Cutting bit and extraction tool for same

Abstract

A cutting bit for a bit assembly secured to a cutter head includes a cutting end, a shank extending along a bit axis, and a shoulder positioned between the cutting end and the shank. The shoulder includes an outer edge defining a perimeter, a shoulder end surface defining a shoulder plane, a first inclined surface and a second inclined surface. The first inclined surface is positioned between the outer edge and the shoulder end surface. The first inclined surface extends along the perimeter and is oriented at a first acute angle relative to the shoulder plane. The second inclined surface is positioned between the shoulder end surface and the first inclined surface. The second inclined surface is oriented at a second acute angle relative to the shoulder plane, and the second acute angle is smaller than the first acute angle.

What is claimed is: 
     
         1 . An extraction tool for removing a portion of a cutting bit assembly of a cutter head, the cutting bit assembly including a bit having a shoulder end surface abutting an end surface of one of a sleeve and a bit holder, the extraction tool comprising:
 a shaft including a first end and a second end;   a head coupled to the second end of the shaft, the head including a body and a pair of fingers extending away from the body, the body including a face end surface, each of the fingers including a base end connected to the body and a distal end positioned away from the body, the fingers spaced apart from one another by a gap, a groove formed between the base ends of the fingers, a plane positioned laterally between the fingers such that one of the fingers is positioned on one side of the plane and the other finger is positioned on the other side of the plane, each finger further including an upper surface and an inclined surface,   wherein the inclined surface extends at least partially between the distal end and the base end, the inclined surface tapering inwardly toward the plane such that a first distance between the inclined surface and the plane proximate the distal end is greater than a second distance between the inclined surface and the plane proximate the groove,   wherein the inclined surface also tapers inwardly toward the plane from the upper surface such that a first offset distance between an upper edge of the inclined surface and the plane is greater than a second offset distance between a lower edge of the inclined surface and the plane.   
     
     
         2 . The extraction tool of  claim 1 , wherein each finger includes a lower surface oriented perpendicular to the plane, the upper surface of each finger is inclined relative to the lower surface such that a first height between the upper surface and the lower surface proximate the base end is larger than a second height between the upper surface and the lower surface proximate the distal end. 
     
     
         3 . The extraction tool of  claim 1 , wherein the inclined surface forms a first angle relative to the upper surface of between approximately 5 degrees and approximately 30 degrees. 
     
     
         4 . The extraction tool of  claim 3 , wherein the first angle is between approximately 10 degrees and approximately 25 degrees. 
     
     
         5 . The extraction tool of  claim 4 , wherein the first angle is between approximately 10 degrees and approximately 15 degrees. 
     
     
         6 . The extraction tool of  claim 5 , wherein the first angle is approximately 13 degrees. 
     
     
         7 . The extraction tool of  claim 1 , wherein the inclined surface extends along an axis between the distal end and the base end, the axis forming a second angle relative to the plane of between approximately 2 degrees and approximately 20 degrees. 
     
     
         8 . The extraction tool of  claim 7 , wherein the second angle is between approximately 5 degrees and approximately 10 degrees. 
     
     
         9 . The extraction tool of  claim 8 , wherein the second angle is approximately 6 degrees. 
     
     
         10 . An extraction tool for removing a portion of a cutting bit assembly of a cutter head, the cutting bit assembly including a bit having an end surface abutting an end surface of one of a sleeve and a bit holder, the extraction tool comprising:
 a shaft including a first end and a second end;   a head coupled to the second end of the shaft, the head including
 a body including a first end and a second end, the first end including an end surface, and 
 a pair of fingers extending away from the body, each of the fingers including a base end and a distal end, the base end of each of the fingers connected to the second end of the body, the distal end positioned away from the body, the fingers spaced apart from one another by a gap, each of the fingers further including an upper surface oriented along an inclined plane such that a first thickness of the finger proximate the base end is larger than a second thickness of the finger proximate the distal end, each of the fingers further including a wedge surface positioned proximate the upper surface and proximate the gap, each wedge surface extending at least partially between the distal end and the base end of the associated finger, each wedge surface tapering inwardly from the upper surface of the associated finger toward a lower surface the other finger, a distance between the wedge surfaces proximate the upper surfaces being greater than a distance between the wedge surfaces proximate the lower surfaces. 
   
     
     
         11 . The extraction tool of  claim 10 , wherein each wedge surface tapers inwardly toward one another such that a distance between the wedge surfaces proximate the distal ends of the fingers is greater than a distance between the wedge surfaces proximate the base ends of the fingers. 
     
     
         12 . The extraction tool of  claim 10 , wherein each of the fingers includes an inner surface positioned proximate the plane, the inner surfaces tapering toward one another, a first distance between the inner surfaces proximate the distal ends of the fingers being greater than a second distance between the inner surfaces proximate the base ends of the fingers. 
     
     
         13 . The extraction tool of  claim 12 , wherein a plane is positioned laterally between the fingers, one of the fingers positioned on one side of the plane and the other finger positioned on the other side of the plane, wherein each of the inner surfaces is oriented at a lateral angle relative to the plane, the lateral angle being between approximately 2 degrees and approximately 20 degrees. 
     
     
         14 . The extraction tool of  claim 13 , wherein the lateral angle is between approximately 5 degrees and approximately 10 degrees. 
     
     
         15 . The extraction tool of  claim 14 , wherein the lateral angle is approximately 6 degrees. 
     
     
         16 . The extraction tool of  claim 10 , wherein each wedge surface is oriented at a first angle relative to the upper surface of the associated finger, the first angle being between approximately 5 degrees and approximately 30 degrees. 
     
     
         17 . The extraction tool of  claim 13 , wherein the first angle is between approximately 10 degrees and approximately 25 degrees. 
     
     
         18 . The extraction tool of  claim 14 , wherein the first angle is between approximately 10 degrees and approximately 15 degrees. 
     
     
         19 . The extraction tool of  claim 15 , wherein the first angle is approximately 13 degrees. 
     
     
         20 . The extraction tool of  claim 10 , wherein the upper surface forms a plane oriented at an inclination angle relative to the lower surface, the inclination angle being between approximately 10 degrees and approximately 30 degrees. 
     
     
         21 . A method of extracting a portion of a cutting bit assembly from one of a sleeve and a bit holder, the method comprising:
 positioning an extraction tool against an engagement surface of the portion of the cutting bit assembly, the extraction tool including a pair of fingers spaced apart by a gap, the portion of the cutting bit assembly positioned in the gap, each finger including an upper surface, an inner surface proximate the gap, and a wedge surface positioned between the inner surface and the upper surface, the upper surface extending along a plane oriented at an angle relative to a lower surface, the wedge surface extending in a plane oriented at an angle relative to the upper surface; and   applying a force on the extraction tool to exert pressure against the engagement surface of the portion of the cutting bit.   
     
     
         22 . The method of  claim 21 , wherein applying the force includes applying an impact force against an end surface of a head of the extraction tool.