Symmetrical bit for directional drilling tool

Abstract

A percussion drill bit for directional drilling tools. The drill bit comprises a head portion formed with an axially extending shank. The drill bit also comprises engagement means on the shank engageable with complementary engagement means formed on a drive chuck whereby rotational drive from the chuck may be transmitted to the shank. The head portion of the drill bit is formed with a plurality of slant faces arranged symmetrically about the head portion.

1 . A percussion drill bit for directional drilling tools comprising:
 a head portion formed with an axially extending shank   engagement means on the shank engageable with complementary engagement means formed on a drive chuck whereby rotational drive from the chuck may be transmitted to the shank;   characterised in that the head portion of the drill bit is formed with a plurality of slant faces arranged symmetrically about the head portion.   
     
     
         2 . The percussion drill bit of  claim 1 , wherein each of the slant faces comprises a substantially planar surface angled with respect to an elongate axis of the bit. 
     
     
         3 . The percussion drill bit of  claim 1 , wherein each of the slant faces comprises a plurality of contiguous planar surfaces and each of the planar surfaces is angled with respect to the elongate axis of the bit. 
     
     
         4 . The percussion drill bit of  claim 2 , wherein each of the planar surfaces is continuous. 
     
     
         5 . The percussion drill bit of  claim 2 , wherein each of the planar surfaces is non-continuous. 
     
     
         6 . The percussion drill bit of  claim 1 , wherein the head portion of the drill bit is formed with an odd number of slant faces. 
     
     
         7 . The percussion drill bit of  claim 6 , wherein the head portion of the drill bit is provided with three slant faces. 
     
     
         8 . The percussion drill bit of  claim 1 , wherein the slant faces are provided with a hard-wearing material to improve wear resistance. 
     
     
         9 . The percussion drill bit of  claim 8 , wherein the hard-wearing material is provided in the form of flat wear carbides. 
     
     
         10 . The percussion drill bit of  claim 1 , wherein the engagement means comprises a plurality of axially extending splines on the shank slideably engageable with complementary splines formed on the drive chuck. 
     
     
         11 . The percussion drill bit of  claim 10 , wherein the number of splines is an integer multiple of the number of slant faces provided on the bit. 
     
     
         12 . A directional drilling tool comprising a locator housing threadably connected to percussion hammer by means of a sub, and a percussion drill bit disposed at a forward end of the hammer, wherein the percussion drill bit is percussion drill bit as claimed in any one of the preceding claims. 
     
     
         13 - 14 . (canceled) 
     
     
         15 . The percussion drill bit of  claim 2 , wherein each of the slant faces comprises a plurality of contiguous planar surfaces and each of the planar surfaces is angled with respect to the elongate axis of the bit. 
     
     
         16 . The percussion drill bit of  claim 3 , wherein each of the planar surfaces is continuous. 
     
     
         17 . The percussion drill bit of  claim 3 , wherein each of the planar surfaces is non-continuous.