Hydraulic percussion machine

An improved hydraulic percussion machine, comprising:

• a body;
• a piston within said body;
• hydraulic passages including a high pressure line and a valve associated with said body to define an hydraulic operating circuit;
• an hydraulic pressure accumulator disposed in axial alignment with and above said piston;
• said accumulator having a separate gas-filled chamber and a liquid-filled chamber, said accumulator being in communication with said piston for storing piston stroke energy which accelerates said piston for striking against a tool disposed at the working end of said machine;
• wherein the improvement comprises:
• providing said machine with a separate stroke standardizing circuit for maintaining accumulator pressure independent of pressure within said hydraulic operating circuit;
• said standardizing circuit being provided by pressure monitoring means disposed within hydraulic passages connecting said operational circuit and said accumulator;
• said monitoring means serving to monitor pressure in said accumulator responsive to piston stroke;
• and said standardizing circuit being self-regulating during machine operation to permit said piston stroke to be independent of liquid pressure and volumetric flow in said high pressure line supplying said operating circuit.