Abstract:
An improvement in the structure of a worktable for a wood carving machine includes a positioning device provided with a sleeve having a U-shaped recess at the top for mounting a supporting arm of a clamping device, the supporting arm being provided with an eccentric roller close to an intermediate portion thereof and adapted for sliding on the upper edge of the positioning device, and the clamping device being replaceable with a holder which can be moved up and down along a rod and rotated with respect to a cross-shaped sleeve for holding a workpiece in place.

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     This invention is related to an improvement in the structure of a worktable for a wood carving machine and in particular to one having a positioning device and a clamping device on the worktable which can facilitate the positioning of a workpiece. 
     2. Description of the Prior Art As shown in FIGS. 1 and 2, the conventional worktable  11  for a wood carving machine utilizes an adjust bolt  12 , two stationary brackets  13 , a movable bracket  14 , an adjust screw rod  15  and a positioning device  16  to adjust the position of a workpiece. In addition, the positioning device  16  is formed with a hole  17  on which is mounted a holding device  20 . The holding device  20  comprises an L-shaped rod  21 , a rectangular block  22  and a spring leaf  23 . The spring leaf  23  is disposed above the worktable  11  for holding a workpiece being processed. However, the positioning device  16  can only be moved to and fro and cannot be used for adjusting the carving angle and the inclination of the workpiece, thereby limiting the processing range and method and therefore causing much inconvenience in operation. 
     Therefore, it is an object of the present invention to provide an improvement in the structure of a worktable for a wood carving machine which can obviate and mitigate the above-mentioned drawbacks. 
     SUMMARY OF THE INVENTION 
     This invention is related to an improvement in the structure of a worktable for a wood carving machine and in particular to one having a positioning device and a clamping device on the worktable which can facilitate the positioning of a workpiece. 
     It is the primary object of the present invention to provide an improvement in the structure of a worktable for a wood carving machine which utilizes a U-shaped recess on the top of a sleeve to mount a clamping device for keeping a workpiece in place. 
     It is another object of the present invention to provide an improvement in the structure of a worktable for a wood carving machine which includes a clamping device having a supporting arm provided at the rear side with an eccentric roller adapted for sliding on an upper edge of a positioning device. 
     It is a further object of the present invention to provide an improvement in the structure of a worktable for a wood carving machine having a holder which can be moved up and down along a rod and rotated with respect to a cross-shaped sleeve for holding a workpiece in place. 
     The foregoing objects and summary provide only a brief introduction to the present invention. To fully appreciate these and other objects of the present invention as well as the invention itself, all of which will become apparent to those skilled in the art, the following detailed description of the invention and the claims should be read in conjunction with the accompanying drawings. Throughout the specification and drawings identical reference numerals refer to identical or similar parts. Many other advantages and features of the present invention will become manifest to those versed in the art upon making reference to the detailed description and the accompanying sheets of drawings in which a preferred structural embodiment incorporating the principles of the present invention is shown by way of illustrative example. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is an exploded view of a prior art worktable for a wood carving machine; 
     FIG. 2 is a perspective view of the prior art worktable for a wood carving machine; 
     FIG. 3 is an exploded view of the present invention; 
     FIG. 4 is another exploded view of the present invention; 
     FIG. 5 is still another exploded view of the present invention; 
     FIG. 6 is a perspective view of the present invention; 
     FIGS. 7 and 8 illustrate how to adjust the position of the clamping device according to the present invention; 
     FIG. 8 is another working view of the present invention; 
     FIG. 9 is a first working view of the present invention; and 
     FIG. 10 is a second working view of the present invention. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
     For the purpose of promoting an understanding of the principles of the invention, reference will now be made to the embodiment illustrated in the drawings. Specific language will be used to describe same. It will, nevertheless, be understood that no limitation of the scope of the invention is thereby intended, such alterations and further modifications in the illustrated device, and such further applications of the principles of the invention as illustrated herein being contemplated as would normally occur to one skilled in the art to which the invention relates. 
     With reference to the drawings and in particular to FIGS. 3 and 4 thereof, the present invention utilizes two adjust bolts, two stationary brackets  34 , a movable bracket  45 , an adjust screw rod  35  on a platform  31  to connect with a positioning device  41  for holding a workpiece in place. A clamping device  50  is mounted on the front side of the positioning device  41  by a handle  57  for clamping a workpiece to be processed. 
     As shown in FIGS. 4,  5  and  6 , the platform  31  is formed with a rectangular opening  311  in which is fitted a core plate  33  by screws  32 . The core plate  33  has a center hole  331  and a plurality of radial slots  332 . The two stationary brackets  34  are fixedly secured to one side of the platform  31  for engaging with the adjust screw rod  35 . 
     The positioning device  41  has two upwardly extending lugs  412  at two sides thereof each having a hole  411 . An axle  44 , on which is fitted a sleeve  43 , extends through the two holes  411  of the two lugs  412  and is kept in place by two countersunk screws  42  extending through the lugs  412  to bear thereagainst. The inside of the sleeve  43  is provided with a bearing  431  and the top of the sleeve  43  has a U-shaped recess  432  on which is mounted a supporting arm  51  of the clamping device  50  by the handle  57 . The movable bracket  45  is fixedly secured to one side of the positioning device  41  and engaged with the adjust screw rod  35 . The positioning device  41  is mounted on one side of top of the platform  31  by two adjust bolts  46 . 
     The clamping device  50  comprises a supporting arm  51 , a positioning plate  52 , a baffle  53 , a bracket  54 , an adjust rod  55 , an adjust screw rod  56  and two handles  57  and  58 . The clamping device  50  is fixedly mounted on the U-shaped recess  432  of the sleeve  43  of the positioning device  41 . 
     A seat  511  extends from the rear side of the supporting arm  51  and has an upper and lower lugs  512  between which is arranged the positioning plate  52  by bolts  513 . An adjust screw  514  extends through the upper lug  512  to lock the positioning plate  52  in place. The rear side of the supporting arm  51  is provided with an eccentric roller  515  below the seat  511 . The clamping device  50  is fixedly mounted on the U-shaped recess  432  of the sleeve  43  of the positioning device  41  so that the roller  515  is rotatably arranged on the upper edge  413  of the positioning device  41 . 
     The positioning plate  52  is a generally rectangular in shape and having a curved groove  521  at one of its upper comers. An angular baffle  53  is mounted on the positioning plate  52  by an adjust bolt  523  and a bolt  522  so that the angular baffle  53  can be adjusted to rotate with respect to the bolt  522 . The rear side of the positioning plate  52  has a lug  524  fitted between the two lugs  512  of the supporting arm  51  by bolts  513  thus enabling the positioning plate  52  to be rotated with respect to the bolts  513  when the adjust screw  514  is loosened to disengage with the positioning plate  52 . 
     The angular baffle  53  is mounted on the front side of the positioning plate  52  and can be oscillated along the curved groove  521  of the positioning plate  52 . 
     The bracket  54  is a generally T-shaped member having an end fixedly mounted on the front side of the positioning plate  52  by a screw  541 . An adjust rod  55  is mounted on the bracket  54  by a pin  542  and a bolt  543 . An adjust screw rod  56  extends through the slot of the adjust rod  55  to engage with a head  561  for holding a workpiece on the positioning plate  52 . 
     Referring to FIG. 7, the platform  31  is mounted on a base  60  so that the cutter  61  extends upwardly through the center hole  311  of the core plate  33 . As shown in FIG. 8, the clamping device  50  is changed in position by moving the sleeve  43  along the axle  44 . 
     Turning now to FIGS. 9 and 10, a holder  70  is mounted on the hole  413  of the positioning device  41 , which comprises an L-shaped rod  71 , a cross-shaped sleeve  72  and a rod  75  provided at one end with a roller  73  and the other end with a generally triangular member  74  so that the rod  75  can be moved up and down or rotated with respect to the sleeve  72  for holding a workpiece in place. 
     Accordingly, the present invention can be operated as follows: 
     1. The positioning device  41  can be adjusted in position by loosening the adjust bolts  46  at the rear side of the positioning device  41  and tuning the adjust screw rod  35 . 
     2. The workpiece can be processed by holding the two handles  57  and  58  and moving the sleeve  43  along the axle  44  so as to move the clamping device  50 . 
     3. The position of the workpiece on the positioning plate  52  can be adjusted by loosening the bolts  512  and rotating the positioning plate  52  with respect to the supporting arm  51 . 
     4. The angular baffle  53  can be adjusted by loosening the bolts  522  and  523  thereby enabling the angular baffle  53  to be rotated to adjust the angular position of the workpiece. 
     5. The workpiece can be secured to the positioning plate  52  by turning the adjust screw rod  56 . 
     6. The clamping device  50  can be dismantled from the positioning device  41  and replaced with a holder  70 . 
     It should be noted, however, that the base  60  for supporting the platform  31  and the control circuit for the wood carving machine are well known in the art and not considered parts of the invention. 
     It will be understood that each of the elements described above, or two or more together may also find a useful application in other types of methods differing from the type described above. 
     While certain novel features of this invention have been shown and described and are pointed out in the annexed claim, it is not intended to be limited to the details above, since it will be understood that various omissions, modifications, substitutions and changes in the forms and details of the device illustrated and in its operation can be made by those skilled in the art without departing in any way from the spirit of the present invention.