Patent ID: 6877569

Claim:
A method for controlling the operating cycle of an impact device, the impact device being designed for breaking rock and comprising a frame, a percussion piston, working pressure surfaces formed on the percussion piston and acting both in the impact direction and in the return direction, working pressure ducts and discharge ducts for guiding pressure medium to act on the working pressure surfaces, and at least one control valve, the method comprising: varying the pressure medium flows acting on the working pressure surfaces of the percussion piston, by means of the control valves, so as to produce a reciprocating impact and return motion according to the operating cycle of the percussion piston, and for delivering impacts on a tool arranged in the impact direction of the percussion piston, and wherein the method further comprises the steps of measuring the position of the percussion piston by means of at least one sensor during an operating cycle and transmitting the measurement data to a control unit of the impact device; generating an electric control signal in the control unit, on the basis of the position of the percussion piston and on the control parameters supplied to the control unit for controlling an electrically driven control valve; and guiding the pressure medium, under the control of the electrically driven control valve, to act on the working pressure surfaces of the percussion piston, and away from them for controlling the operating cycle of the impact device.