ROCK DRILL BIT AND A ROCK DRILLING TOOL

摘要

A rock drill bit for percussive drilling comprising a head portion (1) with a front surface which has a number of inserts (7) provided in a peripheral ring, and a number of front inserts (9, 10) placed radially inside the peripheral inserts. At least a first surface portion (4) is provided on the front surface, which is recessed at a certain depth in relation to a surrounding second surface portion (5). One or more channels (12) for feed of flush medium to cool inserts and convey away drill cuttings between the drill bit and a bore wall terminates in the front surface. The second surface portion (5) is a part of an endless land portion which delimits and wholly surrounds the recessed space in connection to the first surface portion (4) in order to always retain a cushion of flush medium in this space for the purpose of flushing in a versatile manner and cooling said from inserts (9, 10). The present invention also relates to a rock-drilling tool for percussive drilling.