Rock drill bit

摘要

A rock drill bit having a shank fitted with a clamping end and a drilling tip located from the clamping end. The drilling tip has at least three blades and a central zone centered on a drill bit axis. The blades each include on a top side thereof a lip constituted by a leading chipping face and a trailing flank. The lips substantially converge onto each other within a the central zone of the drilling tip, wherein in the central zone, a long lip of the lips runs through the drill bit axis and has a commensurate overshoot segment extending beyond the drill bit axis.

主权项

1. A rock drill bit comprising:
a shank fitted with a clamping end and a drilling tip at the end away from the clamping end, wherein the drilling tip comprises at least three blades curved relative to the cutting direction of rotation of the rock drill bit such that they are alar in topview, said blades each comprise, at their top side a lip constituted by a leading chipping face and a trailing flank, the lips substantially converging onto each other within a central zone centered on the drill bit axis, in the central zone, a single lip that is long runs through the drill bit axis and comprises a commensurate overshoot segment extending beyond the drill bit axis, and in the vicinity of the drill bit axis, the long lip constitutes a chisel edge, wherein said chisel edge has an edge profile different from that of another portion of the long lip and said chisel edge comprises two radially outer ends axially projecting from the in-between center of said chisel edge.