightened. As the vise jaws  110  move closer to each other, the vertical clamping surfaces  225  of each vise jaw eventually come into contact with the workpiece  610 . As long as the material hardness of the gripping pads  210  is greater than that of the workpiece  610 , further tightening of the machine tool vise  115  will cause the gripping pads to penetrate and deform the outer surface of the workpiece. The gripping pads  210  will thereby gouge the workpiece  610  a certain amount. This gouging action of the gripping pads  210  into the workpiece  610  supplies a secure and efficient grip on the workpiece. Thus, regardless of the orientation or direction of the force applied to the workpiece by the machine tool, the vise jaws  110  will not allow the workpiece to move or shift in any direction during the machining process.  
         [0022]    In order for the gouging and subsequent gripping action to occur, the hardness of the gripping pads  210  must be greater than that of the workpiece  610 . Therefore, in one aspect of the invention, the gripping pads  210  are made from tool steel. This provides the gripping pads  210  with a hardness greater than that of many machinable materials.  
         [0023]    Once the machining process on the workpiece  610  is completed, the machine tool vise  115  is loosened. As the left and right vise jaws  110  move away from each other, the gripping pads  210  loosen their grip on the workpiece  610 , and the workpiece can then be removed from the vise assembly  100 . A portion of the workpiece  610  may contain marks and gouges at the point where the gripping pads  110  engaged the workpiece. This section of the workpiece may be milled or cut off, if desired, so as not to include it as part of the finished workpiece.  
         [0024]    While the present invention has been described in detail by specific reference to preferred aspects, it is understood that the above description is not limiting of the disclosed invention and variations and modifications thereof may be made without departing from the true spirit and scope of the invention.