Device for controlling the speed of advance of a piston in a hydraulic cylinder, particularly for controlling the rate of injection and the pressure of the multiplier in a pressure die-casting machine

摘要

The device comprises an accumulator 1 in which a piston 2 slides to divide it into a first half-chamber 3 filled with pressurized gas and a second half-chamber 4 filled with a fluid that can be supplied to a hydraulic cylinder 6. Between the accumulator 1 and the cylinder 6 are a plurality of solenoid valves 12, 13, 14 that can be energized alternately or so as to overlap with each other to give different levels of the speed at which the piston 7 slides along the hydraulic cylinder 6.