Modular drilling system

Abstract

A modular drilling system including a plurality of different size drill bits which can be interchangeably mounted on a common tapered male connecting portion of a drill rod assembly. The tapered male connecting portion may be formed directly onto a tapered drill rod of the assembly or may be formed on an adapter which is threaded onto a threaded drill rod of the assembly. Each bit includes a female connecting portion having a generally cylindrical tapered surface mating with a corresponding tapered surface of the male connecting portion and at least three planar sections adapted to provide positive engagement with corresponding planar sections of the male connecting portion.

1 . A drill bit for use with a male connecting portion of a drill rod assembly, the drill bit comprising:
 a body extending in a longitudinal direction between a bit face at a forward end and a female connecting portion at a rear end;   the female connecting portion defining a socket comprising:
 a generally cylindrical tapered surface adapted to form a mating connection with a corresponding tapered surface of the male connecting portion; and 
 at least three planar sections formed on the tapered surface at evenly spaced apart positions in a circumferential direction about the socket so as to be adapted to provide positive engagement with corresponding planar sections of the male connecting portion. 
   
     
     
         2 . The drill bit according to  claim 1  in combination with a plurality of auxiliary bits, each having a bit face at a forward end and a female connecting portion at a rear end which is substantially identical to the female connecting portion of said drill bit, the bit faces of the plurality of auxiliary bits being different in size relative to one another. 
     
     
         3 . The drill bit according to  claim 1  in combination with a drill rod of the drill rod assembly, the male connecting portion being defined on drill rod so as to comprise:
 a generally cylindrical tapered surface adapted to mate with the corresponding tapered surface of the female connecting portion; and 
 a planar section formed on the tapered surface in mating alignment with each of the planar sections of the female connecting portion. 
 
     
     
         4 . The drill bit according to  claim 1  in combination with an adapter having a rear end adapted to be supported on a drill rod of the drill rod assembly, the male connecting portion being defined on a forward end of the adapter so as to comprise:
 a generally cylindrical tapered surface adapted to mate with the corresponding tapered surface of the female connecting portion; and 
 a planar section formed on the tapered surface in mating alignment with each of the planar sections of the female connecting portion. 
 
     
     
         5 . The drill bit according to  claim 4  wherein the rear end of the adapter comprises a female connecting portion formed with an internal thread adapted to engage in screw-threaded engagement with the male connecting portion of a threaded drill rod. 
     
     
         6 . The drill bit according to  claim 1  wherein a surface area of said at least three planar sections is at least 35% of a total surface area of the generally cylindrical tapered surface locating the planar sections thereon. 
     
     
         7 . The drill bit according to  claim 1  wherein each planar section extends substantially a full length of the tapered female connecting portion. 
     
     
         8 . The drill bit according to  claim 1  wherein the generally cylindrical tapered surface is oriented at a first inclination to a longitudinal axis of the drill bit and the planar sections are oriented at a second inclination to the longitudinal axis of the drill bit which is greater than the first inclination. 
     
     
         9 . The drill bit according to  claim 8  wherein a width of each planar section generally in the circumferential direction is reduced from the front end to the rear end of the drill bit. 
     
     
         10 . The drill bit according to  claim 8  wherein the first inclination is less than 10 degrees and the second inclination is within 3 degrees of the first inclination. 
     
     
         11 . The drill bit according to  claim 10  wherein the second inclination differs by approximately one degree from the first inclination. 
     
     
         12 . The drill bit according to  claim 10  wherein the first inclination is approximately 5 degrees and the second inclination is approximately 6 degrees. 
     
     
         13 . The drill bit according to  claim 1  in combination with a male connecting portion comprising a generally cylindrical tapered surface adapted to mate with the corresponding tapered surface of the female connecting portion, a planar section formed on the tapered surface in mating alignment with each of the planar sections of the female connecting portion, and an outer end face at a forward end,
 wherein the socket of the female connection portion comprises an internal end face and the planar sections are oriented relative to the internal end face such that:
 the internal end face is adapted to be spaced from the outer end face of the male connecting portion when the planar sections of the female connecting portion initially abut the planar sections of the male connecting portion; and 
 the internal end face is adapted to positively engage the outer end face of the male connecting portion when the drill bit is subjected to percussion drilling forces from the drill rod assembly. 
 
 
     
     
         14 . The drill bit according to  claim 1  in combination with a male connecting portion comprising a generally cylindrical tapered surface adapted to mate with the corresponding tapered surface of the female connecting portion, and a planar section formed on the tapered surface in mating alignment with each of the planar sections of the female connecting portion, wherein the male connecting portion is further integrally connected to a body portion formed at the rear end of the male connecting portion and having a greater diameter than the male connecting portion so as to define an annular shoulder about a rear end of the male connecting portion. 
     
     
         15 . The drill bit according to  claim 14  wherein the socket of the female connection portion comprises annular end face at the rear end and the planar sections are oriented relative to the annular end face such that:
 the annular end face is adapted to be spaced from the annular shoulder of the male connecting portion when the planar sections of the female connecting portion initially abut the planar sections of the male connecting portion; and 
 the annular end face is adapted to positively engage the annular shoulder of the male connecting portion when the drill bit is subjected to percussion drilling forces from the drill rod assembly. 
 
     
     
         16 . The drill bit according to  claim 1  in combination with an adapter having a rear end adapted to be supported on a drill rod of the drill rod assembly, the male connecting portion being defined on a forward end of the adapter, and the body of the adapter being formed of a material having a greater hardness than the drill bit. 
     
     
         17 . The drill bit according to  claim 1  wherein the bit face comprises a plurality of protrusions of material having a greater hardness than the body of the drill bit, the protrusions being radially and circumferentially spaced from one another. 
     
     
         18 . A modular drilling system for use with a male connecting portion of a drill rod assembly, the system comprising:
 a plurality of drill bits, each having a body extending in a longitudinal direction between a bit face at a forward end and a female connecting portion at a rear end;   the female connecting portion of each drill bit defining a socket comprising:
 a generally cylindrical tapered surface adapted to form a mating connection with a corresponding tapered surface of the male connecting portion; and 
 at least three planar sections formed on the tapered surface at evenly spaced apart positions in a circumferential direction about the socket so as to be adapted to provide positive engagement with corresponding planar sections of the male connecting portion; 
   the female connecting portions of the drill bits being substantially identical to one another; and   the bit faces of the plurality of auxiliary bits being different in size relative to one another.   
     
     
         19 . The system according to  claim 18  in combination with a common male connecting portion comprising:
 a generally cylindrical tapered surface adapted to mate with the corresponding tapered surface of the female connecting portion of each drill bit; and 
 a planar section formed on the tapered surface in mating alignment with each of the planar sections of the female connecting portion of each drill bit. 
 
     
     
         20 . A modular drilling system for use with a male connecting portion of a drill rod assembly, the system comprising:
 an adapter having a rear end comprising a female connecting portion formed with an internal thread so as to be adapted to engage in screw-threaded engagement with a male portion of a threaded drill rod of the drill rod assembly and a forward end defining a common male connecting portion comprising:
 a generally cylindrical tapered surface; and 
 at least three planar sections formed on the tapered surface at evenly spaced apart positions in a circumferential direction; and 
   a plurality of drill bits, each having a body extending in a longitudinal direction between a bit face at a forward end and a female connecting portion at a rear end, the bit faces of the plurality of auxiliary bits being different in size relative to one another, and the female connecting portion of each drill bit defining a socket comprising:
 a generally cylindrical tapered surface adapted to form a mating connection with the corresponding tapered surface of the common male connecting portion of the adapter; and 
 a planar section formed on the tapered surface of the female connecting portion in alignment with each of the planar sections of the male connecting portion of the adapter so as to be adapted to provide positive engagement of the planar sections of the drill bit with the corresponding planar sections of the male connecting portion of the adapter.