Abstract:
A work holder which is adapted to hold a workpiece firmly in place for machining operations with respect to a machine tool. The workpiece is fashioned with a dovetail protuberance, which protuberance is designed to affix the workpiece to the work holder to the machining operations. Once the machining is completed, the dovetail protuberance may be removed in any convenient manner. Thus, the finished product may not then exhibit the former protuberance.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application is a continuation-in-part of U.S. application Ser. No. 12/611,894, filed Nov. 3, 2009 which claims the benefit of U.S. Provisional Application Ser. No. 61/110,810, filed Nov. 3, 2008, the disclosure of each of which is hereby incorporated herein by reference in its entirety. 
    
    
     SUMMARY 
     The work holder is an intermediary dovetail fixture, which is adapted to hold a workpiece firmly in place for machining operations with respect to a machine tool, for example, a 5-axis vertical machining center, e.g, see www.matsuura.co.jp. The workpiece is fashioned with a dovetail protuberance, which protuberance is designed to affix the workpiece to the work holder prior to the machining operations. Once the machining is completed, the dovetail protuberance is removed in any convenient manner, such as by being ground away. Thus, the finished product will not exhibit the former protuberance. 
    
    
     
       DRAWINGS 
       The attached illustrations depict the work holder, in which: 
         FIG. 1  is a perspective view of a workpiece secured to the work holder; 
         FIG. 2  is a cross-section of the mechanism taken along section line  2 - 2  of  FIG. 1 , by which the workpiece is secured to the work holder; 
         FIG. 3  depicts a perspective view of the work holder having a slot which is formed in its upper surface and which, at its opposed sides, has a slanted or dovetail side wall and a 90.degree. trifurcated straight-up side wall; 
         FIG. 4  is a partial cross-section of the work holder in perspective; 
         FIG. 5  is a side view of the work holder also depicting the slot with its slanted dovetail side wall and its 90.degree. trifurcated straight-up side wall; 
         FIG. 6  is a view of the work holder taken 90.degree. with respect to that shown in  FIG. 5 ; 
         FIG. 7  is a cross-section of the work holder taken along section line  7 - 7  of  FIG. 6 ; 
         FIG. 8  is a top view of the work holder as previously shown; 
         FIG. 9  is a bottom view of the work holder; 
         FIG. 10  is a cross-sectional view of the work holder taken along section line  10 - 10  of  FIG. 9 ; 
         FIG. 11  a side view of one of the housings of the clamps used in the work holder used to grip the dovetail of the workpiece; 
         FIG. 12  is a side view of the swing clamp housing shown in  FIG. 11 , but turned 90.degree. therefrom; 
         FIG. 13  is a cross-sectional view of the clamp housing taken along section line  13 - 13  of  FIG. 12 ; and 
         FIG. 14  is an end view of the clamp illustrated in  FIGS. 11-13 . 
     
    
    
     DESCRIPTION OF PREFERRED EMBODIMENT 
     While the present invention is described herein with reference to illustrative embodiments for particular applications, it should be understood that the invention is not limited thereto. Those having ordinary skill in the art and access to the teachings provided herein will recognize additional modifications, applications, and embodiments within the scope thereof and additional fields in which the present invention would be of significant utility. 
     As illustrated in  FIGS. 1 and 2 , a work holder or support  30  is designed to firmly support, hold and grip a workpiece  32 . As further shown in  FIGS. 3-5  and  7 , work holder is formed with a partial dovetail slot  34  having a bottom surface  36 , a slanted side  38  that forms a dovetail and a trifurcated straight-up side  40 , that is, side  40  is formed with a pair of openings  42 . The slanted side  38  extends from the bottom surface  36  and terminates at a side top support surface  39  that extends alone one side of the partial dovetail slot  34 . The trifurcated straight-up side  40  on the other side of the partial dovetail slot terminates in a corresponding trifurcated side top support surface  41  were each trifurcated section is substantially perpendicular to the corresponding section of the trifurcated straight-up sides  40 . The slot depth  37   a  is substantially the same across the width of the partial dovetail slot  34  between the side top support surface  39  and the trifurcated side top support surface  41 . Side  38  is slanted at an angle which is less than 90 degrees with respect to bottom surface  36  while straight-up side  40  is generally 90 degrees to the bottom surface,  36  although this orthogonal inclination is not critical, in that the trifurcation of side  40  (see also  FIG. 6 ) provides openings  42  for embracing a pair of clamps, e.g., hook clamps  48 . While the central section of side  40  is illustrated as wider than its outer sides, this need not be so. 
     Workpiece  32  is formed with an integral protuberance or projection  44  (see  FIGS. 1 and 2 ) that is formed as shaped on the workpiece when it is fabricated. On its opposed edges, protuberance  44  is provided with a pair of dovetail sides  46   a  and  46   b . Dovetail side  46   a  is disposed to contact slanted side  38  of dovetail slot  34  while dovetail side  46   b  is positioned adjacent to but spaced from trifurcated straight-up side  40  and openings  42  for reasons to be presently discussed also with reference to  FIGS. 11-14  in conjunction specifically with  FIG. 2 . The protuberance  44  also defines a slot facing surface  35  for facing the bottom surface  36  and workpiece support surfaces on each side of the protuberance. A first workpiece support surface  31  is positioned to face the side top support surface  39  and a second workpiece support surface  33  is positioned to face the trifurcated side top surface  41 . The thickness  37   b  of the protuberance  44  is approximately the same as the slot depth  37   a  for reasons to be explained hereafter. 
     Accordingly, a pair of clamps  48  (as modified from a generic form) are disposed to reside within respective bores  49  in work holder  30 . Each clamp includes a housing  50  (see FIGS.  2  and  11 - 14 ) and a screw  52  having an enlarged head  54  (see also  FIG. 2 ), in which an Allen head wrench opening  56  is disposed, and a shank  58 . Shank  58  has a threaded end  60  for engagement with threaded openings  62  in work holder  30 . 
     As best shown in  FIGS. 2 and 13 , clamp  50  includes a tubular stem  63 , and a recess  64  is shaped in each clamp housing  50  to provide a shoulder  66 . A corresponding shoulder  68 , which terminates bore  49 , faces clamp housing shoulder  66 . Springs  70  are fitted about shank  58  of screw  50  and respectively abut at their ends against shoulders  66  and  68 . Housing  50  is also provided with a head  78  at one end of tubular stem  63 . An extension  72  (see  FIGS. 12 and 14 ) extends from head  78  and includes a slanted surface  74  which is adapted to engage dovetail side  46   b  of workpiece protuberance  44  (see also  FIG. 2 ). The slanted surface  74  terminates in a head top support surface  79 . The distance  83  between the head top support surface  79  and the center axis  73  of the tubular stem  63  is defined so that the head top support surface  79  is generally in planar alignment with the trifurcated side top support surface  41  when the clamp  50  is in position in the work holder bore  49 . Slanted surface  74  in part differentiates clamps  48  from the generic, e.g., hook clamp form. Head  78 , terminating shank  63 , further has an opening  80  for retention of screw head  54  and defines a flat bearing surface  81 . 
     In operation, as each screw  52  is threaded into threaded opening  62 , against the bias of spring  70 , each enlarged head  54  of each screw  52  bears against its respective surface  81  on housing  50 . This movement causes slanted surfaces  74  of the respective housings to move within and to be guided by openings  42  and to engage dovetail side  46   b  on protuberance  44  as well as to press opposite protuberance dovetail side  46   a  of workpiece  32  against dovetail slanted side  38 . As each clamp  50  is further tightened, the slanted surface  74  not only clamps the protuberance  44  of the workpiece laterally between the dovetail side  46   a  and  46   b  but also pulls the workpiece  32  vertically, that is, toward the work holder  30  as the slanted surfaces slide against one another in response to the tightening. The result is that when fully tightened, the slot facing surface  35  of the workpiece will be urged to press against the bottom surface  36  of the dove tail slot  34  and the first workpiece support surface  31  will be urged to press against the side top support surface  39  of the work holder  30  and the second workpiece support surfaces  33  will be urged to press against the trifurcated side top support surface  41  and the head top support surface  79  which is general alignment with the trifurcated side top support surface  41 . As a consequence, work holder  30  and workpiece  32 , through its protuberance  44 , are secured into a fixed engagement to and within work holder  30  both laterally though the clamping movement as the screw  52  to urged the opposing dovetail surfaces of the work piece and the support  30  into contact and vertically as the opposing dovetail surfaces pull the support surfaces into contact in a direction perpendicular to the center axis  73  to thereby provide a work holder which holds a workpiece firmly in place vertically and horizontally with respect to a machine tool. 
     A machine screw  76  (see  FIG. 3 ) may be placed in within surface  36  of slot  34  to act as a positioning stop for the workpiece. 
     After all machining operations are completed on the workpiece, screws  52  are unscrewed to permit the workpiece to be released from the work holder. Protuberance  44  may be then machined away and accordingly removed from the workpiece. 
     Thus, the present invention has been described herein with reference to a particular embodiment for a particular application. Those having ordinary skill in the art and access to the present teachings will recognize additional modifications, applications and embodiments within the scope thereof. 
     It is therefore intended by the appended claims to cover any and all such applications, modifications and embodiments within the scope of the present invention.