PNEUMATIC PERCUSSION UNIT WITH COLLAR VALVE Russian patent published in 2003 - IPC

FIELD: construction equipment. SUBSTANCE: invention is related to driving holes in ground, to ramming bar elements into ground, to ground compaction. Pneumatic percussion unit has body with inlet and outlet holes, striker mounted in body for movement, chambers of forward and backward running, duct in striker communicating chambers of forward and backward running, limiters of forward and backward running made in internal surface of body, shut-off valve of chamber of backward running. Shut-off valve of chamber of backward running is collar valve in the form of elastic flange anchored with the use of ring in annular groove of striker with formation of slit clearance between elastic flange and annular groove for passage of used air. Annular groove of striker is connected with chamber of backward running. Sealing band tightly contacting internal surface of cylindrical body is made in face surface of elastic flange bordering on its side surface. EFFECT: enhanced serviceability of percussion unit and deepening of operational cycle by way of provision for reliable exhaust from chamber of backward running over entire travel of striker during power stroke. 3 dwg