PERCUSSION DRILLING MACHINE-DRILL SHANK COUPLING

摘要

A coupling arrangement for a percussion drilling machine for coupling of a shank (7) unrotatably to a frame bushing (2) rotatably mounted in a frame and rotated by a rotating device. The frame bushing is provided with axial driving grooves (12) opening towards the shank and the shank is provided with axial counter grooves (13) opening towards the frame bushing. Rod-like wedge pieces (11) are mounted each in a pair of grooves formed by the grooves. The cross-section of each wedge piece comprises an arched surface portion (11a) and at least one planar surface portion (11b). Such wedge piece can adjust its position by turning in one groove of the pair of grooves so that the planar surface of the wedge piece is pressed into a planar contact with the planar surface of the other groove.