Percussion Rock Drilling Bit with More Efficient Flushing

Abstract

A design of crown of drill bit for percussive rock drilling with big “V” shape front flushing grooves, small central “dead” area will reduce the repeatedly crushing of broken rock cuttings. It will not only improve the rate of penetration, but also decrease the hole deviation, as well as the erosion to the outer surface of drive sub and case tube of DTH hammer.

1 . A crown of rock drill bit for percussion rock drilling, comprising at least three fluid passages or flushing holes  1  which emerge in the vicinity of the front face  8  of the crown; each flushing hole connecting to a radially extending front groove  3  formed in the front face; the outer end of each front groove connecting to a side groove  6  which extend axially rearward; wherein each land formed between the grooves carries at least one gauge insert  2  and one front insert  9 . 
   
   
       2 . The bit crown, according to  claim 1  has only one button in the central area  5 , the area within the inner edge of the flushing holes/grooves of the front head. 
   
   
       3 . According to  claim 1 , the shape of each front groove  3 , when looking at the bit front face, is “V” shape, the width of the front grooves, when measuring across the center of the flushing hole, is bigger than its diameter, getting wider outwards, to minimum 1.3 times wider towards the outer edge  7  of bit front head. 
   
   
       4 . According to  claim 3 , the sides  3   a  and  3   b  of front grooves  3 , when looking at the bit front face  8 , can be straight and/or curved; the opening width of side grooves  6  is the same or bigger than that of front grooves  3 .