Abstract: Driver brake valve for operating compressed air brakes of rail vehicles. An electropneumatic converter is used to generate a servopressure. The servopressure actuates a relay valve for pressurizing a main air line. An electronic regulation circuit receives a plurality of electrical control signals, including a signal proportional to the pneumatic servo-pressure. The regulation circuit generates an ideal value signal for controlling the electro-pneumatic converter and controls the starting behavior of the brake system. Brake demands which exceed a threshold value are applied to the electronic circuit which generates the ideal value signal. Pressure sensors connected to the main air line and a flow sensor connected to a main container line are used to derive the ideal values for controlling the pneumatic servopressure and the operation of the relay valve.

Abstract: A sanding apparatus for a vehicle, particularly rail vehicles, has a sealed container for sand and the container is provided with a bottom wall which is permeable by air. A sand discharge pipe extends from the container through the bottom wall and has an end position in front of a vehicle wheel. An air supply line extends from a source of air under pressure and opens into a chamber underneath the bottom wall of the container. An exhaust air line has one end within the container above the level of sand when the container is full and has its other end connected to the sand discharge pipe. The flows of air through the air supply line and the exhaust air line are so controlled that at a predetermined pressure of supplied air a remaining portion of the supplied air flows through the sand discharge pipe at a rate to discharge a predetermined quantity of sand per unit time from the sand discharge pipe. Various structures are provided for regulating these flows of air.

Abstract: A valve device for controlling pressure medium actuated brakes, particularly for railway vehicles, comprises a multi-stage valve to set one of a plurality of pressure stages. The valve has an axially displaceable stepped piston having a plurality of annular radial surfaces with a predetermined surface area ratio to each other. The surfaces are subjected to the action of pressure medium through control valves separately or in combination in accordance with a selected pressure stage. The piston controls a double valve connected between a source of pressure medium and the brake which is supplied with pressure medium or vented in response to position of the double valve. The radial surfaces of the piston are subjected to a selected stage pressure against a constant force that is independent of the control pressure such that this axially applied force is in balance with the force exerted by the pressure of the pressure medium against the radial surfaces at every braking stage.