DRILL BIT Russian patent published in 1997 - IPC

FIELD: mining machinery. SUBSTANCE: this relates to tooling of subsurface pneumatic strikers. Peripheral part of drill bit is made in the form of removable peripheral ring having open passages in its body passing through seat bottom of rock-crushing inserts and intended for pressing-out of these inserts. Inserts are enclosed in more softer bushes which protect surface of seats at pressing inserts in and out. Internal row of inserts of removable peripheral ring is extended above inserts of bottom-hole end of tail-piece and this ensures configuration of bottom-hole with high central protrusion, and crushing it by inserts requires less energy and will not lead to their significant wear. Cleaning of sludge is effected by cleaning agent delivered via passages. Discharge of sludge into annular space is effected through sludge outlet slots made in removable peripheral ring. EFFECT: high efficiency. 1 cl, 1 dwg