Drill Rod

Abstract

A single-piece hollow percussive drill rod is specifically adapted for percussive drilling. The drill rod has a main body, a working end and a collar. The working end has a thread for receiving a percussive drill bit. The collar is positioned between the thread and the main body, the collar also being upset forged. A method of manufacturing a single-piece hollow drill rod specifically adapted for percussive drilling is also disclosed.

1 . A single-piece hollow percussive drill rod specifically adapted for percussive drilling, the drill rod having a main body, a working end having a thread for receiving a percussive drill bit, and a collar between said thread and said main body, wherein the collar is upset forged. 
     
     
         2 . The drill rod of  claim 1 , in which the collar is positioned in relation to the thread such that a drill bit, when fitted, engages with both the thread and the collar. 
     
     
         3 . The drill rod of  claim 1 , in which the thread has an axis, and the collar is comprised of a shoulder feature having an annular face angled 80 to 110 degrees from the axis of the thread. 
     
     
         4 . The drill rod of  claim 1 , in which the collar is a half-ball collar. 
     
     
         5 . The drill rod of  claim 1 , in which the main body has a geometric cross-section which is one of:
 cylindrical   square;   hexagonal; and   octagonal.   
     
     
         6 . The drill rod of  claim 1 , in which the thread form is one of:
 cylindrical; and   conical.   
     
     
         7 . The drill rod of  claim 1 , further comprising one of an additional thread and a shank of geometric cross-section at an end of the main body which is opposite to the thread. 
     
     
         8 . A single-piece hollow drill rod having a flushing hole therethrough, the drill rod having a main body, a working end having a thread for receiving a drill bit, and a collar between said thread and said main body, wherein the collar is upset forged and the flushing hole is less than 10 millimetres in diameter. 
     
     
         9 . The drill rod of  claim 8 , in which the collar is positioned in relation to the thread such that a drill bit, when fitted, engages with both the thread and the collar. 
     
     
         10 . The drill rod of  claim 8 , in which the thread has an axis, and the collar is comprised of a shoulder feature angled 80 to 110 degrees from the axis of the thread. 
     
     
         11 . The drill rod of  claim 8 , in which the collar is a half-ball collar. 
     
     
         12 . The drill rod of  claim 8 , in which the main body has a cross-section which is one of:
 circular;   square;   hexagonal; and   octagonal.   
     
     
         13 . The drill rod of  claim 8 , in which the thread form is one of:
 cylindrical; and   conical.   
     
     
         14 . The drill rod of  claim 8 , further comprising one of an additional thread and a shank of geometric cross-section at an end of the main body which is opposite to the thread. 
     
     
         15 . A method of manufacturing a single-piece hollow drill rod specifically adapted for percussive drilling, in which a bar of hollow drill steel is forged, comprising the steps of:
 heating a working end of the drill steel to a forging temperature;   upset forging a collar on the working end of the drill steel; and   machining a thread on the working end of the drill steel for receiving a drill bit such that said collar is positioned between said thread and a main body of said drill rod.   
     
     
         16 . The method of  claim 15 , in which the step of heating includes the step of using one of a high-frequency induction coil and a furnace heat source to heat the working end of the drill steel prior to forging. 
     
     
         17 . The method of  claim 15 , further comprising a step of heat treating the drill rod after machining.