Abstract: An arrangement for mechanical measurement and for regulation of a pulling force of a tractor, has a bending-elastic element whose bending is sensed by a sensing device which acts on a lifting device for a three-point linkage of the tractor, wherein the bending-elastic element is formed as a pin which is hollow and supports one link of the linkage between two housing-fixed bearing points, and the sensing device has a gauge stick which extends inside the pin substantially between both housing-fixed bearing points.

Abstract: Hydraulic control arrangement for a driven working device particularly mounted on an agricultural vehicle, comprises a hydromotor for driving a working device, a blocking unit having a blocking valve and a pushing piston, a control valve including a control slider which controls the blocking unit and has three control edges, and a control chamber, two working chambers, and two return chambers, a throttle valve having a throttle slider and a spring arranged in a chamber and loading the throttle slider, a working conduit leading from an inlet via the throttle slider, the first control edge of the control slider and the blocking valve to the hydromotor and allowing a load pressure-independent control, a control conduit branching from the working conduit and extending via the third control edge of the control slider, the control chamber and the second return chamber to a tank, and supplied with a control pressure medium in a lowering position of the control slider via the throttle slider, and two throttle points

Abstract: A hydraulic control arrangement for regulating a lifting device in an agricultural vehicle has a proportionally operating regulating directional valve which includes a blocking unit, a control slider controlling said blocking unit and connected with a throttling valve so that its throttle slider during lifting operates as a pressure compensation valve and during lowering as a pressure reducing valve, and a spring associated with the throttle slider is only insignificantly stronger than the regulating spring in an adjusting device of an adjusting pump, so that during actuation of the throttle slider depending upon the high load pressure of a parallel-operating second hydromotor, the pressure differential required for the lifting stream at the control slider and the pressure differential acting during lowering in the first control conduit remain substantially constant.

Abstract: A control arrangement for a hydraulically operated load lifting and lowering device includes precontrolled first valve means controlling flow of fluid from a source under pressure to a return conduit leading to a tank or to a working conduit leading to the device and a closer block in the working conduit, including a piston controlling flow of pressure fluid from the working conduit into the device, respectively flow of pressure fluid out of the device into the return conduit downstream of the piston. A throttle is arranged in the return conduit to produce upstream of the throttle a pressure acting on the piston but not on the slide of the first valve means, whereby without increasing the neutral fluid circulation pressure a uniform lowering of the load independent of the magnitude thereof may be obtained.

Abstract: A control arrangement for a hydraulic power consumer particularly in agricultural machines, has a pressure medium reservoir which is connected with a member for supplying pressure medium from the reservoir to the consumer to thereby move the consumer in one direction. The consumer is also connected with a member for withdrawing pressure medium from the consumer to thereby move the latter in an opposite direction. The arrangement further includes a single valve unit which is operative for both communicating and discommunicating the consumer with the supplying member and with the withdrawing member to thereby alternately move the consumer in the respective directions.

Abstract: A control apparatus for a hydraulic power consumer, particularly in agricultural machines, has a pressure medium reservoir which is connected with a member for supplying pressure medium from the reservoir to the user to thereby move the latter from a stationary position. This member is subject to pressure oscillations which result from a pressure difference which is created in this chamber on displacing of the consumer from the stationary or neutral position. In order to eliminate undesirable oscillations of the user on displacement of the latter from the stationary position the arrangement is provided with a member for damping these pressure oscillations.

Abstract: A control arrangement for a hydraulic force transmission, especially for a hydraulically operated lifting device on agricultural vehicles comprises, besides a main control slide, a pressure control slide and a blocking device, an auxiliary slide arranged in a bore of the pre-control slide. The hydraulic working fluid is fed from the main slide directly to the blocking device and a special arrangement of the auxiliary slide in the hydraulic control circuit permits a compact and simple construction of the control arrangement, while preventing tight throttling of the fluid in either direction of the flow.

Abstract: A check valve with pilot actuation for hydraulic systems has a valve housing with a main bore and main seat, a main valve member movable in the main bore between a closed position and an open position and having an additional inner bore with a conical mouth at one end thereof, a pilot valve member movable between a closed position and an open position in said additional bore, and a push rod operative for moving the pilot valve member to the open position thereof. The push rod has a first thinner portion and the second thicker portion forming a shoulder. A conical transitional portion is formed between the above two portions and is complementary to the conical mouth of the bore of the main valve member. The push rod has pressure-relief clearances formed in the region of the transitional portion and the shoulder, and so located that when the transitional conical portion is seated on the conical mouth fluid in said additional bore can pass through the clearances.

Abstract: A valve arrangement in which a follower is mounted on one end portion of a first valve member which extends into a space formed in a housing of the valve arrangement. The follower cooperates with a second valve member in a bore of the housing parallel to the bore in which the first valve member is reciprocatable. The bore in which the second valve member is arranged comprises a valve seat engageable by a portion of the second valve member, which is spring-biased in a direction in which the aforementioned portion thereof engages the valve seat, and the follower is arranged to move the portion of the second valve member away from its valve seat when the first valve member is moved in its bore in a predetermined direction.