Patent ID: 7493757

Claim:
A hydraulic pressure supply unit with two exits that are alternatively pressurized, with a reversible pumping unit comprising at least two pumps as well as a reversible electric motor that drives all pumps jointly and whereby one pump is a low-pressure pump and one pump is a high-pressure pump, and whereby the pressurized exits of both pumps are placed against the same exit of the pressure supply unit wherein both exits of high-pressure pump are separated from low-pressure pump by check valves, and whereby each pump is connected to the supply for hydraulic medium via its own shuttle valve, wherein both exits of low-pressure pump can be connected to a tank via pressure on-off valves, and whereby the control connection of pressure on-off valves is connected to the exits of high-pressure pump in such a way that the control connection of that pressure on-off valve on the currently pressurized side is applied with pressure by the currently pressurized exit of high-pressure pump.