Rotatable point-attack bit with protective body

Abstract

A rotatable point-attack bit retained for rotation in a block bore, and used for impacting, fragmenting and removing material from a mine wall. An improved elongated tool body having at the front end a diamond-coated tungsten carbide wear tip that is rotationally symmetric about its longitudinal axis and contiguous with a protective tungsten carbide intermediary body, which is contiguous with the third section steel shank at the rear end.

What I claim as my invention is:  
     
         1 . A rotatable cutting bit for impacting, fragmenting and removing a substrate comprising of: 
 a ferrous body or shank having a longitudinal axis and forward end;    a protective cemented carbide mid section body rotationally symmetric about said longitudinal axis;    a diamond coated cemented carbide insert rotationally symmetric about said longitudinal axis.    
     
     
         2 . The rotatable cutting tool of  claim 1  wherein the forward end of the protective body contains a seat or radiused socket defining a volume.  
     
     
         3 . The rotatable cutting tool of  claim 1  wherein the axially rearward section of the insert has a protruding segment that generally corresponds to, and fits into, the shape of the seat or radiused socket of the protective body.  
     
     
         4 . A braze joint joining the protruding or radiused extension axially rearward section of the insert of  claim 1  to the mating seat or radiused socket of the axially forward section of the protective body.  
     
     
         5 . The rotatable cutting tool of  claim 1  wherein the steel third section of the tool body contains at its forward point a seat or radiused socket defining a volume.  
     
     
         6 . The rotatable cutting tool of  claim 1  wherein the protruding shape at the base of the protective body corresponds to the shape of the seat or radiused socket defined in  claim 5 .  
     
     
         7 . The rotatable cutting tool of  claim 1  wherein said protective body is affixed to the pocket of the steel shank of  claim 5  by brazing.  
     
     
         8 . A rotatable cutting bit for impacting, fragmenting and removing a substrate comprising of: 
 a ferrous body or shank having a longitudinal axis and forward end;    a protective cemented carbide mid section body rotationally symmetric about said longitudinal axis;    a diamond coated cemented carbide insert rotationally symmetric about said longitudinal axis.    
     
     
         9 . The protective cemented carbide mid section body of  claim 8  having a forwardly facing socket extending forwardly therefrom by way of a continuous radius to the forward most point of said body;  
     
     
         10 . The first forwardly facing surface of the protective mid section and the mating rearwardly facing surface of the insert of  claim 8  are bonded by a brazed joint.  
     
     
         11 . The protective cemented carbide mid section body of  claim 8  having a frusto conical surface or surfaces leading from the front of the body, where it is attached to the insert, to the rear of the body, where it is attached to the steel shank. The resulting diameter at the rear of the body being larger than the diameter at the front of the body.  
     
     
         12 . The protective cemented carbide mid section body of  claim 8  having a second rearwardly facing surface with a first rearwardly radiused surface leading to the rearwardly facing surface.  
     
     
         13 . The protective cemented carbide mid section body of  claim 8  wherein a second rearwardly facing surface is located radially inside and rearward of the first radiused rear surface.  
     
     
         14 . The protective cemented carbide mid section body of  claim 8  wherein the first forwardly facing surface of the steel body and the secondly rearwardly facing surface of the protective cemented carbide mid section are bonded by a brazed joint.  
     
     
         15 . The steel shank of  claim 8  having a means for holding a loosely resilient retainer on the steel body that allows the cutter bit to rotate about its longitudinal axis in a mounting block.