Abstract: A mass flowmeter has a flow-through channel (2) and as its measuring section (10) a thin strip (3) which at one end has an oscillation generator generating waves travelling along the measuring section (10) and at the other end has an energy converter (8, 9) acting as oscillation detector for these travelling waves. An evaluating circuit (11) determines the mass flow on the basis of the travelling speeds which are different in and against the direction of flow (X). In particular, only one measuring section (10) is provided, the energy converters (8, 9) of which are operable alternately as oscillation generator and oscillation detector. In this manner, meters of relatively short length and high accuracy can be made.

Abstract: A hydraulic machine is disclosed, with a gearwheel, which has a midpoint (6) and a predetermined number of external teeth, and an annular gear, which has a midpoint (7) offset by an eccentricity (E) with respect to the midpoint (6) of the gearwheel and a number of internal teeth which exceeds by one the number of external teeth, the gearwheel and annular gear orbiting and/or rotating relative to one another and at least the form of the external teeth being created using a set of circles (30, 30'; 35, 35') lying with their midpoints (P1-P6; P1'-P6') on a trochoid (36, 37). It is desirable for the efficiency, service life and noise properties of such a machine to be improved. To that end, at least two trochoids (36, 37), displaced relative to one another in the circumferential direction, are provided for generating a tooth profile, the rolling circles (28, 33) of which and the base circles (27, 32) of which differ from one another.

Abstract: A hydraulic piston machine is proposed, with a cylinder body (1), which comprises at least one cylinder (2) with a piston (3) movable therein, and a control counter-plate (7) which engages the cylinder body (1) by way of a contact surface (6) and, on relative movement between the cylinder body and the control counter-plate parallel to the contact surface, connects the cylinder in dependence upon its position with inlet and outlet channels (11, 12) respectively, the control counter-plate (7) and/or the cylinder body (1) being provided, at least in the region of the contact surface (6, 9), with a friction-reducing layer (13). A machine of that kind should be inexpensive to manufacture yet should operate reliably even when the hydraulic fluid has no or only slight lubricating properties. For that purpose the friction-reducing layer (13) is in the form of an injection-moulded part.

Abstract: An operating device (1) with a top part (2) having an actuating arrangement (5) and a bottom part (3) carrying the top part (2). The top part (2) and bottom part (3) are releasably joined to one another and the actuating arrangement (5) drives a control member (6). In an operating device of this kind it is desirable for the top part (2) to be easily mounted on the bottom part (3) and to be easily detachable therefrom. For that purpose the top part (2) and the bottom part (3) are joined to one another by a bayonet joint (16,18).

Abstract: A hydraulic machine with a piston and slider shoe unit (1) is disclosed, in which the piston (2) and the slider shoe (3) are joined to one another by way of a ball-and-socket joint (4) forming a first contact surface, and the slider shoe (3) lies via the intermediary of a second contact surface on a control surface (9), a friction-reducing layer being arranged on one contact surface. It is desirable for a hydraulic machine of the that kind to be capable of reliable operation even when using hydraulic fluids having only a operation even when using hydraulic fluids having only a poor or no lubricating effect at all, yet to be inexpensive to manufacture. For that purpose, the friction-reducing layer (11) is extended to at least one further contact surface.

Abstract: A hydraulic axial piston machine (1) is disclosed, having a cylinder drum (2) which is mounted rotatably in a housing and comprises at least one cylinder (3) which, on rotation of the cylinder drum (2), passes over control kidneys (15) in a control face. In order to be able to operate such a machine even with hydraulic fluid that has no or only slight lubricating properties, such as, for example, water, and in order to be able to manufacture the machine with few manufacturing steps, the control face is located on the rear flange (9) of the housing, and the control kidneys (15) are formed in a plastics material insert (10) which is arranged in the rear flange (9) of the machine (1).

Abstract: A hydraulic machine is disclosed, having an annular gear with internal teeth and a gearwheel with external teeth mounted eccentrically therein, the internal teeth comprising one more tooth than the external teeth and the teeth of at least one set of teeth being formed by rotatably mounted rollers. It is desirable in such a machine for the internal seal to be improved and wear to be reduced. To that end, each roller has in its surface at least three axially parallel recesses, in which the teeth of the other set of teeth engage.

Abstract: A hydraulic steering arrangement for vehicles is proposed, with a steering motor, a flow amplifier in fluid connection therewith, which amplifies a fluid flow measured by a steering measuring device, at least one sensor, which determines a performance characteristic of the vehicle, and a control device, which changes the amount of fluid supplied to the steering motor in dependence on an output signal of the sensor. In a steering arrangement of that kind, it is intended to correct or adapt the steering behavior to the operational status of the vehicle using simple means. For that purpose, the control device changes the amplification factor of the flow amplifier.

Abstract: A hydraulic axial piston machine is disclosed, having an inclined plate (7), on which a slider shoe (9) of at least one piston slides on relative movement between a cylinder body (2) receiving the piston and the inclined plate (7), and a pressure plate (10) articulated on the cylinder body (2) and holding the slider shoe (9) in engagement with the inclined plate. It is desirable for such a machine also to be operable with a hydraulic fluid that has no lubricating properties. For that purpose, between the pressure plate (10) and the cylinder body (2) there is arranged a bearing element (18) with a bearing surface (19) of plastics material, which slides with low friction on a counterpart (15) made of metal lying against the bearing surface (19).

Abstract: A slanting plate arrangement in a hydraulic axial piston machine is disclosed, having a slanting plate and a pressure plate, between which at least one slider shoe of a piston axially movable in a cylinder body is held, the pressure plate being rotatably connected to the slanting plate by means of an axle element limiting axial movement of the pressure plate with respect to the slanting plate in at least one direction. It is desirable to be able to use such a slanting plate arrangement even when a hydraulic fluid that has no or only slight lubricating properties is used. For that purpose, in the region of contact between the axle element and the pressure plate and/or axle element and slanting plate, a material combination of a metal and a high-strength thermoplastic plastics material is provided.

Abstract: A solenoid valve assembly having a rapid assembly clip. The clip is a spring clip which is pivotally secured to a housing for the solenoid valve assembly. The clip engages an annular groove in an extending portion of a solenoid element, with the clip being appropriately shaped to engage the groove to retain the solenoid element in place in the housing. In the described form of the invention, the spring clip is a wire element which engages the annular groove on opposite sides. Where there is engagement, the wire element is curved to conform to and firmly seat in the annular groove.

Abstract: A valve with presetting facility has a valve housing with a rotatable sleeve. To form a present throttle, a control opening at the base of the sleeve co-operates with a control opening at a base face of the valve housing. The control opening in the base face is formed by an eccentric bore. The control opening in the end face of the base is formed by a channel which extends over a circular arc of less than 360.degree. , is connected at one end by way of an eccentric bore to the inner space of the sleeve and has a cross section that reduces towards the other end. That allows presetting to be very precise and manufacture to be inexpensive.

Abstract: A hydraulic valve assembly configured for controlling the elevation and operation of a mowing deck of a power mower. The valve assembly includes a housing having a valve spool positionable in four positions, a cylinder activation position, a neutral position, a cylinder relief and motor start position, and a motor run position. In the cylinder activation position pump pressure is connected to a deck raising cylinder. In the neutral position, a status quo is maintained, and pump is vented to tank. In the cylinder relief and motor start position, the mowing deck, if elevated, is lowered under its own weight by relieving pressure on the deck cylinder, and the mowing motor is started in operation under low pressure. In the motor run position, the motor is connected to high pressure, and the deck cylinder continues to be vented to tank.

Abstract: A deforming tool having a die and prestress ring for the extrusion of a workpiece. The prestress ring being constructed so that the radial prestress exerted by it on the die in a region of transition from one to the other of two converging inner faces of the die, which together form an internal angle of less than 180 degrees, and/or in the region of a sudden transition from a low to a high value of the pressure exerted by the workpiece during its deformation radially on the die, is less than in the regions adjacent to the transition.

Abstract: A hydraulic piston machine is disclosed, having a cylinder drum and a control plate, which control plate has at least one high-pressure "kidney" and at least one low-pressure "kidney" and also a contact surface against which the cylinder drum bears in operation, at least the contact surface being provided with a friction-reducing layer. It is desirable for such a machine to have better operational behavior and a longer service life. For that purpose, the contact surface in the region of the low-pressure kidney has a recessed region forming a gap between the cylinder drum and the control plate.

Abstract: A hydraulic axial piston machine is disclosed, with a cylinder drum (2), which has at least one cylinder (3), in which a piston (6) is mounted so as to be axially displaceable, and with a control counter-plate (11 ) which, on rotation of the cylinder drum (2) and the control counter-plate (11 ) relative to one another, connects the cylinder (3) in dependence upon its position with a fluid inlet (14) and a fluid outlet (15). With a machine of that kind, it is desirable to improve balancing out of the forces necessary for effecting a seal between the cylinder drum (3) and the control counter-plate (11). For that purpose, between the cylinder drum (2) and the control counter-plate (11 ) there is arranged a pressure plate (17) which engages the cylinder drum (2) via the intermediary of a spring element (21), the pressure plate (17) having a through-opening (20) associated with the cylinder (3), which through-opening is connected to the cylinder (3) in a fluid-tight manner.

Abstract: An axial piston machine (1) is described, having a cylinder body (2) that is rotatable relative to a wobble plate (3) and in which several pistons (6) are arranged so as to be axially displaceable, the pistons being supported on a sliding-contact face (4) of the wobble plate 930 by means of slider shoes (9) articulated at the free ends of the pistons, wherein a pressure element (13) holding the slider shoes (9) on the sliding-contact face (4) is provided. It is desirable to reduce internal leakage in an axial piston machine of that kind. For that purpose, a wave spring element (16) is provided between each slider shoe (9) and the pressure element (13).

Abstract: A fault-tolerant reluctance motor has a multi-phase stator winding. The stator has a different number of poles from the rotor. The lead angle and the pole angle (.beta..sub.s, .beta..sub.r) embraced by each stator and rotor pole is at least the same as twice the step angle ##EQU1## where q is the number of phases and N.sub.r is the number of rotor poles. In particular, the stator has ten poles, the rotor has six poles and the stator winding has five phases. Such a reluctance motor starts up from any motor position in one or other direction of rotation, even when one of the phase windings is completely or partially ineffective owing to a fault.