Shothole drifter chisel shank lock - has bush lugs driven into groove in drill tube for twisting and locking by spring insert

The chisel shank lock for percussive drifters used in shot and blasthole drilling in the mining industry consists of a bush fitted onto the drill tube. For a secure hold, the rear endwall of the bush (8) has radial lugs (11) which fit into open ended and dead-end longitudinal grooves with associated cross linking grooves machined in the drill tube (4). The lugs are forced along the grooves into the cross grooves (12) when pressure is applied to the bush from inside (8, 9). When the bush is twisted round ints axis, the lugs move over into the dead-end grooves and engage these under power of a spring loaded member inserted between the bush and tube (4) which thus locates the bush in the operating position.