Abstract:
A multipurpose bench grinder ( 1 ) is disclosed that includes a body including a base ( 2 ) and a housing ( 3 ); a motor mounted in the body and having a driving shaft ( 6 ) extending out of both sides of the body; a right grinder assembly ( 4 ) including a first grind wheel ( 45 ) and a parallel second grind wheel ( 47 ) being separate from the first grind wheel ( 45 ) by a predetermined gap; and a left grinder assembly ( 7 ) including a third grind wheel ( 77 ). Each of the grind wheels ( 45, 47, 77 ) is operatively connected to the driving shaft ( 6 ) such that in response to activating the driving shaft ( 6 ) the first and the second grind wheels ( 45, 47 ) together are adapted to sharpen a knife or a sickle placed therebetween or the third grind wheel ( 77 ) is adapted to sharpen a pair of scissors.

Description:
BACKGROUND OF THE INVENTION 
       [0001]    1. Field of Invention 
         [0002]    The invention relates to bench grinders and more particularly to a multipurpose bench grinder including a left grinder assembly having a single grind wheel for sharpening a pair of scissors, and a right grinder assembly having a pair of closely opposite grind wheels for sharpening a knife or sickle. 
         [0003]    2. Description of Related Art 
         [0004]    Bench grinders are well known devices. A typical type of bench grinder has a single grind wheel for sharpening a knife. 
         [0005]    Another type of bench grinder as disclosed in Taiwanese Utility Model Patent No. M271,657 has left and right grinder assemblies each having a single grind wheel of the same. In other words, it is only a bench grinder capable of sharpening two tools of the same kind (e.g., knives) at the same time. 
         [0006]    Still, there have been numerous suggestions in prior patents for bench grinder. For example, U.S. Pat. No. 5,525,095 discloses a bench grinder having a series of improvements. Thus, it is desirable to provide a novel multipurpose bench grinder having left and right grinder assemblies for sharpening more than one kind of tool in order to overcome the inadequacies of the prior art. 
       SUMMARY OF THE INVENTION 
       [0007]    It is therefore one object of the invention to provide a multipurpose bench grinder comprising a body including a base and a housing; a motor mounted in the body and having a driving shaft extending out of both sides of the body; a right grinder assembly including a first grind wheel and a second grind wheel being parallel with the first grind wheel and being separate therefrom by a predetermined gap; and a left grinder assembly including a third grind wheel, wherein each of the grind wheels is operatively connected to the driving shaft such that in response to activating the driving shaft the first and the second grind wheels together are adapted to sharpen a knife or a sickle placed therebetween or the third grind wheel is adapted to sharpen a pair of scissors. 
         [0008]    The above and other objects, features and advantages of the invention will become apparent from the following detailed description taken with the accompanying drawings. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0009]      FIG. 1  is an exploded view of a first preferred embodiment of bench grinder according to the invention; 
           [0010]      FIG. 2  is an enlarged view of major components of the right grinder assembly; 
           [0011]      FIG. 3  is a sectional view of the right grinder assembly of  FIG. 2  assembled with the driving shaft and other components; 
           [0012]      FIG. 4  is an enlarged view of major components of the left grinder assembly; 
           [0013]      FIG. 5  is a sectional view of the left grinder assembly of  FIG. 4  assembled with the driving shaft and other components; 
           [0014]      FIG. 6  is an environmental view of the bench grinder with a knife being sharpened by the right grinder assembly; 
           [0015]      FIG. 7  is an environmental view of the bench grinder with a pair of scissors being sharpened by the left grinder assembly; 
           [0016]      FIG. 8  is an environmental view of the bench grinder with a sickle being sharpened by the right grinder assembly by removing the case of the right grinder assembly; and 
           [0017]      FIG. 9  is an environmental view of the bench grinder with a knife being sharpened by the millstone. 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0018]    Referring to  FIG. 1 , a multipurpose bench grinder  1  in accordance with a first preferred embodiment of the invention comprises a base  2 , a housing  3  mounted on the base  2 , an AC motor (not shown) mounted in the base  2  and the housing  3 , the motor having a driving shaft  6  extending out of both sides of the base  2  and the housing  3 , a right grinder assembly  4 , a left grinder assembly  7 , and a millstone  5  mounted on a top of the housing  3 . Left and right grinder assemblies  4  and  7  are subjects of the invention and they will be discussed in detail below. 
         [0019]    Referring to  FIGS. 2 and 3  in conjunction with  FIG. 1 , the right grinder assembly  4  comprises a cylindrical abutment member  43  including a central, hollow cylinder  431  projecting from the right side, the cylinder  431  having a hexagonal outer surface and a circular inner surface, and an annular groove  432  defined between the cylinder  431  and an annular outer surface of the abutment member  43 , a first spring  44 , a first grind wheel  45  including a central, hollow cylinder  451  projecting from the left side and a right circular recess  452  having its bottom center in communication with the cylinder  451  (i.e., the first grind wheel  45  is hollow), a ring  46 , a second grind wheel  47  including a central, hollow cylinder  471  projecting from the right side and a left circular recess  472  having its bottom center in communication with the cylinder  471  (i.e., the second grind wheel  47  is hollow), a second spring  48 , and a cylindrical member  49  including a staged, central, hollow cylinder  491  projecting from the left side, the cylinder  491  having a hexagonal outer surface on the right portion and a circular inner surface, and a left annular groove  492  having its bottom center in communication with the cylinder  491  (i.e., the cylindrical member  49  is hollow). 
         [0020]    In assembly, the driving shaft  6  inserts through the above components of the right grinder assembly  4  to be threadedly secured to a fastener (e.g., nut)  8  at its threaded end. As a result, the first spring  44  is compressed between the groove  432  and a hollow, intermediate neck (not numbered) of the first cylinder  45 . The second spring  48  is compressed between the groove  492  and a hollow, intermediate neck (not numbered) of the second grind wheel  47 . End of the cylinder  431  is fastened in the first grind wheel  45  and end of the cylinder  491  is securely fitted in the cylinder  431 . Also, the cylinder  491  is fastened in the neck of the second grind wheel  47 . The first grind wheel  45  is in close proximity to the second grind wheel  47 . The ring  46  is fastened between the recess  452  of the first cylinder  45  and the recess  472  of the second grind wheel  47 . A portion of the cylinder  491  proximate the end thereof is fastened by the ring  46 . Therefore, an activation of the bench grinder  1  (i.e., the motor) will cause both the grind wheels  45  and  47  to rotate in a speed the same as the driving shaft  6 . 
         [0021]    The right grinder assembly  4  further comprises a substantially half cylindrical upper case  41  including two tabs  411  at rear and front bottom edges respectively, and a curved top opening  412  having both ends substantially terminated at the tabs  411 , and a substantially half cylindrical lower case  42  including two slots  421  at rear and front top edges respectively, two projections  422  at rear and front top left corners respectively, and a cavity  423  on a left edge. On either side of the base  2  there are provided two rear and front slots  21  respectively and a bottom protrusion  22 . 
         [0022]    In assembly, the cavity  423  is put on the protrusion  22  and the projections  422  are inserted into the slots  21  for fastening the lower case  42  and the base  2  together. Further, the tabs  411  are inserted into the slots  421  for fastening the upper case  41  and the lower case  42  together. As a result, the right grinder assembly  4  is assembled with the top opening  412  being open to both the grind wheels  45  and  47 . 
         [0023]    Referring to  FIGS. 4 and 5  in conjunction with  FIG. 1 , the left grinder assembly  7  comprises a cylindrical abutment member  73  including a central, hollow cylinder  731  projecting from the right side, the cylinder  731  having a hexagonal outer surface and a circular inner surface, and an annular groove  732  defined between the cylinder  731  and an annular outer surface of the abutment member  73 , a third spring  74 , a staged shell  75  including a central, hollow cylinder  751  projecting from the left side, a right circular recess  752  having an outer surface formed as an annular trough  754 , and an intermediate, hexagonal hole  753  at a bottom of the recess  752  being in communication with the cylinder  751 , a ring  76  having a separate, large, hollow frusto-conical member  761 , a third grind wheel  77  including a central, hollow cylinder  771  projecting from the right side and a left circular recess  772  having its bottom center in communication with the cylinder  771  (i.e., the third grind wheel  77  is hollow), a fourth spring  78 , and a cylindrical member  79  including a staged, central, hollow cylinder  791  projecting from the left side, the cylinder  791  having a hexagonal outer surface on the right portion and a circular inner surface, and a left annular groove  792  having its bottom center in communication with the cylinder  791  (i.e., the cylindrical member  79  is hollow). 
         [0024]    In assembly, the driving shaft  6  inserts through the above components of the left grinder assembly  7  to be threadedly secured to a fastener (e.g., nut)  8  at its threaded end. As a result, the third spring  74  is compressed between the groove  732  and a hollow, intermediate neck (not numbered) of the shell  75 . The fourth spring  78  is compressed between the groove  792  and a hollow, intermediate neck (not numbered) of the third grind wheel  77 . End of the cylinder  731  is fastened in the shell  75  and end of the cylinder  791  is securely fitted in the cylinder  731 . Also, the cylinder  791  is fastened in a hollow, intermediate neck (not numbered) of the third grind wheel  77 . The ring  76  is fastened between the recess  772  of the third grind wheel  77  and the recess  752  of the shell  75 . A portion of the cylinder  791  proximate the end thereof is fastened by the ring  76 . The frusto-conical member  761  is securely put on the trough  754  and is in close proximity to the third grind wheel  77 . Therefore, an activation of the bench grinder  1  (i.e., the motor) will cause the third grind wheel  77  to rotate in a speed the same as the driving shaft  6 . 
         [0025]    The left grinder assembly  7  further comprises a substantially half cylindrical upper case  71  including two tabs  711  at rear and front bottom edges respectively, and a curved top opening  712  having both ends substantially terminated at the tabs  711 , and a substantially half cylindrical lower case  72  including two slots  721  at rear and front top edges respectively, two projections  722  at rear and front top right corners respectively, and a cavity  723  on a right edge. 
         [0026]    In assembly, the cavity  723  is put on the protrusion  22  and the projections  722  are inserted into the slots  21  for fastening the lower case  72  and the base  2  together. Further, the tabs  711  are inserted into the slots  721  for fastening the upper case  71  and the lower case  72  together. As a result, the left grinder assembly  7  is assembled with the top opening  712  being open to the third grind wheel  77 . 
         [0027]    Referring to  FIG. 6  in conjunction with  FIG. 3 , a first operation of the invention will be described in detailed below. In response to activating the bench grinder  1 , cutting edge of a knife A is placed between the first and the second grind wheels  45  and  47  and is in contact with both for sharpening after inserting into the opening  412 . 
         [0028]    Referring to  FIG. 7  in conjunction with  FIG. 5 , a second operation of the invention will be described in detailed below. In response to activating the bench grinder  1 , cutting edge of a pair of scissors B is in contact with the third grind wheel  77  for sharpening after inserting into the opening  712 . 
         [0029]    Referring to  FIG. 8  in conjunction with  FIGS. 1 and 3 , a third operation of the invention will be described in detailed below. Both the upper and lower cases  41  and  42  are removed. In response to activating the bench grinder  1 , cutting edge of a sickle C is placed between the first grind wheel  45  and the second grind wheel  47  and is in contact with both for sharpening. 
         [0030]    Referring to  FIG. 9  in conjunction with  FIG. 1 , a second preferred embodiment of the invention is shown. A millstone  5  is mounted on a top of the housing  3 . A user thus can sharpen the knife A using the millstone  5 . 
         [0031]    While the invention herein disclosed has been described by means of specific embodiments, numerous modifications and variations could be made thereto by those skilled in the art without departing from the scope and spirit of the invention set forth in the claims.