Drill bit for hammer drill - has passageway for cooling medium formed by grooves in drill bit shank and outer tube

摘要

The drill bit (1) for a hammer drill has longitudinal grooves in its outer surface and a tube fits over the shank of the drill bit so that passageways (10) are formed for a cooling medium which also removes the fragments of material. The passageways run into an annular chamber (12) formed by circumferential groove (12) in the drill bit. This annular chamber is connected by a passageway (15) to a recess (13) in the end face of the drill bit. The recess is connected to a central axial hole through a short oblique hole (22) so that the cooling medium flows back through the axial hole. ADVANTAGE - The oblique hole improves the efficiency of the circulation of the cooling medium.