Patent attributes
A hydraulic mold clamping unit, in particular for an injection molding machines or a press, includes a fixed lower platen and an upper plated which is moved by an open-close mechanism in a vertical direction. The open-close mechanism includes at least one hydraulic cylinder of a first type having a double-acting piston, and at least one hydraulic cylinder of a second type. A hydraulic pump system is operatively connected to both sides of the hydraulic cylinder of first type, and a pressure accumulator is operatively connected to the hydraulic cylinder of second type. In order to realize an energy-efficient operation of the upper platen at little pressure build-up, a proportional or regulation valve is disposed in the pump system for modifying a back pressure in the hydraulic cylinder of first type, when closing the lower and upper platens.
