A ROCK DRILL BIT, A DRILLING ASSEMBLY AND A METHOD FOR PERCUSSIVE ROCK DRILLING

摘要

A rock drill bit for percussive drilling comprising a bit head (21) configured to be attached at an end of a drill element of a drilling as- sembly and having a diameter larger than that of a said drill element. 5 The bit head has at a front end (23) as seen in the intended drilling direction a generally frusto-conical shape defined by a substantially circumferential ring (24) provided with a plurality of gauge buttons (25) distributed along the extension of the ring for engaging material to be crushed. A central flush channel (29) extends through the bit 10 head and has at least one flushing hole (32-35) opening at said front end to conduct flushing medium to said front end. At least one peripheral flushing hole (32-34) of said at least one flushing hole (32-35) opening at said front end opens in said substantially circumferential ring (24). At least two peripheral flushing holes (32-15 34) open in said substantially circumferential ring (24).