A pressure intensifier for fluids, in particular for liquids, comprising a cylinder block in which a pressure intensifier piston and a control piston move cyclically, wherein the pressure intensifier piston forms a high-pressure working chamber and a low-pressure working chamber in the cylinder block and the cylinder block has a low-pressure connection for feeding in low-pressure fluid from outside, a high-pressure connection for discharging higher-pressure working fluid towards the outside and a connection for discharging fluid whose working capacity in the pressure intensifier is exhausted, wherein the cylinder block has a coupling portion rigidly connected with it, which can be inserted into a receiving bore of a hydraulic block and fixed there, so that the receiving bore encloses the coupling portion, wherein the coupling portion has at least two fluid transfer regions fluidically separated by a seal, for exchanging fluid between the pressure intensifier and the hydraulic block into which it is inserted.

In a hydraulic shield support system, a plurality of pressure intensifiers are respectively provided for a plurality of hydraulic props. Each pressure intensifier is operated to increase a system pressure to an increased pressure for supplying fluid at the increased pressure to a pressure chamber of the associated hydraulic prop. The plurality of pressure sensors measure the pressures of the fluid supplied to the respective hydraulic props. A control unit sets a plurality of desired pressures for the plurality of hydraulic props, and stops operation of the respective pressure intensifiers when the set desired pressure has been reached.

In a hydraulic shield support system, a plurality of pressure intensifiers are respectively provided for a plurality of hydraulic props. Each pressure intensifier is operated to increase a system pressure to an increased pressure for supplying fluid at the increased pressure to a pressure chamber of the associated hydraulic prop. The plurality of pressure sensors measure the pressures of the fluid supplied to the respective hydraulic props. A control unit sets a plurality of desired pressures for the plurality of hydraulic props, and stops operation of the respective pressure intensifiers when the set desired pressure has been reached.

A power transfer unit includes a first hydraulic circuit, a second hydraulic circuit fluidly connected to the first hydraulic circuit, a pump and motor assembly fluidly connected between the first hydraulic circuit and the second hydraulic circuit, an isolation valve arranged along the first hydraulic circuit and fluidly connected to an inlet of the pump and motor assembly. The isolation valve is movable between a closed position and an open position to prevent and enable high-pressure fluid flow to the inlet, respectively. An unloader valve is arranged along the second hydraulic circuit and fluidly connected to an outlet of the pump and motor assembly, and an orifice is arranged along the second hydraulic circuit and fluidly connected to the unloader valve to reduce back pressure in the second hydraulic circuit.

A power transfer unit includes a first hydraulic circuit, a second hydraulic circuit fluidly connected to the first hydraulic circuit, a pump and motor assembly fluidly connected between the first hydraulic circuit and the second hydraulic circuit, an isolation valve arranged along the first hydraulic circuit and fluidly connected to an inlet of the pump and motor assembly. The isolation valve is movable between a closed position and an open position to prevent and enable high-pressure fluid flow to the inlet, respectively. An unloader valve is arranged along the second hydraulic circuit and fluidly connected to an outlet of the pump and motor assembly, and an orifice is arranged along the second hydraulic circuit and fluidly connected to the unloader valve to reduce back pressure in the second hydraulic circuit.

The improved hydraulic system utilizes a secondary hydraulic force control circuit that changes the gripping force on the load independently of movement of the clamp arms.

The improved hydraulic system utilizes a secondary hydraulic force control circuit that changes the gripping force on the load independently of movement of the clamp arms.

The invention relates to a system that intensifies hydraulic pressure, which comprises a main actuation subsystem and a direction-change sub-system. The main actuation subsystem comprises: a motor; a pump; a first piston with a plunger that moves linearly; a travel-limit sensor and a two-way valve at each end of the piston; a pressure control valve connected to the two-way valves; a second piston similar in always to the first and connected to the pressure control valve; a hydraulic motor connected to the two-way valves of the second piston to generate work; and a fluid-cooling means. The direction-change subsystem comprises a secondary motor, a second pump, a pressure accumulator and a pair of solenoid valves for the parallel and independent operation of the two-way valves of the main actuation subsystem.

An actuator pressure intensifying assembly includes a mode valve and a gear motor assembly, the mode valve arranged to receive, at an input port, a supply pressure and to provide, at an output port, a control pressure to an actuator, the mode valve further configured to move, in response to the supply pressure exceeding a predetermined activation threshold, from a first mode in which the supply pressure flows directly from the input port to the output port in a first fluid flow path, and a second mode in which the supply pressure flows from the input port to the output port in a second fluid flow path which includes the gear motor assembly between the input port and the output port which intensifies the supply pressure such that the control pressure is higher than the supply pressure.

An actuator pressure intensifying assembly includes a mode valve and a gear motor assembly, the mode valve arranged to receive, at an input port, a supply pressure and to provide, at an output port, a control pressure to an actuator, the mode valve further configured to move, in response to the supply pressure exceeding a predetermined activation threshold, from a first mode in which the supply pressure flows directly from the input port to the output port in a first fluid flow path, and a second mode in which the supply pressure flows from the input port to the output port in a second fluid flow path which includes the gear motor assembly between the input port and the output port which intensifies the supply pressure such that the control pressure is higher than the supply pressure.