Patent ID: 8960336
Filing Date: 2015-02-24
Classification: B23B,E21B,Y10T

Abstract:
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.