PERCUSSIVE DEVICE Russian patent published in 1995 - IPC

FIELD: mining and metallurgical industries. SUBSTANCE: percussive device is a hydraulic hammer whose control step valve is installed in body coaxially to striker and serves as single control member of hammer. Control step valve has piston protrusion in its middle part. Protrusion has throttling hole for flow of working fluid from chamber above piston protrusion to chamber under piston protrusion. Step valve is a ring type with multistage bore opened to cocking hollow. Diameter of stage above piston protrusion is less than that under piston protrusion. Inner circular bore in valve shoulder on the side of cocking hollow, at the moment of beginning of opening of body discharge holes by valve is conjugated with body seat. EFFECT: higher efficiency. 6 dwg