Modular kerfing drill bit

Abstract

A modular kerfing rock drilling bit ( 10 ) is presented. Drill bit ( 10 ) comprises a bit body ( 12 ) having a connection ( 14 ) for attachment to a drill string member. A base portion ( 16 ) below the connection ( 14 ) has an outer portion ( 18 ) and a bottom ( 20 ). Slots ( 22 ) are formed in the base portion ( 16 ). A cutter assembly ( 100 ) comprises a leg ( 110 ) insertable into the slot ( 22 ) of the bit body ( 16 ). A journal ( 126 ) extends angularly downward and inward from the leg ( 110 ) for bearing support of a cone ( 180 ) rotatably mounted on the journal ( 126 ). A plurality of cutters ( 182 ) extend outward from the surface of the cone ( 180 ). A kerfing segment ( 140 ) extends downward from the leg ( 110 ) beyond the cone ( 180 ). A plurality of kerf cutters ( 142 ) are attached to the bottom of the kerfing segment ( 140 ).

1 . A modular kerfing drill bit, comprising: 
 a bit body comprising; 
 a connection for attachment to a drill string member;  
 a base portion below the connection means, having an outside surface, and a bottom surface; and,  
 at least one slot formed in the base portion;  
   a cutter assembly comprising; 
 a leg insertable into the slot of the bit body;  
 a journal extending angularly downward and inward from the leg;  
 a cone rotatably mounted on the journal;  
 a plurality of cutters extending outward from the surface of the cone;  
 a kerfing segment extending downward from the leg; and,  
 a plurality of kerf cutters attached to the bottom of the kerfing segment.  
   
     
     
         2 . The modular kerfing drill bit of  claim 1 , further comprising: 
 a kerfing assembly comprising; 
 a leg insertable into the slot of the bit body;  
 a kerfing segment extending downward from the leg; and,  
 a plurality of kerf cutters attached to the bottom of the kerfing segment.  
   
     
     
         3 . The modular kerfing drill bit of  claim 1 , further comprising: 
 wherein each kerf cutter on a kerfing segment is located at a unique radial position.    
     
     
         4 . The modular kerfing drill bit of  claim 1 , further comprising: 
 wherein a kerfing segment contains kerf cutters located at radial positions substantially equal to the radial positions of the kerf cutters on another kerfing segment of another leg.    
     
     
         5 . The modular kerfing drill bit of  claim 1 , the leg further comprising: 
 a lead face and an opposite trailing face;    a back face and an opposite center face;    a transition face angularly disposed between the center face and the kerfing segment; and,    wherein the journal extends outward substantially perpendicular to the transition face.    
     
     
         6 . The modular kerfing drill bit of  claim 5 , the leg further comprising: 
 a contiguous mesh of flow channels and flow slots extending from the leg center face, to between the kerf cutter, and to the leg back face.    
     
     
         7 . The modular kerfing drill bit of  claim 6 , the contiguous mesh of flow channels and flow slots further comprising: 
 alternating vertically and horizontally oriented of flow channels and flow slots.    
     
     
         8 . A cutter assembly comprising; 
 a leg insertable into the slot of the bit body;    a journal extending angularly downward and inward from the leg;    a cone rotatably mounted on the journal;    a plurality of cutters extending outward from the surface of the cone;    a kerfing segment extending downward from the leg; and, a plurality of cutters attached to the bottom of the kerfing segment.    
     
     
         9 . A kerfing assembly comprising; 
 a leg insertable into the slot of the bit body;    a kerfing segment extending downward from the leg; and,    a plurality of cutters attached to the bottom of the kerfing segment.    
     
     
         10 . A modular kerfing drill bit, comprising: 
 a bit body comprising; 
 a connection for attachment to a drill string member;  
 a base portion below the connection means, having an outside surface, and a bottom surface; and,  
 a plurality of slots formed in the base portion;  
   a cutter assembly comprising; 
 a leg insertable into the slot of the bit body;  
 a journal extending angularly downward and inward from the leg;  
 a cone rotatably mounted on the journal;  
 a plurality of cutters extending outward from the surface of the cone;  
 a kerfing segment extending downward from the leg; and,  
 a plurality of cutters attached to the bottom of the kerfing segment; and,  
   a kerfing assembly comprising; 
 a leg insertable into the slot of the bit body;  
 a kerfing segment extending downward from the leg; and,  
 a plurality of kerf cutters attached to the bottom of the kerfing segment.