Drilling head of a rotary impact drill

摘要

An exhaust channel in a rock drilling head of a rotary impact drill has an opening which extends over the front face of the drill shaft and over the adjoining peripheral surface of the drill shaft. Clogging of the exhaust channel is prevented by providing clearances between the forward and peripheral surfaces of the drilling head and the bored hole which are too small to permit the passage of rock particles large enough to block the exhaust channel.