Abstract: The invention concerns a water-hydraulic machine with at least two mutually movable parts, of which one has a surface of a plastic material with friction-reducing properties. In such a machine it is desired to enable the use of demineralised water. For this purpose, it is ensured that a layer of a carbon-containing material is arranged between the plastics material and the other part.

Abstract: The invention concerns a piston compressor, particularly a hermetically enclosed refrigerant compressor, with at least one cylinder a piston reciprocating in said cylinder, the piston being connected with a driving rod via a piston pin and having in its outer jacket surface a circumferential lubrication groove, the piston pin having a longitudinal bore, which is connected with a lubricant source. It is endeavoured to improve the lubrication. For this purpose, the longitudinal bore is open downward in the gravity direction and has a ventilation opening upward.

Abstract: A steering system and a method for steering a vehicle, that has a wheel steering and an articulated steering. The steering system (1) has a steering unit (2), a first steering motor arrangement (7), which acts upon steered wheels, a second steering motor arrangement (8), which acts upon a converting kit, and a selection valve (6), which connects the steering unit (2) with either the first steering motor arrangement (7) or the second steering motor arrangement (8) in such a way that a steering will activate either the wheel steering or the articulated steering.

Abstract: Inrush currents in the dc intermediate circuit of a motor controller necessitate the incorporation of protection circuits. These circuits usually take the form of a resistor inserted in series with the intermediate circuit, and the resistor is short-circuited after completion of inrush by a switch positioned in parallel with the resistor. To reduce cable-transmitted electrical noise an earthed noise-decoupling capacitor is added to the intermediate circuit, but it also requires protection against inrush currents. To minimise the number of components, a protection circuit is described which combines noise filtration and inrush protection.

Abstract: The invention relates to a device for damping the pitching of an engine-driven vehicle with a chassis and axles 5, at least one of which is mounted fixedly on the chassis. The aim of the invention is to provide a simplified corresponding device. To this end, the torque of at least one wheel borne on the axles (5) is influenced on the basis of the size of the pitching in such a way that the pitching. is damped.

Abstract: The invention relates to a method for compressing a compressible medium, in which at least two displacement elements, each having at least one limiting face extending helically in the cross section, are orbited in relation to each other under formation of at least one chamber, the volume of the chamber being changed by the orbiting movement, performing a cycle with a suction phase, a compression phase and a discharge phase, the chamber being opened and forming a suction chamber during the suction phase. It is endeavoured to improve the thermodynamic conditions during compression of a compressible medium. For this purpose, for the duration of the suction phase, the suction chamber is reduced by a volume limiting element in such a way that at the end of the suction phase the chamber has a volume of at least 90% of a maximum volume appearing during the suction phase.

Abstract: An electromagnetic flowmeter arrangement is disclosed, having a measuring tube (2), a coil arrangement (3, 4) for generating a magnetic field substantially perpendicular to the direction of flow through the measuring tube (2), an electrode arrangement (5, 6) substantially perpendicular to the direction of flow and to the magnetic field, an evaluating device and a testing device. In this connection, it is desirable to be able to carry out testing in a simple manner. For that purpose, the testing device comprises a elements (10-13) for applying voltage to the coil arrangement (3, 4) without generating a magnetic field, and an element for determining an ohmic and/or inductive and/or capacitive coupling between the coil arrangement (3, 4) and the coil evaluating device.

Abstract: A hydraulic valve system (1) has a supply connection arrangement having a high-pressure connection (P) and a low-pressure connection (T), a working connection arrangement, having two working connections (A, B) connectable with a motor (2), with a directional valve (4), which is arranged between the supply connection arrangement (P, T) and the working connection arrangement (A, B), and with a compensation valve (8), which is acted upon in a first operation direction by a spring (22) and a pressure in a pressure chamber (23), which is connected with a load-sensing line (LS), and in a second operation direction, which is opposite to the first operation direction, by a pressure at the directional valve (4).

Abstract: A hydraulic valve system (1) with a supply connection arrangement, has a high-pressure connection (P) and a low-pressure connection (T), and a working connection arrangement, having two working connections (A, B), which can be connected with a motor, and a directional valve (4) and a compensation valve (9). A compensation valve (9) is arranged after the directional valve (4) in the flow direction and a pressure relief device (43) is arranged between the directional valve (4) and the low-pressure connection (T).

Abstract: A hydraulic valve system (1) has a supply connection arrangement, having a high-pressure connection (P) and a low-pressure connection (T), a working connection arrangement, having two working connections (A, B), which can be connected with a hydraulic motor (2), and a directional valve (4) between the supply connection arrangement (P, T) and the working connection arrangement (A, B), which is connected with the working connection arrangement (A, B) via working lines (17, 18), in which are arranged check valves (21, 22), which can be opened by means of pressure.

Abstract: A non-feedback proportional system is provided to achieve desired operating characteristics which will allow the control of a hydrostatic transmission to closely approximate the control performance of a displacement feedback control system by establishing certain parameters relating to (1) the servo spring rate; (2) the valve plate index; (3) valve plate crossport/trap; (4) valve plate porting geometry; (5) swashplate offset; and (6) piston bore volume.

Abstract: A hydraulic steering system (1) with a supply connection arrangement, having a high-pressure connection (P) and a low-pressure connection (T), and with a working connection arrangement (L, R), a directional valve (2) and a metering pump unit (3, 4) being arranged between the supply connection arrangement and the working connection arrangement, the metering pump arrangement having at least two hydraulically parallel-connected and mechanically parallel-operated metering pumps (3, 4) with a shut-off valve (6) in a hydraulic connection between the two metering pumps (3, 4), said shut-off valve (6) having a return spring (16) and a first control inlet (15) that is connected with the high-pressure connection (P).

Abstract: A hydraulic control system (1) has a hydraulic motor (10), which is connected with a control valve (2) via two working lines (8, 9), the control valve (2) being connected with a low-pressure connection (T) and, via a compensation valve (4), with a high-pressure connection (P), to ensure that a return compensation valve (14, 15) is arranged in each working line, each return compensation valve (14, 15) having a nominal flow line (29), which extends unintersectedly in relation to the nominal flow line (28) of the compensation valve (4).

Abstract: A clamp for connecting a cylindrical temperature sensor axis-parallel with a tube has a bendable metallic tension band which tension band on its one end portion has a first jaw and at its other end section is shapewise connectable with a second jaw, and which clamp also has a tension screw. The tension screw is inserted through a bore in the first jaw and is threaded through a threaded bore in the second jaw. To be able to connect the sensor and tube rigidly with little heat transfer resistance the second jaw has a bent plate with two legs. The first leg is provided with the threaded bore and the second leg with a slot through which the other end section can be passed. The tension band length is so chosen that the other end section after the wrapping of the tension band around the temperature sensor and the tube as well as its being passed through the slot is bendable down onto the second leg. The tension screw length is so chosen that after its tightening it lies on the bent down end section.

Abstract: A hydromechanical transmission has a housing with a planetary gear system. A power output is operatively connected to the gear system for deriving power therefrom. A control is provided for operating the gear system in either a hydromechanical or a hydrostatic mode.

Abstract: A control device for the position (x) of a valve slide (3), with a d.c. voltage (UB) operated set point transmitter (11), which produces a set point value (Uw) proportional to the position (w) of a control lever (10) and the operating d.c. voltage (UB), with an actual value transmitter (15) operated with the same d.c. voltage (UB) as the set point transmitter (11), which produces an actual value signal (Ux) proportional to the position (x) of the valve slide (3) and the operating d.c. voltage (UB), the proportionality factors (k1, k2) being equal to the dependence of the set point and actual value signals (Uw, Ux) on the position (x) of the valve slide (3) or the position (w) of the control lever (10), respectively, and on the operating d.c.

Abstract: The invention relates to a refrigerant compressor comprising at least one piston-cylinder unit and one valve plate that has at least one outlet opening. The piston has a projection which projects into the outlet opening when the piston is located near the upper dead center thereof. The aim of the invention is to increase the efficiency and to reduce the noise level. To these ends, the invention provides that the outlet opening, piston projection, valve plate and piston delimit a flow channel, and provides that the free cross-sectional area of the flow channel is determined by the smallest cross-sectional area of the outlet opening until the piston, during its pressure stroke at least the height (H) of the outlet opening, is located underneath the upper dead center.

Abstract: A swing cylinder oscillation control circuit and valve for oscillating booms connects two hydraulic cylinders with a shuttle valve and two check valves to provide the higher cylinder pressure to a fluid inlet and a lower cylinder pressure to a fluid outlet of a fast-opening and a slow-closing check valve. The fast-opening and slow-closing check valve uses a poppet and spring to set a valve opening pressure and uses internal flow connections to a large diameter piston that works with mechanically adjustable piston and poppet strokes to control the time for valve closing.

Abstract: A hydraulic power unit in a housing has a power shaft associated with the power unit. A transducer adapted for measuring torque is mounted in the housing. A stationary portion of the transducer is mounted in non-contact relation to the shaft. A method for measuring torque in the power unit involves placing the transducer in the position described.

Abstract: The invention concerns a hydraulic machine (1) with a tooth set (2), having a gear wheel (3), which is arranged to be rotating and orbiting in a toothed ring (4), the tooth set (2) being arranged between two plates (10, 11) in the axial direction. It is desired to extend the life of such a machine, also when operated with an impurified hydraulic fluid. For this purpose, at least a section (9′) of the circumferential surface of one of the two components, toothed ring (4) and gear wheel (3), is made of a material, which is substantially harder than the material of the part of the other component, gear wheel (3) and toothed ring (4), bearing on this section.