JPS57197321A - Composite mammer - Google Patents

Abstract

PURPOSE:To increase the striking force of a composite hammer by using a system in which a piston rod is connected coaxially with pistones fitted into a liquid-pressure cylinder and an air-pressure cylinder, and a weight is connected to the piston rod and operated by the weight. CONSTITUTION:Under a condition that a short-circuit valve 44 is switched to the position (a), a high-pressur liquid from a pump 41 flows to the lower chamber 23 of a liquid-pressure cylinder to raise a piston 25 and then to lift up a weight 37. On the other hand, as a piston rod 36 rises, a gas in the upper chamber 31 of an air-pressure cylinder 29 is compressed by a piston 32 and stored in a pressure storage 45. When the weight 37 rises up to a set position and the short-circuit valve 44 is switched to the position (b), the liquid in the lower chamber 23 of the liquid-pressure cylinder 22 is moved to the upper chamber, and when the piston 32 begins to go down as the piston 25 goes down, the gas in the pressure storage 45 flows into the upper chamber 31 and expands, and thereby the piston 32 is strongly pressed down and the weight 37 drops abruptly.