Abstract: A compound electropneumatic brake control system which has a compound brake power command controller for controlling an electric brake system and a fluid brake system on motor cars and trailer cars. A plurality of motor and trailer car weight setters and a plurality of signal summing networks which cause any brake deficiency is either supplemented by both the fluid brake systems on the motor cars and trailer cars or is initially supplemented by the fluid brake system on the trailer cars and then is subsequently supplemented by the fluid brake system on the motor cars.

Abstract: A vital low frequency code generating circuit having a pair of complementary unijunction transistor relaxation oscillators for producing coincidental pulses in the absence of any failure; and a first initially nonconductive transistor amplifier and a second initially conductive transistor amplifier for saturating a square loop core transformer in a positive direction. The coincidental pulses causing the first transistor amplifier to be rendered nonconductive to unsaturate the square loop core transformer and causing the second transistor amplifier to be rendered conductive to saturate the square loop core transformer in the negative direction, which results in the development of output code pulses only when neither of the relaxation oscillators has drifted appreciably.

Abstract: A solenoid-operated fluid control valve having manual override and fluid latching for establishing a fluid path between a supply port and a delivery port when a brake-release solenoid pilot valve coil is momentarily energized to cause a pilot piston to close an exhaust valve and to open a supply valve for causing feedback pressure to be fed from a delivery chamber to a pilot chamber for fluid latching the pilot piston in a brake-release position until a brake-application solenoid pilot valve coil is momentarily energized which causes the pilot chamber to exhaust to atmosphere so that the pilot piston returns and opens the exhaust valve and allows the closure of the supply valve.

Abstract: The invention relates to an electropneumatic coupling arrangement for providing a pressure-tight connection between a pressure supply line and a pressure chamber of a hydropneumatic component. The coupler includes a plastic plug-in body member having a pressure conduit and a plurality of electrical contacts for interconnecting an electrical sensing element located in the housing of the hydropneumatic component to apparatus located outside the hydropneumatic component.

Abstract: A vehicle gearshift selection system for a multiple-speed power-assisted transmission having a gearshift lever which is shiftable into a single shift-up position or a single shift-down position. A gear sensor for monitoring the position of the gearshift lever and connected to an evaluation control circuit. The electronic evaluation control circuit is connected to the multiple-speed power-assisted transmission and receives signals concerning the prevailing driving conditions of the vehicle for engaging an optimum higher gear when the gearshift lever is shifted-up and for engaging an optimum lower gear when the gearshift lever is shifted-down.

Abstract: A multiplex cabling system for controlling electrical apparatus on motor vehicles, which consists of a central transmitter and several area transmitter-receivers, each connected to several controlled devices and/or indicators. Coupling between the central transmitter and the area units is made by a star-arranged line system which consists of a separate, two-wire connecting channel between the central transmitter and each area transmitter-receiver. To further increase the system's reliability and security, the central transmitter includes two microprocessors which are normally assigned to control a different pair of diagonally-opposite area transmitter-receivers. If one processor fails, the other unit assumes full system control.

Abstract: A load compensating valve for a compressed air brake system for railroad vehicles having air spring devices. The load compensation valve includes a supply chamber and an output chamber which are interconnected by a supply valve and an exhaust valve. A balance piston responsive to air spring pressure for controlling the pressure in the output chamber. A check valve disposed in parallel with the supply valve to allow the output chamber to discharge when the supply chamber is exhausted.

Abstract: A pneumatically controlled double seat relay valve including a housing for accommodating a reciprocating control piston having a first reactive surface acted upon by a source of control pressure and having a second reactive surface acted upon by a source of working pressure. A spring biasing valve piston slidably disposed in a tubular projection formed in the control piston. A spring biased slidable valve member disposed in a central bore formed in the housing and including an inlet valve cooperatively associated with an inlet valve seat formed by an annular lip of the central bore. An outlet valve seat carried by the slidable valve member and cooperatively associated with one side of the valve piston to initially close the outlet valve and subsequently open the inlet valve when control pressure is applied to the first reactive surface and for allowing the inlet valve to close when working pressure is applied to the one side of the slidable valve member to overcome the spring bias.

Abstract: An F.M. demodulator of the phase quadrature type is adapted for fail-safe operation and in particular for use in a railway signalling system. A Bessel band-pass filter is chosen for the design basis of the phase delay arm, its characteristics, failure modes and resulting effects are considered and the design adaptations required to avoid the potentially unsafe effects of failures are determined. Due to loss of failure in the unmodified filter design the slope of the phase characteristic can increase effectively broadening the filter bandwidth and reducing attenuation of out-of-band signals which could, as a result, provide a false output. The demodulator may be combined with a fiber-optic link to form part of a complete signaling transmission system.

Abstract: A vital integrated circuit square-wave oscillator having an integrated circuit operational amplifier. A reference voltage dividing resistor network connected to an inverting input of the amplifier for providing a 50--50 duty cycle. An L-C tank circuit connected between the inverting input and a noninverting input for determining the frequency of oscillation. A starting capacitor for initiating the oscillating action and a regenerative feedback circuit for sustaining the oscillations.

Abstract: A compressed air brake system including a low pressure control circuit and a high pressure operating circuit. The control circuit is interfaced by a plurality of relay valves with the operating circuit for the direct actuation of the wheel brake cylinders with high pressure. The dual pressure arrangement results in a significant reduction in consumption of air while retaining the advantages which are common to a high pressure system.

Abstract: A pressure gas generating system including the compressor which is switched to a no-load condition when a predetermined pressure level is reached. The system employs either a regulator or a governor to allow the free exchange of gas between the suction chamber and the compression chamber to prevent the development of high temperatures. In the pressure regulator control system, the opening of the discharge valve is enlarged and is vented into the atmosphere by the pressure regulator so that the compressor continues to operate with reduced drive power and generates less heat during the no-load condition. In the pressure control system, the pressure discharge valve as well as the suction valve are opened during the no-load condition.

Abstract: An arrangement for checking the integrity and operability of a semiconductive device including a control circuit for injecting test signals into a normal control signal to induce a momentary change of the operating condition of the semiconductive device, a sensing circuit connected in parallel with the semiconductive device sensitive to an induced change to produce an output indicating the induced change, and a correlation circuit operative to correlate the test pulses with the sensed response which is arranged to carry out predetermined action in the event that the correlation circuit determines a state of inoperability of the semiconductive device.

Abstract: An arrangement for providing electrical remote control of several magnetic solenoid valves having a transmitter section and a receiver section. The transmitter includes a fixed frequency signal generator for producing signals having an adjustable duty cycle. The duty cycle of the periodic signals varies in accordance with the position or deflection of an adjustable control lever. The periodic signals are transmitted over a first transmission link to the receiver section for controlling the condition of the magnet valves. A second transmission link is utilized for transmitting digital coded address information concerning which of the magnetic valves is to be selected in the receiver section in accordance with the position of the control lever in the transmitter section.

Abstract: A fluid pressure operated mechanism for a vehicular disk brake which includes two expansion elements capable of moving in opposite directions to each other. A compensating unit located between the two expansion elements to maintain a given stroke of the expansion elements and eliminate excess play which may be developed as a result of brake lining wear. The compensating unit takes the form of a one piece connecting link having return spring portions engaging one of the expansion elements and frictional gripping portions connected to the other of the expansion elements.

Abstract: A pneumatic vigilance monitoring system which requires an engineer of a moving train to cycle an acknowledging valve within a predetermined time after the sounding of a warning whistle. The system includes a pair of parallel control circuits each having a first choke and reservoir and a second reservoir and choke connected to the acknowledging valve. A double check valve connects the second reservoirs to the warning whistle as well as to a piloted three-way valve which normally causes a brake application valve to release the brake and which causes the brake application to initiate a penalty brake application if the locomotive engineer fails to periodically cycle the acknowledging valve.

Abstract: A Hall effect element, incorporated into an integrated circuit unit with temperature compensation, voltage regulation, and amplification, is mounted on top of a permanent magnet made of ceramic material with the critical Hall axis aligned with the magnet pole axis. To avoid saturating the Hall cell, it is positioned within a pole-to-pole hole in the magnet, which creates a flux null space. The permanent magnet and Hall cell assembly is mounted on the rail a predetermined distance below the top so that the flange of passing wheels occupies the air gap between the magnet and the rail through which the major portion of the magnet flux flows. Reduction of the air gap increases the level of the magnet flux and thus the level of voltage output of the Hall cell. The output of the Hall cell is applied to a Schmitt trigger whose switching level is set by a threshold voltage unit.

Abstract: A reciprocating piston compressor which is driven by a rotating camshaft and cam. An auxiliary piston is located below the compression piston. The auxiliary piston is movable by a regulated control pressure against the compression piston so that the compression piston is stopped at its top dead center position. Thus, the reciprocating piston compressor is disabled since the compression piston is no longer driven by the rotating camshaft and cam.

Abstract: A pressure gas generating system including the compressor which is switched to a no-load condition when a predetermined pressure level is reached. The system employs either a regulator or a governor to allow the free exchange of gas between the suction chamber and the compression chamber to prevent the development of high temperatures. In the pressure regulator control system, the opening of the discharge valve is enlarged and is vented into the atmosphere by the pressure regulator so that the compressor continues to operate with reduced drive power and generates less heat during the no-load condition. In the pressure control system, the pressure discharge valve as well as the suction valve are opened during the no-load condition.

Abstract: A vigilance safety control arrangement for periodically checking the attentiveness of a trainman. The arrangement includes a pair of capacitive charging circuits connectable to a source of voltage and a pair of resistive-capacitive discharging circuits connectable to an application and indication relay. An electrical toggle switch for periodically connecting one of the pair of capacitive charging circuits to the voltage source and one of the pair of capacitive discharging circuits to the application and indication relay for causing a magnet valve to maintain the brakes of the train in their released position.