Abstract: A control arrangement for lifting and lowering a hydraulically operated implement comprises a precontrolled reversing valve and a precontrolled stop block arranged in the fluid pressure stream leading from a source of fluid pressure over the reversing valve to the compartment of a cylinder and piston unit connected to the implement for lifting the latter during feeding of pressure fluid into the compartment and for lowering the implement during discharge of pressure fluid from the compartment. The stop block comprises a releasing piston cooperating with a stop valve of the stop block to alternatingly connect the compartment to a return conduit leading to a tank to discharge pressure fluid from the compartment or to the reversing valve to feed pressure fluid into the compartment. A pressure valve arranged in the releasing piston controls a connection leading from the reversing valve to a damping chamber at one end of the releasing piston which is additionally influenced by the movement of the latter.

Abstract: A regulating device for a working cylinder of an agricultural vehicle comprises a directional multiway control valve which controls the flow of a working fluid to the cylinder via a switch valve which is normally biased into its closing position and held in its open position by a pressure difference applied thereto from a throttle arranged in a main control conduit connected to a control fluid pump. One end of the spool of the directional multiway control valve is spring biased into a lowering position and its other end is controlled by a setting cylinder which in turn is controlled by an adjustment pressure having an actual pressure component and a desired pressure component. Means for setting the adjustment pressure includes an adjustable pressure reducing valve connected in series in the main control conduit with an adjustable pressure relief valve, the adjustment means of the latter being controlled by an actual power measuring unit on the vehicle.

Abstract: A control arrangement for a hydraulic power transmission comprises a main valve slide, a precontrol valve slide for controlling the main valve slide, as well as an auxiliary valve slide for controlling flow of pressure fluid through a pressure channel leading from a pump to a hydraulic consumer, for instance to fluid operated cylinder and piston means. The arrangement includes further a control conduit branching off from the pressure channel and leading over a throttle, the precontrol valve slide and the auxiliary valve slide, in which the latter is movable between two end positions under the influence of a spring and the hydraulic pressure in a pressure chamber and arranged to control passage of fluid through the control conduit, and two adjustable throttles in the control conduit, respectively formed by the auxiliary valve slide and the precontrol valve slide.