Patent ID: 11866997

Abstract:
A rotary percussive hydraulic drill comprises a body; a shank having female coupling splines and male coupling splines; a striking piston configured to strike the shank; a rotation drive device configured to drive the shank in rotation; a front abutment surface against which the shank is configured to come into abutment. The shank has an annular bearing flange which is provided on an outer surface of the shank and which has an annular bearing surface configured to come into abutment against the front abutment surface. Each of the female and male coupling splines provided on the shank extends from the annular bearing flange in the direction of the striking piston, wherein a connecting surface of each female coupling spline provided on the shank being at least in part formed by a curved concave surface extending substantially in an extension direction of the respective female coupling spline and having a radius of curvature which is less than a radial height of each of the male coupling splines provided on the shank.