Abstract: A feed circuit for feeding a railway train braking system and usable in conjunction with a compressed air system or with a vacuum system, the feed circuit including an air compressor (1) and being characterized in that it further includes a static vacuum pump (14) powered by the compressed air delivered by the compressor.

Abstract: A brake system for automotive vehicles is disclosed comprising a vacuum brake force booster operatively located between a brake pedal and a master brake cylinder. The vacuum brake force booster includes at least two working chambers separated from one another by a membrane plate, one of the working chambers, through a master magnetic valve, being in communication with a vacuum source and the other working chamber being vented through a control valve acutable by the brake pedal to generate a brake force proportional to the brake pedal force. Connected to the master brake cylinder are brake circuits applying pressure to the wheel brake cylinders. Sensors associated with the wheels detect the rotational behavior of the wheels to identify a locking condition.

Abstract: In order to reapply the fluid operating pressure to the braking members of the wheels after an anti-locking operation has been carried out, a pumping device is provided which are driven by the subatmospheric pressure (vacuum) existing in the inlet manifold of the engine. The application of the braking pressure is controlled by a valve which receives an opening command signal consisting of a train of pulses from a control device. At least one vacuum sensor is provided which generates a monitoring signal indicative of the level of vacuum present in the inlet manifold. The control device causes opening of the valve with a command signal whose average is inversely proportional to the level of the monitoring signal generated by the vacuum sensor.

Abstract: In the vacuum boosting system for the brake of a vehicle wherein the boosting vacuum is supplied from the intake manifold of the engine and also, as an assistance thereto, from a vacuum pump which is to be occasionally operated when the intake vacuum of the engine is insufficient to boost the brake, the operation of the vacuum pump is controlled in two alternative modes. In the first mode, when the vehicle is running at a relatively high speed with the transmission being shifted to a relatively high speed stage, the vacuum pump is switched on when the brake boosting vacuum has dropped below a first relatively high threshold value to be operated for a first relatively short period so as to recover the vacuum.

Abstract: Disclosed is a control for pumping devices in vehicle application. Upon closure of a brake actuator switch (4) subsequent to actuation of a power switch (6) a power transistor (81) becomes conductive and a DC voltage from batteries (5) is fed to a DC motor (2). The brake actuator switch when brought into an open position permits supply of the DC voltage to the base of the power transistor through a time constant circuit (85, 86) for a limited period of time, so that the power transistor becomes conductive to supply the DC voltage to the DC motor for that period. The DC motor activates a pump (1) which in turn operates a pressure-operating unit (10).

Abstract: A control device for a vacuum pump apparatus in which a hunting effect is substantially eliminated. A pressure-sensitive switch senses a negative pressure produced by a vacuum pump, the latter being driven by a d.c. motor. The switch has at least three contacts, the positions of which are changed at two different pressures. The output of the switch is compared with a fixed reference value, and the comparison result used to drive the d.c. motor. The d.c. motor is thus provided with hysteretic drive characteristic, thereby maintaining the vacuum pressure between the two predetermined values and eliminating the hunting effect.

Abstract: A supplemental brake system operates in cooperation with a motor vehicle's extant emergency brake system for selectively slowing a spinning wheel. A selector valve communicates with the vehicle's vacuum system and conduits are sized to cause a delay in the slowing of the spinning wheel. Further, the system provides for the gradual extension of the emergency brake cables which is unaffected by changes in vacuum levels in the vacuum system. The operator has full control of the vehicle during the system's operation.

Abstract: A control system for a diaphragm vacuum pump comprises a vacuum sensor disposed within the vacuum chamber of a pneumatically operated device for detecting a predetermined vacuum pressure to ensure the effective operation of the device and generating an output signal therefrom. A switchover solenoid valve is disposed within the pneumatic connection between the suction port of the vacuum pump and the vacuum chamber of the device is energized in response to the output signal of the sensor to selectively open the pumping chamber of the pump to the air through the suction port and close the vacuum chamber of the device.