A hydraulic system for a cyclically operating shaping machine includes at least one hydraulic drive unit for cyclically driving a component of the shaping machine at a start time; at least one pump; and at least one hydraulic accumulator which can be discharged for driving the at least one hydraulic drive unit and which can be charged up by operation of the at least one pump. An open-loop or closed-loop control unit is also provided for control of the at least one pump. The open-loop or closed-loop control unit is adapted to operate the at least one pump continuously until the start time of the at least one hydraulic drive unit to charge up the at least one hydraulic accumulator until the start time of the hydraulic drive unit.

A hydraulic system for a cyclically operating shaping machine includes at least one hydraulic drive unit for cyclically driving a component of the shaping machine at a start time; at least one pump; and at least one hydraulic accumulator which can be discharged for driving the at least one hydraulic drive unit and which can be charged up by operation of the at least one pump. An open-loop or closed-loop control unit is also provided for control of the at least one pump. The open-loop or closed-loop control unit is adapted to operate the at least one pump continuously until the start time of the at least one hydraulic drive unit to charge up the at least one hydraulic accumulator until the start time of the hydraulic drive unit.

Disclosed is a hydraulic system for a molding system, the molding system having a clamp actuator and an injection actuator, the hydraulic system comprising a clamp accumulator for storing hydraulic fluid for use in actuating the clamp actuator; an injection accumulator for storing hydraulic fluid for use in actuating the injection actuator; a pump for conveying hydraulic fluid to the clamp accumulator and the injection accumulator; and a selector valve for selectively fluidly connecting the pump to one of the clamp accumulator and the injection accumulator.

A closing unit for a shaping machine includes mutually moveable mold mounting plates suitable for carrying mold tool portions, a first hydraulic cylinder adapted to apply a closing force to the mold mounting plates, a second hydraulic cylinder, and a pressure storage device connected to the first hydraulic cylinder and adapted to store a pressure prevailing in the first hydraulic cylinder upon pressure relief at a storage device pressure. A hydraulic interconnection of the pressure storage device with the second hydraulic cylinder allows the storage pressure stored in the pressure storage device to be used for locking and/or unlocking the locking device.

A method is described for operating an actuator adapted to move via a pressurized fluid circuit a valve pin of an injection nozzle for molten material within a mold, wherein the valve pin moves from a closing position, where no molten material passes through the nozzle, to an opening position, where molten material passes through the nozzle, and the actuator comprises a chamber and a piston that is movably mounted in the chamber, linearly displaced by the thrust of the fluid and connected to the valve pin to move it.

The valve pin is moved by injecting or extracting a predetermined amount of fluid into/from the chamber.

A closing unit for a shaping machine includes mutually moveable mold mounting plates suitable for carrying mold tool portions, a first hydraulic cylinder adapted to apply a closing force to the mold mounting plates, a second hydraulic cylinder, and a pressure storage means connected to the first hydraulic cylinder and adapted to store a pressure prevailing in the at least one first hydraulic cylinder upon pressure relief as a storage means pressure. A hydraulic interconnection of the pressure storage means with the second hydraulic cylinder allows the storage pressure stored in the pressure storage means to be used for locking and/or unlocking the locking device.

In one aspect, there is provided an injection molding system configured to operate in a plurality of cycles. The system comprises, amongst other things, a controller that is configured for performing a comparison of a variable pressure setpoint with a target pressure value. The controller is configured to, when the target pressure value is less than the variable pressure setpoint by at least a predetermined lower bound, (i) decrease the variable pressure setpoint to a reduced variable pressure setpoint and (ii) not further decrease the variable pressure setpoint from the reduced variable pressure setpoint until the pump assembly operates for a plurality of stabilizing cycles at the reduced variable pressure setpoint.

In one aspect, there is provided an injection molding system configured to operate in a plurality of cycles. The system comprises, amongst other things, a controller that is configured for performing a comparison of a variable pressure setpoint with a target pressure value. The controller is configured to, when the target pressure value is less than the variable pressure setpoint by at least a predetermined lower bound, (i) decrease the variable pressure setpoint to a reduced variable pressure setpoint and (ii) not further decrease the variable pressure setpoint from the reduced variable pressure setpoint until the pump assembly operates for a plurality of stabilizing cycles at the reduced variable pressure setpoint.

A toggle lever clamping unit for an injection molding machine includes fixed and movable platens, a support plate, a toggle lever mechanism operatively connected with both the support plate and the movable platen, a cross clamp operatively connected with the toggle lever mechanism and movable along a machine longitudinal axis, and an electric drive for moving the cross clamp. In addition, a hydraulic drive is operatively connected with the cross clamp and includes a fluid-operated piston cylinder system, with the lengths of the cylinder and the piston rod being coordinated with one another such that the hydraulic drive follows a travel path of the cross clamp as the movable platen travels between an open position of the clamping unit, in which the toggle lever mechanism is swung in, and a closed position in which the toggle lever mechanism assumes a predeterminable extended position and a clamping force is built up.

A memory assembly (800), comprising: a storage media (802) tangibly embodying executable commands configured to direct a molding-system controller (114) to send a command signal to the first accumulator-control valve (106) and the first actuator control valve (110), the command signal configured to request: (i) the first accumulator-control valve (106) to permit flow of hydraulic fluid from the first accumulator assembly (108) to the first actuator assembly (112), and (ii) the first actuator control valve (110) to permit flow of hydraulic fluid from the first pump assembly (104) to the first actuator assembly (112) for the case where the molding-system controller (114) determines that the first actuator assembly (112) requires the flow from both the first pump assembly (104) and the first accumulator assembly (108) during a portion of a molding cycle.