An electro-hydrostatic drive for realizing a rapid movement during a rapid movement phase, a force-building movement during a force-building movement phase. The apparatus comprises a hydro-machine with variable volume and/or rotational speed, driven by an electric motor, for providing a volume-stream of a hydraulic fluid, a first cylinder with a piston chamber, an rod chamber, and a plunger rod, a reservoir, a pressure source, a relief valve, a check valve, a fluid connection between the piston chamber and the hydro-machine, a fluid connection between the rod chamber and the hydro-machine, a fluid connection between the piston chamber and the reservoir, a fluid connection between the rod-chamber-side port of the hydro-machine and the reservoir, a fluid connection, through the relief valve, between the reservoir and the pressure source. The relief valve is for pressure safety of the reservoir, and the check valve has a fluid connection from the pressure source to the rod-chamber-side port of the hydro-machine, during the rapid movement phase, a first part of the hydraulic fluid is piped through the fluid connection between the piston chamber and the hydro-machine and the fluid connection between the rod chamber and the hydro-machine, and a second part of the hydraulic fluid communicates through the fluid connection between the piston chamber and the reservoir, during the force-building movement phase, a first part of the hydraulic fluid is piped through the fluid connection between the piston chamber and the hydro-machine and the fluid connection between the rod chamber and the hydro-machine, and a second part of the hydraulic fluid is piped through the fluid connection between the rod-chamber-side port of the hydro-machine and the reservoir.

An automatic residual load relief system for hydraulic compactors having rotary pumps relieves residual load inherent in the compacted material by releasing hydraulic fluid from the cylinder prior to reversal of the rotary pump while preventing the fluid from returning to the pump. The system comprises in general a rotary pump powered by a motor, one-way suction check valves, a flow check valve, a one-way, normally-open, pilot operated check valve, a cylinder comprising a reciprocating piston, the piston defining a disk void and an annular void within the cylinder, and a tank.

A pressure measuring system, including a tube system having at least one first device for measuring pressure in a fluid. The at least one first device includes a coupling element, at least one pressure transducer and at least one measuring chamber, which can be filled with a fluid. Between the first device and the feed of the fluid, the tube system has a second device for regulating a fluid flow, the second device having a tube section through which fluid can flow and at least one tube clamp, which can be set in the regulation positions open, closed and perfused.

The invention relates to a method for making conveyor belts in an apparatus having a vulcanizing press. The method minimizes the press opening times and the throughput of the press is thus optimized. With the method, a check is made during the method whether a conveyor belt blank is present for vulcanizing in the press, and depending on the information from this check, the decision is made as to how far the press opens the press plates. Here, an operating open position and a full opening of the press are provided.

A hydraulic press includes a workbench having four corners provided with uprights. The uprights are arranged in two rows front and rear, and the tops of the uprights in each row are connected by an upper beam extending in a left-right direction. Tie rods are inserted in the front and rear of each upright. The tie rods each have an upper end protruding from the top of the upper beam and fixed to the upper beam by an upper nut and a lower end protruding from the bottom of the workbench and fixed to the workbench by a lower nut. A central cylinder is provided at the center of the upper beam. Side cylinders are symmetrically arranged on the left and right of the central cylinder. The lower ends of plungers of the central cylinder and the side cylinders are fixedly connected to a top of a slider.

An automatic residual load relief system for hydraulic compactors having rotary pumps relieves residual load inherent in the compacted material by releasing hydraulic fluid from the cylinder prior to reversal of the rotary pump while preventing the fluid from returning to the pump. The system comprises in general a rotary pump powered by a motor, one-way suction check valves, a flow check valve, a one-way, normally-open, pilot operated check valve, a cylinder comprising a reciprocating piston, the piston defining a disk void and an annular void within the cylinder, and a tank.