Abstract: The invention relates to a hydraulic energy recovery system (101) having an output drive unit (103), which can be actuated by a drive unit (102), and by which a hydraulic motor-pump unit (104) can be driven which, in at least one energy feed position, supplies an energy storage device (106) and/or working hydraulics (107) with fluid; and which, in a recuperation position, discharges fluid under pressure from the energy storage device (106) at least to the working hydraulics (107) and/or is used to actuate the output drive unit (103).

Abstract: A method and an arrangement in a forest work unit, comprising storing power produced by a primary power source in an energy storing means in at least one first phase of a working cycle of the forest work unit by controlling a hydraulic pump-motor to convert at least some of the power produced by the primary power source into hydraulic power and by supplying it to the energy storing means to be stored therein. At least one second phase of the working cycle of the forest work unit comprises supplying stored power from the energy storing means for driving at least one tool.

Abstract: A control device for an adjustable hydraulic pump (1), wherein the hydraulic pump is connected to a plurality of users, by delivery lines (5a-d). A first control line (18a-d), is connected to each of the delivery lines downstream of a respective proportioning throttle (6a-d). A first pressure change device (17) selects a highest pressure prevailing in the first control lines and supplies it to a delivery flow control valve (15), which controls an adjusting pressure for an adjusting device (7) for the hydraulic pump, based on a pressure difference between the highest pressure from the first pressure change device and a pressure from a second control line (19) connected to the output of the pump.

Abstract: The invention relates to a device for the output regulation of at least one variable displacement pump (1), delivering into a working line, driven by a motor, through adjustment of its displacement by means of a setting device (7) biased in the direction of maximum displacement and which can be acted upon with a setting pressure (20), having a regulation valve (18) associated with the setting device (7), which regulation valve can be acted upon by a counter-pressure corresponding to the working pressure in the working line, whereby the regulation valve (18) responds when the control pressure is greater than the counter-pressure, and so regulates the setting pressure action on the setting device (7) in the direction of a reduction of the displacement of the variable displacement pump (1) that the product of working pressure and output is constant.

Abstract: A power or moment regulation device for an adjustable hydraulic pump having a servo setting apparatus providing for a smooth stepless setting of the pump delivery quantity. In the device, the delivery quantity setting is determined in dependence upon the delivery pressure of the hydraulic pump in a delivery pressure line and a control pressure in a control line. The setting apparatus has a spring setting a pump setting member in the direction of maximum delivery quantity and a piston acting upon the pump setting member in the opposite direction of delivery quantity reduction. The piston is acted upon via a hydraulically actuated control valve with the delivery pressure. The actuation of the control valve is effected by the control pressure in the control line. A moment valve is provided, the closure force of which is determined by a metering spring arrangement connected with the pump setting member and biased in dependence upon the delivery quantity setting.

Abstract: A total power regulation device for a plurality of variable displacement pumps (1, 2), each having a regulation valve (18) which regulates its displacement volume, which is acted upon--against a counter-pressure--by a control pressure corresponding to the working pressure of the variable displacement pump. When the control pressure exceeds the counter-pressure, the regulation valve regulates the variable displacement pump along a characteristic line (KL) of constant torque. To adjust the desired values of the individual drive torques simply, and to prevent torques from exceeding a desired value, an electronic control unit (16)--connected to measuring detectors (25) for detecting the displacement volumes of the variable displacement pumps--stores the desired value totals of the counter-pressures and the torque characteristic lines (KL) of the variable displacement pumps, and has a desired value setting device (27) for dividing the desired value total.