Abstract:
The present invention relates to tools with replaceable tips and, more particularly, to arrangements for securing replaceable tips to tip holders. The tool includes a tip including a working end, a connecting end, and a radially extending abutment surface; a tip holder including a mating end for mating with the connecting end and a radially extending supporting surface for abutting against the abutment surface to limit axial movement of the tip relative to the tip holder. The connecting end is non-circular and includes a groove. The tool includes an assembly including the tip and the tip holder arranged such that, upon relative rotation of the tip and the tip holder in a connecting direction, an axial force is exerted on the groove and causes the abutment surface to move toward the supporting surface.

Description:
The present invention relates to tools with replaceable tips and, more particularly, to arrangements for securing replaceable tips to tip holders. 
   It is often extremely important in operations such as machining of metal or other workpieces that the location of a cutting edge of a cutting tool be precisely controlled and controllable. Complex machinery is provided to mill, drill, bore, or otherwise perform shaping operations on workpieces by precisely controlling the location of a cutting tool relative to the workpiece. Cutting tools often include replaceable inserts or cutting heads that are attached to permanent toolholders such as shanks that are moved relative to the workpiece. 
   The accuracy of the mounting of the cutting inserts or heads relative to the toolholder is a factor in the accuracy of the operation to be performed on the workpiece. In the case, for example, of a rotating tool, an insert or tool head or tip that is displaced axially relative to a rotating shank to which it is attached can damage the workpiece and may necessitate the rejection of an expensive part. It is therefore desirable to accurately locate the working portion of the tool tip relative to the shank and to keep the tool tip securely held in place relative to the shank. 
   Also, in certain tools, the tool tip is fastened to the shank by gripping an external surface of the tool tip with another tool, such as a wrench. In other tools, the tool tip does not lend itself to being gripped by a wrench. It is desirable to provide an arrangement that does not require gripping of an exterior surface of a tool tip by a tool such as a wrench. 
   In accordance with an aspect of the present invention, a tool includes a tip including a working end, a connecting end, and a radially extending abutment surface. The tool also includes a tip holder including a mating end for mating with the connecting end and a radially extending supporting surface for abutting against the abutment surface to stop axial movement of the tip relative to the tip holder. The connecting end is non-circular and includes a groove, and the tool includes an assembly including the tip and the tip holder arranged such that, upon relative rotation of the tip and the tip holder in a connecting direction, an axial force is exerted on the groove and causes the abutment surface to move toward the supporting surface. 
   In accordance with another aspect of the present invention, a tool tip includes a working end, a connecting end, and a radially extending abutment surface facing away from the working end between the working end and the connecting end. The connecting end is non-circular and includes a groove, and the tool tip is arranged such that, upon relative rotation of the tip and a tip holder in a connecting direction, the groove is adapted to bear an axial force that causes the abutment surface to move toward a supporting surface of the tip holder. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The features and advantages of the present invention are well understood by reading the following detailed description in conjunction with the drawings in which like numerals indicate similar elements and in which: 
       FIG. 1A  is a perspective view and  FIGS. 1B and 1C  are side cross-sectional views of a tool according to an embodiment of the present invention; 
       FIG. 2  is a side plan view of a cutting tip for the tool of  FIGS. 1A-1C ; 
       FIG. 3  is a side cross-sectional view of a cutting tip holder for the tool of  FIGS. 1A-1C ; 
       FIGS. 4A and 4B  are side cross-sectional and bottom plan views of an outer sleeve portion for the tool of  FIGS. 1A-1C ; 
       FIGS. 5A and 5B  are side cross-sectional and bottom plan views of an inner sleeve portion for the tool of  FIGS. 1A-1C ; 
       FIG. 6  is a side cross-sectional view of a tool according to another embodiment of the present invention; 
       FIG. 7  is an exploded perspective view of the tool of  FIG. 6 ; and 
       FIG. 8  is a side cross-sectional view of a tool according to another embodiment of the present invention. 
   

   DETAILED DESCRIPTION 
   A tool  21  having a replaceable working portion according to an embodiment of the present invention is seen in  FIGS. 1A-1C . The tool  21  is a cutting tool, although the present invention has applications in areas other than in cutting tools with replaceable working portions. The tool  21  can include a cutting tip  23  as seen in  FIG. 2 . The cutting tip  23  can include a working end  25  and a connecting end or shank end  27 . The shank end  27  has an external groove  29  therein. The external groove  29  can be, but need not be, a circumferential groove extending around the entire circumference of the shank end  27 . The cutting tip  23  also includes a radially extending abutment surface  31  facing away from the working end  25  between the working end and the shank end  27 . 
   The tool  21  can also include a cutting tip holder  33  as seen in  FIG. 3 . The cutting tip holder  33  includes an internal axially extending opening  35  for receiving the shank end  27  and a radially extending supporting surface  37  for abutting against the abutment surface  31  of the cutting tip  23  to limit axial movement of the cutting tip relative to the cutting tip holder. The distance between the abutment surface  31  and the distal tip of the working end  25  is ordinarily precisely controlled to ensure that the cutting edge(s) of the working end are located where they are intended to be located. The internal axially extending opening  35  includes an internally threaded portion  39 . 
   As seen in  FIGS. 1B and 1C , the tool  21  can also include a sleeve arrangement  41  disposed between the shank end  27  and an internal surface  43  of the internal axially extending opening  35 . The sleeve arrangement  41  includes an externally threaded member  45  adapted to engage the internally threaded portion  39  of the cutting tip holder  33 . The sleeve arrangement  41  is adapted to engage the external groove  29  and move the cutting tip  23  such that the abutment surface  31  of the cutting tip moves toward the supporting surface  37  of the cutting tip holder  33  when the externally threaded member  45  is rotated relative to the cutting tip holder. 
   In the tool  21  shown in  FIGS. 1B and 1C , the sleeve arrangement  41  can include an internal groove  47  and a force transmitting element  49  movably disposed in the internal groove and the external groove  29 . The internal groove  47  can be, but need not be, a circumferential groove that extends around an entire internal circumference of the sleeve arrangement  41  or part of the sleeve arrangement. The sleeve arrangement  41  can include an outer sleeve portion  51  as seen in  FIGS. 4A and 4B  having a second internal axially extending opening  53  with an internal surface  55  in which the internal groove  47  is provided. The sleeve arrangement  41  can also include an inner sleeve portion  57  as seen in  FIGS. 5A and 5B  at least partially disposed inside the second internal axially extending opening  53  of the outer sleeve portion  51  as seen in  FIG. 1B  and having at least one radially extending opening  59  through which the force transmitting element  49  extends. 
   In the tool  21  of  FIG. 1B , the externally threaded member  45  may be non-rotatably fixed to the outer sleeve portion  51  ( FIG. 4A ). The externally threaded member  45  may include a non-circular internal opening  61  ( FIG. 4B ). The shank end  27  of the cutting tip  23  may include a non-circular end  62  adapted to be received in the non-circular opening  61  so that the cutting tip  23  is axially movable but non-rotatable relative to the externally threaded member  45 . If, as seen in  FIG. 1B , the non-circular end  62  does not extend all the way through the non-circular opening  61 , a suitable non-circular tool (not shown) such as a hexagonal Allen wrench (when the non-circular opening  61  is hexagonal) may be used to turn the externally threaded member  45  (and the outer sleeve portion  51  fixed thereto) relative to the cutting tip holder  33  by extending the non-circular tool through the internal axially extending opening  35  of the cutting tip holder. If, as seen in the embodiment described in connection with  FIGS. 6 and 7 , the non-circular end  162  does extend all the way through the non-circular opening  161 , a suitable non-circular tool (not shown) such as a hexagonal socket wrench (when the non-circular end  162  is hexagonal) may be used to turn the externally threaded member  145  relative to the cutting tip holder  133  by extending the non-circular tool through the internal axially extending opening  135  of the cutting tip holder. 
   As seen in  FIG. 1B , the inner sleeve portion  57  can include a radially extending second abutment surface  63  and the internal axially extending opening  35  of the cutting tip holder  33  can include a radially extending second supporting surface  65  against which the abutment surface  63  of the inner sleeve portion is adapted to abut when the axial abutment surface  31  of the cutting tip  23  is moved toward the supporting surface  39 . 
   The force transmitting element  49  can be a ball, such as a ball bearing. Ordinarily, there will be a plurality of balls  49 . To install the ball  49  in the external groove  29  of the cutting tip  23  and the internal groove  47  of the sleeve arrangement  41 , the sleeve arrangement can include an opening  67  (shown in phantom in  FIG. 4A ) extending radially from an exterior axially extending surface  69  of the outer sleeve portion  51  to the internal groove  47  of the sleeve arrangement and through which the ball is adapted to pass. A plug member  71  (shown in phantom in  FIG. 4A ) such as a set screw can be provided for plugging the sleeve arrangement opening  67 . To assemble the cutting tip  23  and the sleeve arrangement  41 , the plug member  71  can be removed and the shank end  27  of the cutting tip can be inserted into the internal axially extending opening  35  of the cutting tip holder  33  until the external groove  29  and the internal groove  47  are substantially aligned. The ball(s)  49  can be inserted into the volume defined by the external groove  29  and the internal groove  47  through the radial opening  67  in the outer sleeve portion  51 . The plug member  71  can then be reinstalled in the radial opening  67  so that the ball(s)  49  cannot fall out of the volume defined by the external groove  29  and the internal groove  47 . 
   Once the force transmitting element(s)  49  are disposed in the internal groove  47  of the outer sleeve portion  51  of the sleeve arrangement  41 , the radially extending opening(s)  59  in the inner sleeve portion  57 , and the external groove  29  of the shank end  27  of the cutting tip  23 , then relative axial movement of the cutting tip and the outer and inner sleeve portions is limited as a function of the size of the internal and external grooves and the force transmitting element(s). The force transmitting element(s)  49  can be held at desired angular orientations relative to one another in the radially extending opening(s)  59  in the inner sleeve portion  57 . In this way, axial force transmission between the shank end  27  of the cutting tip  23  and the outer sleeve portion  51  can be distributed evenly around the external groove  29  and the internal groove  47 . 
   The externally threaded member  45 , together with the outer sleeve portion  51  to which it is attached as well as the inner sleeve portion  57  and the cutting tip  23  that are secured to the outer sleeve portion by the force transmitting element(s), is placed in the internal axially extending portion  39  of the internal axially extending opening  35  of the cutting tip holder. Threads on the externally threaded member  45  are caused to engage with the internally threaded portion  39  of the internal axially extending opening  35  of the cutting tip holder  33  and the externally threaded member is turned in a rotational direction opposite the direction in which the tool  21  is intended to rotate during operation so that threads of the externally threaded member engage threads of the internally threaded portion  39  to a desired extent. As the externally threaded member  45  is rotated relative to the internally threaded portion  39  and, therefore, moves downward relative to the cutting tip holder  33 , the outer sleeve portion  51  moves downward and an upper portion  47   u  of the internal groove  47  contacts the force transmitting element(s)  49 , see  FIG. 1C . As the externally threaded member  45  is further rotated relative to the internally threaded portion  39 , the force transmitting element(s)  49  contact the bottom portion(s)  59   b  of the radially extending opening through the inner sleeve portion  57  to cause the second abutment surface  63  to move toward the second supporting surface  65 . As the externally threaded member  45  is further rotated relative to the internally threaded portion  39 , the force transmitting element(s)  49  contact the bottom portion  29   b  of the external groove  29  which functions as an axial force bearing surface so that the abutment surface  31  of the cutting tip  23  moves toward the supporting surface  37  of the cutting tip holder  33 . The cutting tip  23  will ordinarily be properly positioned relative to the cutting tip holder  33  when the second abutment surface  63  contacts the second supporting surface  65  and the abutment surface  31  contacts the supporting surface  37 . 
     FIGS. 6 and 7  show another embodiment of a tool  121  that can have a replaceable working portion. The tool  121  is a cutting tool, although the present invention has applications in areas other than in cutting tools with replaceable working portions. The tool  121  can include a cutting tip  123 . The cutting tip  123  can include a working end  125  and a connecting end or shank end  127 . The shank end  127  has an external groove  129  therein. The external groove  129  can be, but need not be, a circumferential groove extending around the entire circumference of the shank end  127 . The cutting tip  123  also includes a radially extending abutment surface  131  between the working end  125  and the shank end  127 . 
   The tool  121  can also include a cutting tip holder  133 . The cutting tip holder  133  includes an internal axially extending opening  135  for receiving the shank end  127  and a radially extending supporting surface  137  for abutting against the abutment surface  131  of the cutting tip  123  to limit axial movement of the cutting tip relative to the cutting tip holder. The distance between the abutment surface  131  and the distal tip of the working end  125  is ordinarily precisely controlled to ensure that the cutting edge(s) of the working end are located where they are intended to be located. The internal axially extending opening  135  includes an internally threaded portion  139 . 
   The tool  121  can also include a sleeve arrangement  141  disposed between the shank end  127  and an internal surface  143  of the internal axially extending opening  135 . The sleeve arrangement  141  includes an externally threaded member  145  adapted to engage the internally threaded portion  139  of the cutting tip holder  133 . The sleeve arrangement  141  is adapted to engage the external groove  129  and move the cutting tip  123  such that the abutment surface  131  of the cutting tip moves toward the supporting surface  137  of the cutting tip holder  133  when the externally threaded member  145  is rotated relative to the cutting tip holder. 
   The sleeve arrangement  141  includes a compressible sleeve portion  147  disposed between the internal surface  143  of the internal axially extending opening  135  of the cutting tip holder  133  and the external groove  129  of the cutting tip  123 . The external groove  129  includes a frustoconical surface  149  having a smallest diameter d closer to the working end  125  of the cutting tip  123  than a largest diameter D. An upper end  151  of the compressible sleeve portion  147  is bounded by a radially extending flange portion  153  of the cutting tip holder  133 . Rotation of the externally threaded member  145  in a direction opposite to a direction of rotation of the tool  121  during operation compresses the compressible sleeve portion  147  against the frustoconical surface  149  of the external groove  129  of the cutting tip  123  such that a force F in an axial direction is applied to the frustoconical surface which functions as an axial force bearing surface. 
   The externally threaded member  145  can include a second radially extending abutment surface  155  and the internal axially extending opening  135  of the cutting tip holder  133  can include a second radially extending supporting surface  157  for abutting the second radially extending abutment surface and preventing further compression of the compressible sleeve portion  147 . 
   The sleeve arrangement  141  may also include a sleeve portion  159  disposed around part of the shank end  127  and disposed axially between the compressible sleeve portion  147  and the externally threaded member  145 . The sleeve portion  159  may be incompressible or compressible. 
   The compressible sleeve portion  147  can be any suitable compressible material. The compressible material may include an elastomeric material. The compressible material may be a bag including a non-sticking material such as TEFLON and having a plurality of balls or pellets of compressible or incompressible material disposed inside of the bag. 
   Thus far, embodiments have been described wherein a male connecting or shank end of a tool tip is received in a female mating end or opening of a tip holder. The invention is not limited to such embodiments, which are merely illustrative. For example,  FIG. 8  shows another embodiment wherein a tip holder  233  has a mating end  235  that is adapted to be received in a female connecting end  227  of a tip  223  with a working end  225 . In the embodiment of  FIG. 8 , the mating end  235  of the tip holder  233  can include a connecting rod  241  that can have an external groove  247  proximate one end and an externally threaded portion  245  proximate another end. The rod  241  can also have a non-circular opening  261   a  for receiving a tool for turning the rod. The tip holder  233  can have an axially extending opening that can have an internally threaded portion  239  for mating with the externally threaded portion  245  of the connecting rod  241 . The connecting end  227  of the tip  223  can be provided with one or more radial openings  267  that can be closed with, e.g., a plug  271  to define a groove  229  to retain a member such as a ball  249  that can be partially received in the external groove  247  of the connecting rod  241 . The mating end  227  can include a non-circular internal opening portion  262  that receives a non-circular external portion  261  of the connecting rod  241  such that the tip  223  is non-rotatable relative to the connecting rod. 
   When the connecting rod  241  is turned in a retaining direction relative to the tip holder  233  by a tool received in the non-circular opening  261   a , the external groove  247  on the connecting rod moves toward the tip holder. The ball  249  contacts the top of the external groove  247  and the bottom of the groove  229  so that the tip  223  is drawn toward the tip holder  233  until an abutment surface  231  on the tip contacts a supporting surface  237  on the tip holder. 
   It should be noted that in all described embodiments according to the present invention the tip can alternatively be gripped by a tool such as a wrench to secure the tip to the tip holder by means of relative rotation. 
   In the present application, the use of terms such as “including” is open-ended and is intended to have the same meaning as terms such as “comprising” and not preclude the presence of other structure, material, or acts. Similarly, though the use of terms such as “can” or “may” is intended to be open-ended and to reflect that structure, material, or acts are not necessary, the failure to use such terms is not intended to reflect that structure, material, or acts are essential. To the extent that structure, material, or acts are presently considered to be essential, they are identified as such. 
   While this invention has been illustrated and described in accordance with a preferred embodiment, it is recognized that variations and changes may be made therein without departing from the invention as set forth in the claims.