Abstract: An electrohydraulic drive unit of a machine tool having a tool that can be moved up and down is provided and comprises a double-acting hydraulic cylinder-piston arrangement oriented in upright manner and having a piston projecting downwardly from the cylinder and being coupled with the tool, a valve block flanged to the cylinder at the upper end region thereof and having a servo suction valve, a hydraulic-fluid reservoir flanged to the valve block at a first hydraulic interface and a motor-pump unit having an electric motor and a hydraulic pump driven thereby and flanged to the valve block at a second hydraulic interface. A suction line, extends from the first hydraulic interface to the second hydraulic interface through the valve block.

Abstract: A land vehicle is provided having a chassis and having a plurality of corner support units. Each of the corner support units has a support leg which is mounted in a swiveling manner in a bearing shoe, which is rigidly attached to the land vehicle, about a substantially horizontal axis. The length of the support leg is telescopically variable. The support leg comprises at least two pipe sections, which can be displaced relative to each other in the longitudinal direction. A hydraulic cylinder is arranged in the interior of the support leg by means of which the position of the at least two pipe sections relative to each other, and consequently the length of the support leg, can be modified. A separate hydraulic assembly, arranged on the bearing shoe of each affected corner support unit and loading the hydraulic cylinder, is allocated to each corner support unit.

Abstract: A land vehicle is provided comprising a chassis and a plurality of corner post units mounted on the chassis, each corner post unit includes a support member that is mounted on the chassis, an intrinsically rigid support arm that is hinged to the support member so as to be able to pivot about a substantially horizontal axis, and a pivoting drive for the support arm. According to the invention, each of the corner post units comprises at least one hydraulic cylinder-piston unit, one end of which is hinged to the support member and the other end of which is hinged to the support arm, and a hydraulic unit that acts directly on the cylinder-piston unit and is arranged on the support member.

Abstract: The invention relates to a controlled three-way proportional valve unit comprising: a valve assembly with two individual valves; an actuating device actuating valves of the valve assembly; and a control unit acting upon the actuating device and having a control signal input, the valves of the valve assembly being designed as poppet valves arranged on opposite sides and having counter-rotatable valve spindles. The valve spindles are prestressed relative each other in opposite directions by a prestressing element such that, when the actuating unit is inactive, a first poppet valve is open and the second poppet valve is closed. The actuating device comprises an actuator common to both poppet valves, acts upon the two valve spindles and changes the position of the valve spindles counter to the effect of the prestressing element.

Abstract: A machine press is provided in which at least one hermetically sealed hydraulic drive unit is switchable from a working mode, in which a base pressure above ambient pressure is continually exceeded, into a rest mode. To this end, in parallel with a pressure converter, to the high-pressure side of which a pressure store and a raising working chamber of a cylinder piston unit are connected, a bypass is provided, having a first blocking valve that is controllable by a control unit and, in its blocking position, blocks the through-flow direction from the high-pressure side of the pressure converter to the low-pressure side. Furthermore, the low-pressure side is connectable to a lowering working chamber via a second blocking valve controllable by the control unit. The pressure output of the hydraulic unit is connectable to the raising working chamber via a third blocking valve controllable by the control unit.

Abstract: A drive unit is provided, particularly a drive unit for operating flow-control valves, comprising a housing, an electrical input, an electromechanical converter assembly, a mechanical output, and an electronic controller. The controller comprises an input unit having at least one pushbutton, which penetrates the housing and can be depressed against the action of a restoring device, and comprises a contactless switch that is actuated by the at least one pushbutton. A mechanical stop independent of the switch itself is associated with the position of the pushbutton that actuates the switch.

Abstract: The invention relates to a fluidic actuator comprising a drive element (2) that can be supplied with a pressure fluid and a two-stage proportional position controller (3) controlling the supply with pressure fluid to the drive element, said actuator comprising an electro-fluidic pilot stage (10) of the position controller, exactly one electromechanical transducer (14) and exactly one proportional valve (16) actuated by said transducer and having a pressure fluid inlet (18), a control pressure outlet (19) and a discharge outlet (20). A fluidic power stage (11) of the position controller comprises two poppet valves (24, 25) having associated pressure-to-distance converters that are supplied by a common control chamber (34) which is connected to the control pressure outlet (19) of the pre-stage (10).

Abstract: The hydraulic drive system of a machine press comprises at least two independent hydraulic drive units. In each of said hydraulic drive units at least one hydraulic cylinder, which is connected via valves and a main pressure line under supply pressure to a pump driven by a motor, raises and lowers the upper tool carrier. The rotational speed of the motor is adjustable via the numeric machine control, in which a rotational speed profile defined across the work cycle is stored. Furthermore, a pressure-limiting unit limiting the level of the supply pressure is provided, which at least during a part of the work cycle limits the supply pressure to the lower pressure of a pressure profile defined across the work cycle and stored in the numeric machine control and the actual load pressure increased by an extra amount at the at least one hydraulic cylinder.

Abstract: A fluid-operated actuating drive on a valve comprising a base unit (2) having an electro-fluidic signal converter and a fluidic controller and at least one linear actuator (4) that can be actuated using the fluidic controller, wherein the gate (11) of the linear actuator is directly or indirectly coupled to the inlet of the valve. A control unit (22) is connected to a signal input of the base unit, wherein the signal output is connected to the electro-fluidic signal converter. The actual value signal of a measurement transducer (24) associated to the valve is fed back to the control unit. A fluidic internal control circuit (27) is arranged functionally between the signal input and the at least one linear actuator, preferably downstream of the electro-fluidic signal converter.

Abstract: A fluid-operated actuating drive (1) on a valve, in particular a shut-off, safety or regulating valve, comprising a base unit (2) having control valves, two linear actuators (6, 7) which are located opposite of each other and can be actuated fluidically, and a mechanical converter (5) which is arranged between the two linear actuators and couples the gates thereof to each other, wherein the outlet of the converter is coupled to the inlet of the valve. To this end, the actuating drive is composed in a modular manner of individual components joined to form a functional unit in the form of the base unit, the two linear actuators and the mechanical converter.

Abstract: A fluid-operated actuating drive (1) on a valve, in particular a shut-off, safety or regulating valve, comprising a base unit (2) having control valves, two linear actuators (6, 7) which are located opposite of each other and can be actuated fluidically, and a mechanical converter (5) which is arranged between the two linear actuators and couples the gates thereof to each other, wherein the outlet of the converter is coupled to the inlet of the valve. To this end, the actuating drive is composed in a modular manner of individual components joined to form a functional unit in the form of the base unit, the two linear actuators and the mechanical converter.

Abstract: A fluid-operated actuating drive on a valve comprising a base unit (2) having an electro-fluidic signal converter and a fluidic controller and at least one linear actuator (4) that can be actuated using the fluidic controller, wherein the gate (11) of the linear actuator is directly or indirectly coupled to the inlet of the valve. A control unit (22) is connected to a signal input of the base unit, wherein the signal output is connected to the electro-fluidic signal converter. The actual value signal of a measurement transducer (24) associated to the valve is fed back to the control unit. A fluidic internal control circuit (27) is arranged functionally between the signal input and the at least one linear actuator, preferably downstream of the electro-fluidic signal converter.

Abstract: In a machine press having a lower and an upper tool carrier, a hydraulic drive acting on the upper tool carrier comprises at least one closed hydraulic drive system that can be switched between rapid motion and press motion, the drive system having at least one hydraulic cylinder piston unit. The hydraulic liquid of the at least one hydraulic drive system is stored in a pressure accumulator fanning the storage container, supplying the entire associated hydraulic drive system permanently with at least a base pressure above the ambient pressure. There is no hydraulic connection whatsoever between the working chamber on the piston rod side and the working chamber on the piston side of at least one hydraulic cylinder piston unit. The upper tool carrier is pre-stressed into the upper final position thereof by means of a spring unit.

Abstract: In a water craft having at least one hull and at least one drive motor, which has an operative drive connection via a drive train to a drive head comprising a propulsion means, the drive head is laterally pivotably mounted relative to the hull with respect to a steering axis. For the lateral adjustment of the drive head relative to the hull, at least one hydraulic steering cylinder is provided, which can be acted on by a hydraulic steering system comprising a hydraulic pump. A hydraulic system, which comprises a separate hydraulic unit and is intended to be used to act on a hydraulic load not serving to steer the water craft, can be coupled to the hydraulic steering system in order to effect an emergency steering function in the sense of acting on the hydraulic steering cylinder.

Abstract: A piezoelectric valve having a housing is provided with an inner chamber, in which ends at least one nozzle communicating with an associated port for a medium and provided with a sealing seat having a seat face, a deformable piezoelectric bending element being received in the inner chamber of the housing in such a way that the nozzle can be closed by a portion of the bending element movable relative to the nozzle in response to deformation of the bending element, and the bending element being provided with padding of an elastically resilient material, at least in its region opposite the nozzle. This sealing seat is disposed at the end face of a nozzle insert, which is disposed to be displaceable substantially perpendicular to the seat face in a receptacle fixed to the housing, a thermally expandable compensating member acting between the receptacle and the associated nozzle insert.

Abstract: An electrohydraulic booster comprises an electromechanical transducer and a hydromechanical power stage which is connected to a pressurized medium supply and encompasses a cylinder and a piston that can be moved therein along the working axis. The electromechanical transducer acts on a spool valve which is associated with the hydromechanical power stage, is disposed at least in part inside the piston, is guided within a guiding bore in such a way as to be movable along the working axis, and has two first leading edges that cooperate with corresponding second leading edges located on the guiding bore in order to form a hydraulic sequential control. The guiding bore consists of two parts, i.e. a cylinder-mounted first section and a second section which can be moved along the working axis and comprises the second leading edges.

Abstract: An electrohydraulic booster comprises an electromechanical transducer and a hydromechanical power stage which is connected to a pressurized medium supply and encompasses a cylinder and a piston that can be moved therein along the working axis. The electromechanical transducer acts on a spool valve which is associated with the hydromechanical power stage, is disposed at least in part inside the piston, is guided within a guiding bore in such a way as to be movable along the working axis, and has two first leading edges that cooperate with corresponding second leading edges located on the guiding bore in order to form a hydraulic sequential control. The guiding bore consists of two parts, i.e. a cylinder-mounted first section and a second section which can be moved along the working axis and comprises the second leading edges.

Abstract: A hydraulic circuit for actuation of a hydraulic working cylinder (1) having a one-sided piston rod (1a), comprising a reversible pump (4) whereby both sides of said pump are connected via a supply line (5) and a first two-way valve (6) to the tank (7) containing hydraulic medium and through releasable control check valves (8) to the working cylinder (1). Both sides of the arrangement are further connected respectively to a hydraulic closeable valve (21, 31) through a discharge line (20, 30) and also to the tank (7) through a replenishing suction line (22, 32) having a corresponding suction valve (9). Each of said hydraulic closeable valves (21, 31) is controlled by the pump (4) through a second two-way valve (4).

Abstract: A telescopic lifting assembly designed particularly for the hydraulic height adjustment of a medical treatment table includes two antiparallel juxtaposed linear drives (2, 3) connected functionally one behind the other in the direction of actuation (1) whereby the inner components (6) are connected to a coupling piece (7) which is provided with guide surfaces (14) cooperating with the outer components (5) in the direction of actuation (1). A secure and stable guiding mechanism is made possible thereby along the entire lifting range.

Abstract: A piezoelectric valve having a housing is provided with an inner chamber, in which ends at least one nozzle communicating with an associated port for a medium and provided with a sealing seat having a seat face, a deformable piezoelectric bending element being received in the inner chamber of the housing in such a way that the nozzle can be closed by a portion of the bending element movable relative to the nozzle in response to deformation of the bending element, and the bending element being provided with padding of an elastically resilient material, at least in its region opposite the nozzle. This sealing seat is disposed at the end face of a nozzle insert, which is disposed to be displaceable substantially perpendicular to the seat face in a receptacle fixed to the housing, a thermally expandable compensating member acting between the receptacle and the associated nozzle insert.