Modular drill with enhanced bump-off capability

Abstract

A rotary cutting tool with enhanced bump-off capability is disclosed. The cutting tool includes a tool shank having a pocket. A replaceable cutting head is at least partially disposed within the pocket of the tool shank with an interference fit. A coupling pin assembly is at least partially received within a bore of the tool shank. The coupling pin assembly comprises a sleeve member and a coupling pin at least partially disposed within the sleeve member. The sleeve member includes an upper portion and a lower portion having a non-circular cross-sectional shape with a bump-off surface. An actuation screw contacts the coupling pin assembly and causes the replaceable cutting head to move relative to the tool shank. The bump-off surface of the lower portion of the sleeve member extends radially outward with respect to the coupling pin by a distance, D, thereby providing enhanced bump-off capability.

1 - 9 . (canceled) 
     
     
         10 . A modular drill with enhanced bump-off capability, comprising:
 a tool shank having a pocket with a central floor portion, and a bore extending downward from the central floor portion, the bore having an upper portion and a reduced-diameter lower portion;   a replaceable cutting head at least partially disposed within the pocket of the tool shank with an interference fit, the replaceable cutting head including a bore with a threaded upper portion and a non-threaded lower portion;   a coupling pin assembly comprising a sleeve member and a coupling pin at least partially disposed within the sleeve member, the sleeve member including an upper portion capable of being received in the non-threaded lower portion of the replaceable cutting head, the sleeve member further including a lower portion extending radially outward with respect to the upper portion and having a non-circular cross-sectional shape with a bump-off surface, the lower portion of the sleeve member capable of being received in the upper portion of the bore of the tool shank, the coupling pin including an upper portion with a threaded portion capable of being received in the threaded upper portion of the replaceable cutting head, the coupling pin further including a lower portion configured to make partial contact with the reduced-diameter lower portion of the bore of the tool shank; and   an actuation screw for contacting the coupling pin assembly and causing the replaceable cutting head to move relative to the tool shank,   wherein the bump-off surface of the lower portion of the sleeve member extends radially outward with respect to the coupling pin by a distance, D, and contacts the actuation screw when moving the replaceable cutting insert from a clamped position to a bump-off position, thereby providing enhanced bump-off capability.   
     
     
         11 . The modular drill according to  claim 10 , wherein the non-circular lower portion of the sleeve member has a stadium cross-sectional shape. 
     
     
         12 . The modular drill according to  claim 10 , wherein the lower portion of the coupling pin includes a recess having an upper surface and a lower clamping surface for contacting the actuation screw when placing the replaceable cutting head in the clamped position. 
     
     
         13 . The modular drill according to  claim 12 , wherein the actuation screw has a threaded upper portion and a non-threaded lower portion. 
     
     
         14 . The modular drill according to  claim 13 , wherein the non-threaded lower portion of the actuation screw includes a neck region defined by an upper conical surface, a lower conical surface, a reduced-diameter surface and a bottom surface. 
     
     
         15 . The modular drill according to  claim 14 , wherein the bottom surface of the actuation screw contacts the clamping surface of the coupling pin when place the replaceable cutting head in the clamped position. 
     
     
         16 . The modular drill according to  claim 10 , wherein the bump-off surface is non-planar. 
     
     
         17 . The modular drill according to  claim 16 , wherein the bump-off surface is convex-shaped. 
     
     
         18 . A method for a rotary cutting tool with enhanced bump-off capability, the rotary cutting tool comprising a tool shank; a replaceable cutting head; a coupling pin assembly at least partially received within a bore of the tool shank, the coupling pin assembly comprising a sleeve member and a coupling pin at least partially disposed within the sleeve member, the sleeve member including an upper portion and a lower portion having a non-circular cross-sectional shape with a bump-off surface extending radially outward with respect to the coupling pin by a distance, D; and an actuation screw for contacting the coupling pin assembly and causing the replaceable cutting head to move relative to the tool shank, the method comprising:
 rotating the actuation screw in a first direction until a portion of the actuation screw is disposed within the reduced-diameter lower portion of the bore of the tool shank;   inserting the replaceable cutting head into a pocket of the tool shank until the replaceable cutting head contacts the actuation screw;   rotating the actuation screw in a second direction until the portion of the actuation screw is no longer disposed within the reduced-diameter lower portion of the bore of the tool shank, thereby causing the replaceable cutting head to move downward into the pocket and the sleeve member of the coupling pin assembly to contact the actuation screw; and   rotating the actuation screw in the first direction until the actuation screw contacts a contact surface of the coupling pin and placing the replaceable cutting head in a clamped position.   
     
     
         19 . The method according to  claim 18 , further comprising the steps of:
 rotating the actuation screw in the second direction until the actuation screw contacts the bump-off surface of the sleeve member to place the replaceable cutting head in a bump-off position.   
     
     
         20 . The method according to  claim 19 , further comprising the step of:
 rotating the actuation screw in the second direction until the actuation screw no longer contacts the bump-off surface of the sleeve member to place the replaceable cutting head in a removal position.   
     
     
         21 . The modular drill according to  claim 10 , wherein an outer ledge is formed at an intersection between the upper portion of the sleeve member and the lower portion of the sleeve member. 
     
     
         22 . The modular drill according to  claim 10 , wherein a ratio between the distance, D, and a cutting diameter of the replaceable cutting head is between about 0.02 and about 0.12. 
     
     
         23 . The modular drill according to  claim 10 , wherein the lower portion of the sleeve member has a bottom surface, and wherein the bump-off surface is located on the bottom surface of the sleeve member.