PERCUSSIVE DRILLING GEAR Russian patent published in 1994 - IPC

FIELD: break-down of rocks and artificial materials. SUBSTANCE: body of hammer has annular bore with diameter equal to outer diameter of shank which is located at height of stepped valve in initial position. Throttle hole is made at height of overflow space through which overflow and drain spaces of hammer are permanently intercoupled. Diameter of striker on which stepped valve is put is bigger from side of arming space than its diameter on side of collecting space of hammer. EFFECT: increased operational efficiency. 5 dwg