ROCK DRILL BIT

摘要

A rock drill bit comprising a shank (1) fitted with a clamping end (2) and a drilling tip (3) at the end away from the clamping end, the drilling tip (3) comprising at least three, preferably exactly three blades (4, 5, 6) which are alar in topview, said blades each comprising at their top side a lip (7, 8, 9) constituted by a leading chipping face (7a, 8a, 9a) and a trailing f lank(76, 86, 96), the lips substantially converging onto each other within a central zone (10) centered on the drill bit axis (11), wherein, in the central zone (10), a single lip (7) - long lip - runs through the bit axis (11) and comprises a commensurate overshoot segment (12) extending beyond the bit axis (11).