A hydraulic device improved closure, particularly for machines injection molding.

摘要

The invention relates to a hydraulic closing device for injection moulding machines or other moulding machines, the device comprising a closing piston 5, which is hydraulically slidable in a cylinder 1 and is connected by guide members 6 to a clamping plate 7 on which a mould half 8' is mounted. Cylinder chambers 23', 23'' on both sides of the closing piston 5 communicate through each of ducts 22', 22'' provided with a respective non-return restrictor valve 24', 24'' with a changeover valve 20 which is also connected to a pressure pump P and a tank T. Both cylinder chambers 23', 23'' can be pressure-biased or pressure- relieved alternately by means of the directional valve 20 in order to move the piston 5 (and thus the plate 7 and mould half 8') towards or away from the other mould half 8. Apertures 9 in piston 5 are closed by respective valve seats 12 towards the end of the mould-closing movement of piston 5 to permit the pressure from pump P to exact a large force on piston 5 through chamber 23' thereby thrusting the mould halves 8, 8' against each other with a large force. IMAGE