Abstract: In a mixed medium brake system for a motor vehicle, there is provided a hydro-pneumatic brake cylinder device in a common housing having a compact configuration that is realized by designing the hydraulic piston in the form of a cylindrical plunger having a hollow cavity in the end adjacent the pneumatic piston, whereby engagement of the pneumatic piston push rod with the plunger is at a location thereof forward of the end adjacent the pneumatic piston, thus minimizing the distance required between the pneumatic piston and the hydraulic piston formed by the plunger. Such an arrangement also reduces the binding action of the cylindrical plunger in its guide bore for improved operation, while accommodating pivotal motion of said pneumatic piston.

Abstract: A hydro-pneumatic brake actuator arranged with a slack adjuster piston and one-way check valve device in the hydraulic path between a hydro-pneumatic actuator and a power piston, to which a friction brake element is connected for engagement with a vehicle wheel tread or brake disc during a brake application. During a brake release, the one-way check valve closes a passage through the slack adjuster piston to cause the piston to shift from its one extreme position to the other extreme position with the fluid flow, as the hydro-pneumatic actuator is moved from its application position to its release position. This in turn draws hydraulic fluid from the power piston chamber into a clearance volume created by shifting of the slack adjuster piston, and accordingly forces the power piston to retract a predetermined distance corresponding to the capacity of the clearance volume and the effective area of the power piston, thereby maintaining a constant brake shoe clearance during brake release.

Abstract: An improved vehicle wheel anti-lockup brake control system in which a shutdown signal is generated to disable the wheel anti-lockup control system in the event of a malfunction, as determined by the concurrent presence of a wheel slip signal and a low wheel speed signal (generated by the same wheel) for a predetermined period of time sufficient to allow a normally operative anti-lockup control system to correct a slipping wheel before it locks up.

Abstract: An antiskid control system for the individual regulation of fluid brake pressure at the respective wheels of a vehicle. The control system is modified so that a steering wheel experiencing high wheel/road adhesion is co-controlled during a cycle of wheel skid control at the steering wheel experiencing a low wheel/road adhesion value, such co-control being delayed at the onset of brake release at the low adhesion wheel, while the high adhesion wheel brake pressure is maintained constant to improve stopping distance.

Abstract: In a variable load valve device of the type employing a walking beam type lever arrangement via which the control and compensating pistons are interconnected to obtain proportional control of the brake pressure, there is provided an externally accessible screw adjustment for varying the tension of a bias spring acting on one of the levers, whereby the proportional brake control is withheld until a predetermined level of brake pressure is achieved corresponding to the spring bias.

Abstract: A vehicle load responsive control valve device in which the output pressure regulating valve assembly is controlled by multiple diaphragm pistons, which are arranged separately in tandem relationship and are operative responsive to the fluid pressure of different air springs of the vehicle. Being of equal pressure areas, these diaphragm pistons are effective to exert a control force on the valve assembly according to the higher of the respective air spring pressures to ensure against low brake forces when the pressure of one of the air springs is inadvertently lost under loaded car conditions. Under empty car conditions, a bias spring is effective to obtain a predetermined output pressure.

Abstract: A dual-circuit, hydropneumatic brake conytrol system having a load proportioning function wherein the load condition sensed at the rear axle establishes the braking level at both axles. The front axle brake control is adjusted through either a pneumatic or hydraulic connection with the rear axle load control device. By making the operator's brake valve hydraulic, it can be isolated from the remaining hydraulic and pneumatic brake control components, in order to minimize the amount of space required in the operator's cab to accommodate the brake valve.

Abstract: In a variable load valve device of the type employing a walking beam type lever arrangement via which the control and compensating pistons are interconnected to obtain load-dependent control of the brake pressure, there is provided a screw adjustment that acts through an auxiliary piston to vary the tension of a bias spring acting on one of the levers of the lever arrangement to bias the compensating piston in order to withhold the load-dependent brake control until a predetermined level of brake pressure is developed. The auxiliary piston is subject to brake control pressure supplied to the variable load valve inlet and in one embodiment of the invention, the auxiliary piston is formed to urge the piston in a direction to counteract the spring force and in another embodiment, to urge the piston in a direction to supplement the spring force.

Abstract: A variable load valve device having a piston subject to air spring pressure that varies with vehicle loading to position a cam member formed on a control piston in accordance with the vehicle load condition. The cam member acts through a plunger or push rod to operate a relay valve device via which brake pressure is controlled. A spring that acts on the control piston in opposition to air spring pressure has an adjustable deflection characteristic wherein a clamping device threaded within the spring coils is rotated by a screwdriver or the like. An adjustable screw that serves as a stop for the spring clamp member is provided with a through bore to accommodate passage of the screwdriver into engagement with a slot in the clamp member to facilitate rotation of the clamp, without requiring valve disassembly or component replacement.

Abstract: An operting handle assembly for actuating a valve or the like including an adjustable actuating cam member that controls the degree of deflection of the valve to obtain different output pressures for a given handle position, for example, and an adjustable friction brake mechanism that sets the desired tension for handle operation.

Abstract: A spring-applied, air-released parking brake, having a manual release mechanism with an automatic reset feature. To release a spring-applied parking brake, in the absence of air, a torsion bolt having a cam member formed on it is manually rotated to a position aligning the cam with an elongated slot in the piston push rod of the parking brake cylinder. This allows the piston to be extended in a direction to extend the spring, thus relieving the spring force. Reapplication of air pressure moves the piston push rod out of the elongated slot to permit angular rotation of the bolt by its torsion spring, so as to prevent its entry in the elongated slot until the bolt is again rotated manually.

Abstract: A wheel spin control circuit which utilizes conventional anti-skid control apparatus for automotive-type vehicles including an operator's brake valve, brake cylinders, wheel speed sensors, wheel behavior evaluation circuitry and modulator valves to apply braking pressure to a sensed spinning wheel. A solenoid-operated control valve in parallel with the brake valve between the system air reservoir and modulator valves is actuated via a pushbutton switch whenever the operator senses a spinning wheel during acceleration to connect reservoir air to the modulator valves. The modulator valve of the slipping wheel is actuated by control signals emitted by the wheel behavior evaluation circuit to admit the reservoir air to pass to the brake cylinder of the spinning wheel to effect braking thereof. The pressure supply may be continuous or pulsed with or without a pressure-holding cycle.

Abstract: A brake control system for a railway transit-type train having a control car, on which an electrical brake command is provided, and one or more controlled cars. The electric brake command is converted to a fluid pressure control signal that is connected to a load-adaptive relay valve device on the control car, as well as on each controlled car. Each load-adaptive relay valve is adjusted according to the load condition of a respective car so that the brake pressure of each car is developed consistent with its particular load and in accordance with the brake command in effect. In one embodiment of the invention, the electric brake command is a digital binary code formed by a three-wire control line and converted on the control car to a fluid pressure brake command signal by conventional electro-pneumatic valves and a multi-diaphragm relay valve device.

Abstract: A variable load valve device for modulating brake cylinder pressure on railway freight cars according to the actual vehicle load weight. A load sensing arm detects variations between the sprung and unsprung members of the vehicle to vary the tension of a pair of springs, one of which bias a proportioning valve to a normally closed position and the other of which biases a cut-off valve to a normally open position. The proportioning valve controls fluid pressure communication between the brake cylinder and a volume reservoir, such that when the proportioning valve spring tension is overcome by the brake cylinder pressure, the brake cylinder pressure will be modulated by flowing to the volume reservoir. By reason of the variable spring tension with load, the level of brake pressure at which modulation occurs increases with increased load so that the degree of brake pressure modulation reduces as the load increases.

Abstract: Brake apparatus for a railway vehicle including a brake cylinder device of the type having a pair of interconnected pistons to which the vehicle brake rigging is connected, the larger piston having a pair of chambers formed on opposite sides in which air is stored, and a control valve device that is operative responsive to a reduction of brake pipe pressure to connect pressure from the one side of the larger piston to a corresponding side of the smaller piston to effect movement of these pistons to a brake application position and concurrently vents pressure in the chamber on the other side of the larger piston. A transfer valve device is provided to interrupt this exhaust of pressure from the chamber on the other side of the piston until the piston has moved to application position so that the chamber volume is minimal and thus renders a minimum amount of air exhaust sufficient to produce brake applying pressure differentials across this larger piston.

Abstract: A process and apparatus for regulating the operator-controlled brake pressure of a vehicle wheel to prevent wheel lock-up by sensing a lock-up tendency and independently varying the operator-controlled brake pressure at the skidding wheel during successive cycles of wheel skid control. The sensed wheel behavior is monitored by an evaluation circuit which measures the duration of brake pressure reapplication with constant gradient during an initial cycle, provides a time period during a subsequent cycle that is a predetermined time duration less than the time duration of reapplication pressure in the initial cycle, and following expiration of the reduced time duration, establishes reapplication of pressure with a pressure gradient lower than the gradient during the initial cycle, whereby the reapplication pressure during control cycles subsequent to the initial control cycle is with a stepped gradient.

Abstract: An air-conditioning system in which a static inverter is driven at a predetermined constant frequency during a normal service mode of vehicle operation to effect operation of the vehicle cooling and/or heating unit such as to maintain the interior temperature of the vehicle within a chosen comfort zone. During initial start-up, when the interior temperature reaches extreme proportions due to the vehicle sitting in the sun or cold, an abnormal service mode of operation is called for in which the static converter is driven at an increased frequency and voltage for a predetermined limited time to rapidly bring the interior temperature within the comfort zone. The so-called abnormal service mode of operation may be indicated manually by the train service personnel under extreme temperature conditions after the start-up period of abnormal service mode has expired. Also provided is a passenger load sensing arrangement to increase the ventilation capacity of the cooling unit fans when overcrowding exists.

Abstract: This invention relates to a novel railway vehicle brake apparatus that comprises a brake cylinder device having two tandem-connected pistons of unequal size, the larger of which is provided with a check valve and cooperates with a hollow cylindrical body in which it is slidably disposed to form on its respective opposite sides two fluid pressure storage reservoirs wherein is stored fluid under pressure for effecting a brake application. This brake apparatus further comprises a novel brake control valve device that is so responsive to a reduction of pressure in a train brake pipe as to first cause simultaneous shifting of both pistons in a brake-applying direction and a transfer of fluid under pressure from one side of the larger piston to the other until a chosen braking force is transmitted through brake rigging to press brake shoes against the wheels of a vehicle.