Abstract:
The subject invention provides a work support apparatus ( 20 ) for re-grinding a corner of a cutting insert ( 22 ). The work support apparatus ( 20 ) includes a base ( 24 ) pivotable between a horizontal position and an inclined position for re-grinding a positive and a negative cutting insert ( 22 ). A support lever ( 26 ) is mounted to the base ( 24 ) and is rotatable about a pivot axis (P). The support lever ( 26 ) supports a carrier post ( 30 ). An insert holder ( 32 ) positions the cutting insert ( 22 ) for re-grinding and is supported by the carrier post ( 30 ). The insert holder ( 32 ) is connected to the carrier post ( 30 ) by an adjustable device ( 36 ). The insert holder ( 32 ) is adjustable along a holder axis (H) perpendicular to the pivot axis (P). The insert holder ( 32 ) is adjustable for positioning the corner of the cutting insert ( 22 ) to be ground a pre-determined distance from the pivot axis (P) such that the same work support apparatus ( 20 ) may be used for grinding various radii into the cutting insert ( 22 ).

Description:
CROSS REFERENCE TO RELATED APPLICATIONS  
       [0001]     This application claims the benefit of U.S. provisional patent application Ser. No. 60/565,456, filed on Apr. 26, 2004, the disclosure of which is hereby incorporated by reference. 
     
    
     BACKGROUND OF THE INVENTION  
       [0002]     1. Field of the Invention  
         [0003]     The subject invention relates to a work support apparatus for re-grinding a cutting insert around a corner, between edges thereof.  
         [0004]     2. Description of the Prior Art  
         [0005]     The typical work support is supported on a chuck and used in combination with a surface grinder to grind the cutting surfaces into the cutting insert. An example of such a work support apparatus is shown in the U.S. Pat. No. 5,168,661 to Pedersen et. al., (“the &#39;661 patent.”)  
         [0006]     The &#39;661 patent discloses a work support apparatus that includes a work holder for supporting the cutting insert. The work holder is secured to a work spindle that is journaled for rotation in a work head. The work head is rotatably mounted to a base for rotation about a pivot axis extending upwardly from the base. The base is mounted to a table, which is movable in perpendicular and parallel directions relative to the surface grinder. The surface grinder is movable vertically relative to the table. A plurality of electric motors controls the movement of the table and surface grinder, and an operator controls the electric motors. The cutting insert is ground by rotating the gear about the pivot axis and into engagement with the surface grinder.  
         [0007]     When using a work support apparatus as disclosed in the &#39;661 patent to grind cutting inserts, the radius of the corner is determined by the distance between the pivot axis and the surface grinder. If a different radius is desired, an alternative work support having a different relative spacing between the pivot axis and the surface grinder must be installed on the table.  
       SUMMARY OF THE INVENTION AND ADVANTAGES  
       [0008]     The subject invention provides a work support apparatus for re-grinding a cutting insert around a corner between edges. The work support apparatus includes a base. A support lever is pivotably attached to the base for rotation about a pivot axis. The pivot axis extends upwardly from the base. A carrier post extends upwardly from the support lever in spaced relationship to the pivot axis. An insert holder is disposed on the carrier post and extends along a holder axis perpendicular to the pivot axis. The insert holder supports the cutting insert such that the pivot axis extends therethrough. An adjustable device interconnects the insert holder and the carrier post for adjusting the position of the insert holder along the holder axis relative to the pivot axis for determining the radius of the corner of the cutting insert to be re-ground into the cutting insert.  
         [0009]     The subject invention also provides a method of re-grinding a cutting insert around a corner between edges. The method comprises the steps of pre-positioning the cutting insert in a datum position relative to the pivot axis, moving the cutting insert into kissing engagement with a grinding wheel to a start position, moving the cutting insert away from the grinding wheel, and moving the cutting insert back into engagement with the grinding wheel and past the start position to grind the corner. The method further includes the step of adjusting the position of the cutting insert a pre-determined distance from the datum position such that the pivot axis extends through the cutting insert to pre-determine the radius of the corner to be ground.  
         [0010]     Accordingly, the subject invention provides a work support apparatus for grinding a cutting insert that is adjustable to provide for grinding differing radii on the cutting insert without using different work supports for the different radii. The subject invention is therefore a more efficient and cost effective work support apparatus for re-grinding cutting inserts. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0011]     Other advantages of the present invention will be readily appreciated, as the same becomes better understood by reference to the following detailed description when considered in connection with the accompanying drawings wherein:  
         [0012]      FIG. 1  is a side view of the work support apparatus;  
         [0013]      FIG. 2  is an exploded side view of the work support apparatus;  
         [0014]      FIG. 3  is a front view of a stop plate of the work support apparatus;  
         [0015]      FIG. 4  is a side view of the stop plate.  
         [0016]      FIG. 5  is a top view of an insert holder of the work support apparatus;  
         [0017]      FIG. 6  is a side view of the insert holder;  
         [0018]      FIG. 7  is a back view of a carrier post of the work support apparatus;  
         [0019]      FIG. 8  is a side view of the carrier post;  
         [0020]      FIG. 9  is a top view of a support lever of the work support apparatus;  
         [0021]      FIG. 10  is a side view of the support lever;  
         [0022]      FIG. 11  is a top view of a base of the work support apparatus;  
         [0023]      FIG. 12  is a side view of the base;  
         [0024]      FIG. 13  is a top view of a clamping device of the work support apparatus;  
         [0025]      FIG. 14  is a side view of the clamping device. 
     
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT  
       [0026]     Referring to the figures, wherein like numerals indicate like or corresponding parts throughout the several views, a work support apparatus is generally shown at  20  in  FIGS. 1 and 2 . The work support apparatus  20  is for re-grinding a cutting insert  22  around a corner between edges. The work support apparatus  20  includes a base  24 . A support lever  26  is pivotably attached to the base  24  for rotation about a pivot axis P extending upwardly from the base  24 . A carrier post  30  extends upwardly from the support lever  26  in spaced relationship to the pivot axis P. An insert holder  32  is secured to the carrier post  30  and extends along a holder axis H perpendicular to the pivot axis P for supporting the cutting insert  22 . The cutting insert  22  is positioned on the insert holder  32  such that the pivot axis P extends through the corner of the cutting insert  22 . The work support apparatus  20  includes an adjustable device, generally shown at  36 , interconnecting the insert holder  32  and the carrier post  30 . The adjustable device  36  adjusts the position of the insert holder  32  along the holder axis H relative to the pivot axis P for determining the radius of the corner to be ground into the cutting insert  22 .  
         [0027]     The work support apparatus  20  further includes an indexing device, generally shown at  38 , for positioning the insert holder  32  in a datum position parallel to and spaced radially from the pivot axis P. As best shown in  FIGS. 3 and 4 , the indexing device  38  includes a stop plate  40  defining a through bore  42 . Referring back to  FIGS. 1 and 2 , a stop plate fastener  44  attaches the stop plate  40  to the carrier post  30  such that a top end of the stop plate  40  extends above a top surface of the carrier post  30 .  
         [0028]     As best shown in  FIGS. 5 and 6 , the insert holder  32  includes a locating surface  46  parallel to the pivot axis P. A recess  48  is adjacent the pivot axis P for retaining the cutting insert  22  therein. The recess  48  includes at least one locating edge  50  and a pocket  52  located adjacent the at least one locating edge  50 . The locating edges position the cutting insert  22  within the recess  48 . The pocket  52  facilitates the positioning of the cutting insert  22  within the recess  48 . Referring back to  FIG. 1 , the locating surface  46  abuts the stop plate  40  to position the insert holder  32  in the datum position. The insert holder  32  extends from the locating surface  46  forward to a distal end adjacent the pivot axis P.  
         [0029]     Referring to  FIGS. 2, 5 , and  6 , the adjustable device is generally shown at  36  and includes an elongated opening  54  having a length parallel to the holder axis H. A fastener  56  passes through the elongated opening  54  to secure the insert holder  32  to the carrier post  30 . The insert holder  32  is adjustable axially along the holder axis H. The adjustable device  36  includes an indentation  58  disposed about the elongated opening  54  such that a head portion  60  of the fastener  56  is disposed within the indentation  58 .  
         [0030]     When operating the work support apparatus  20 , an operator moves the insert holder  32  forward from the stop plate  40  to place a shim between the locating surface  46  and the stop plate  40 . The operator will then move the insert holder  32  back toward the stop plate  40  tightly sandwiching the shim between the locating surface  46  and the stop plate  40 .  
         [0031]     As best shown in  FIGS. 7 and 8 , the carrier post  30  includes a holder guide, generally shown at  62 , for guiding the insert holder  32  along the holder axis H. The holder guide  62  includes a holder channel  64  defined in the carrier post  30 . The holder channel  64  receives the insert holder  32  such that at least one side of the insert holder  32  engages at least one side of the holder channel  64 .  
         [0032]     Referring back to  FIGS. 1 and 2 , the work support apparatus  20  includes a clamping device, generally shown at  66 , for securing the cutting insert  22  to the insert holder  32 . The clamping device  66  includes a clamping plate  68  having a first clamping ridge  70  and a second clamping ridge  72 . The clamping plate  68  is attached to the insert holder  32  by a clamping fastener  74 . The first clamping ridge  70  contacts the cutting insert  22  positioned within the recess  48 . The second clamping ridge  72  contacts a top surface of the insert holder  32 . The clamping fastener  74  is tightened to apply a downward force to the clamping plate  68 . The clamping plate  68  transfers the downward force to the first  70  and second  72  clamping ridges, thereby securing the cutting insert  22  to the insert holder  32 .  
         [0033]     Referring to  FIGS. 9 and 10 , the support lever  26  includes a carrier post guide, generally shown at  76 . The carrier post guide  76  includes a longitudinal axis L perpendicular to the holder axis H for guiding the carrier post  30  along the longitudinal axis L. The carrier post guide  76  includes a carrier post channel  78  in the support lever  26  for receiving the carrier post  30  therein. Referring to  FIG. 2 , at least one side of the carrier post  30  engages at least one side of the carrier post channel  78 . At least one screw  79  passes through an elongated bore  84  defined by the support lever  26  and into threaded engagement with the carrier post  30  for securing the carrier post  30  to the support lever  26 . The elongated bore  84  allows adjustment of the carrier post  30  along the longitudinal axis L while still maintaining a secure connection between the support lever  26  and the carrier post  30 .  
         [0034]     The carrier post  30  and the support lever  26  define a threaded bore  80  therebetween. An adjustment screw  82  is in threaded engagement with the threaded bore  80 . The adjustment screw  82  axially adjusts the carrier post  30  by threading the adjustment screw  82  inwardly or outwardly from within the threaded bore  80 . The carrier post  30  is adjusted along the longitudinal axis L of the carrier post guide  76  for centering the insert holder  32  on the holder axis H.  
         [0035]     As best shown in  FIGS. 11 and 12 , the base  24  includes a rotatable device, generally shown at  86 , for rotating the cutting insert  22  between a horizontal position and an inclined position. The rotatable device  86  rotates the cutting insert  22  to re-grind the corner of both a positive and a negative cutting insert  22 . The rotatable device  86  includes a first bottom surface  88  of the base  24  and a second bottom surface  90  of the base  24 . The first bottom surface  88  is perpendicular to the pivot axis P for positioning the cutting insert  22  in the horizontal position. The second bottom surface  90  is inclined at an angle relative to the pivot axis P for positioning the cutting insert  22  in the inclined position. Preferably, the second bottom surface  90  is inclined at an eleven-degree angle relative to the first bottom surface  88 .  
         [0036]     The work support apparatus  20  includes at least one stop  92  attached to the base  24  for limiting rotation of the support lever  26  about the pivot axis P. Preferably, the work support apparatus  20  includes a first stop  94  and a second stop  96  disposed on each side of the support lever  26  to limit rotation of the support lever  26  in both a clockwise and a counterclockwise direction.  
         [0037]     Referring back to  FIGS. 1 and 2 , a pivotable connection is generally shown at  98 . The pivotable connection  98  attaches the support lever  26  to the base  24  for rotation about the pivot axis P. The pivotable connection  98  includes a pivot fastener  100  having a smooth shank portion  102  that passes through an aperture  104  defined by the support lever  26  and into threaded engagement with the base  24 . A head portion of the pivot fastener  100  is spaced from the support lever  26  by a first thrust bearing  106  sandwiched between a first thrust washer  108  and a second thrust washer  110 . Likewise, the support lever  26  is spaced from the base  24  by a second thrust bearing  112  sandwiched between a third thrust washer  114  and a fourth thrust washer  116 . The pivot fastener  100  passes through the first thrust washer  108 , the first thrust bearing  106 , the second thrust washer  110 , the support lever  26 , the third thrust washer  114 , the second thrust bearing  112 , and the fourth thrust washer  116  such that the smooth shank portion  102  of the pivot fastener  100  extends downward into the base  24 . A setscrew  118  is advanced into a threaded recess  48  in a front surface of the base  24  and is tightened against the pivot fastener  100  to secure the pivot fastener  100  in place.  
         [0038]     The work support apparatus  20  includes a handle  120  attached to the support lever  26  for operating the work support apparatus  20 . The handle  120  is attached to the support lever  26  by a handle fastener  122  passing through the support lever  26  and into threaded engagement with the handle  120 .  
         [0039]     The work support apparatus  20  as described above is intended for use with a magnetic chuck. The work support apparatus  20  can be used to re-grind a variety of different shaped cutting inserts  22 , including square and triangular inserts. A different insert holder  32  is used for the different shaped cutting inserts  22 .  
         [0040]     The subject invention also provides a method of re-grinding a cutting insert  22  around a corner between a first and a second edge of the cutting insert  22 . When operating the work support apparatus  20 , the operator must first determine the stock removal thickness necessary to sharpen the cutting insert  22 . This is the necessary amount of material to be removed to grind a sharp corner. Next, the operator must determine the existing radius of the cutting insert  22  to be ground. It is preferable to use radius gauges or and optical comparator to determine the existing radius. A proposed radius is then calculated by adding the stock removal thickness to the existing radius. A shim thickness is calculated by an equation specific to the shape of the cutting insert. As shown in the Figures, for a triangular cutting insert, the shim thickness is calculated by multiplying the proposed radius by two. The cutting insert  22  is initially positioned in a datum position parallel to and spaced radially from the pivot axis P. The shim is inserted between the locating surface  46  on the insert holder  32  and the stop plate  40  to move the insert holder  32  from the datum position to a grinding position. The cutting insert  22  is positioned in the insert holder  32  firmly against the locating edges and securely clamped in place.  
         [0041]     The work support apparatus  20  is positioned on the magnetic chuck in either the horizontal position if the operator is grinding a negative cutting insert  22  or the inclined position if the operator is grinding a positive cutting insert  22 . The corner of the cutting insert  22  is positioned in the lower right quadrant of the surface grinder. The operator then advances the cutting insert  22  inward towards the surface grinder until the cutting insert  22  is in kissing engagement with the surface grinder in a start position. At least one dog stop  92  is placed for repeating the start position. The cutting insert  22  is then withdrawn from the surface grinder. To sharpen the cutting insert  22 , the surface grinder is activated and the operator urges the cutting insert  22  back into the surface grinder while rotating the cutting insert  22  back and forth about the pivot axis P until the corner is re-ground.  
         [0042]     The foregoing invention has been described in accordance with the relevant legal standards; thus, the description is exemplary rather than limiting in nature. Variations and modifications to the disclosed embodiments may become apparent to those skilled in the art and do come within the cope of the invention. Accordingly, the scope of legal protection afforded this invention can only be determined by studying the following claims. In addition, the reference numerals in the claims are merely for convenience and are not to be read in any way as limiting.