Segment for a core drill bit and method of manufacture

Abstract

A core drill bit segment ( 10 ) comprises an elongated member ( 12 ) having an upper end ( 14 ), a lower end ( 16 ), first side ( 18 ) and opposite second side ( 20 ). Attached to the lower end ( 16 ) is matrix ( 22 ). The matrix ( 22 ), while depending from the lower end ( 16 ) also extends upwardly toward the upper end ( 14 ) along first and second sides ( 18, 20 ) of the member ( 12 ). The lower end ( 16 ) is provided with a lip ( 24 ) that is turned upwardly to extend in front of the first side ( 18 ) to define a recess ( 26 ) for seating a lower edge of a drive sub ( 25 ).

1 . A segment for a core drill bit, the segment comprising at least: 
 an elongated member having an upper end, a lower end, a first side and an opposite second side,    said lower end of the member provided with a lip turned upwardly to extend in front of the first side of the member to define a recess for seating a lower edge of a drive sub; and    a matrix attached to said lower end and extending toward said upper end up said lip on an outside of said recess and along said second side of the member.    
     
     
         2 . A segment according to  claim 1  wherein said matrix includes a first side on the first side of the member and an opposite second side on the second side of the member and where for a lower portion of the matrix the first and second sides of the matrix are substantially parallel to each other and for an upper portion of the matrix the first and second sides of the matrix converge toward the first and second sides respectively of the member.  
     
     
         3 . The segment according to  claim 1  or  2  wherein the first side of the matrix converges so as to meet an upper edge of the lip.  
     
     
         4 . The segment according to any one of  claims 1  to  3  wherein the second side of the matrix converges toward the second side of the member at a first location above a trough of the recess.  
     
     
         5 . The segment according to any one of  claims 1  to  4  wherein the matrix includes gauging means on the second side for cutting an outer surface, said gauging means disposed between said trough and said first location.  
     
     
         6 . The segment according to any one of  claims 1  to  5  wherein the first side of the matrix commences to converge toward the first side of the member at a point above the lower end of the member.  
     
     
         7 . The segment according to any one of  claims 1  to  6  wherein the point at which the first side of the matrix commences to converge toward the member is below the trough of the recess.  
     
     
         8 . A method of manufacturing a bit segment for a core drill bit including the steps of: 
 forming a plurality of side by side members with mutually adjacent members joined by integrally formed webs, the members juxtaposed to form a cylinder like structure, each member having an upper end, a lower end, a first side and an opposite second side, with the cylinder like structure having a lower end defined by the lower ends of the members, and an upper end defined by the respective upper ends of the members;    forming a matrix at the lower end of the cylinder like structure;    configuring the matrix so that it extends across the lower end of the cylinder like structure and up the first and second sides of the members toward the upper ends of the members; and    fragmenting said cylinder like structure into separate segments each of which comprises a member with matrix attached at its lower end, the matrix extending toward the upper end of the member along the first and second sides of the member.    
     
     
         9 . A method according to  claim 8  further included the step of, for an NQ size core drill bit, forming said cylinder like structure with six side by side members.  
     
     
         10 . A method according to  claim 8  or  9  wherein said step of forming a plurality of side by side members includes machining a tubular blank to form said members.