Abstract: A system for regulating pressure in a hydraulic circuit comprising at least one generator (110) of fluid under pressure, at least one reservoir (120) of fluid under low pressure and at least one pressure receiver (130, 130a, 130b). The system has least one solenoid valve with an electrical winding (18, 18a, 18b) and a moving magnetic core controlling the position of a distributor slide valve (16, 16a, 16b) which slides in a bore (14, 14a, 14b). Bore (14, 14a, 14b) communicates with a first duct (82) connected to the generator (110) of fluid under pressure, a second duct (12) connected to the pressure receiver (130, 130a, 130b) and a third duct (78) connected to the reservoir (120) of the fluid under low pressure. The system operates in response to a first type of control signal. (S1, S, Sa, Sb) derived from a plurality of inputs corresponding to the operation of a vehicle.

Abstract: The invention relates to a vehicle hydraulic brake system with a twin-circuit emergency brake pressure source which can be put into operation by a pedal and with wheel brakes which can be supplied from this emergency brake pressure source through emergency brake main conduits and with a power-assisted brake device which has a power source, and, between the latter and the at least one wheel brake, at least one valve arrangement generates brake pressures and also reduces brake pressure using a pressure medium from the power source. At least one valve arrangement is installed between the emergency brake pressure source and the wheel brakes and, in emergency brake operation, this valve arrangement connects the emergency brake pressure source to the wheel brakes and, in power-assisted brake operation, separates the emergency brake pressure source from the wheel brakes.

Abstract: A work brake system applies a reduced air pressure service brake application as a work brake to hold a heavy duty vehicle in place without actuation of conventional spring brakes during frequent start-and-stop operations of the vehicle, such as in refuse collection. The work brake system includes fail safe features to prevent vehicle roll in the event of loss of air pressure, by providing separate primary and secondary sources of pressurized air, and by automatically diverting to application of spring brakes in the event of primary pressure or signal loss.

Abstract: A braking system which employs redundant hydraulic systems. The system has a first hydraulic system coupled to the brake of a first wheel through a first switching valve, and a second hydraulic system coupled to the brake of a second wheel through a second switching valve. Each switching valve will switch the coupled brake to the other hydraulic system, if the pressure within its system falls below a threshold value. For example, if the first hydraulic system fails, the first switching valve switches the first wheel to the second hydraulic system. If the second hydraulic system fails, the second switching valve switches the second wheel to the first hydraulic system.

Abstract: A pneumatic brake system for use with an additional brake including a by-pass valve in parallel to a shut-off valve. The by-pass valve is opened only during an actuating or controlling of the pneumatic brake which exceeds a control range and opens up the passage through the brake pressure line irrespective of the switching condition of the shut-off valve. The connection of the brake cylinder line section of the brake pressure line with the atmosphere by the shut-off valve is at least choked when the by-pass valve is opened up.

Abstract: An operating brake valve for an electrically and pneumatically actuated braking system in a motor vehicle has a movable thrust piece (2) arranged within a housing (1) and a balance piston (4) actuated via a graduated spring (3), whereby a combined inlet/exhaust valve (7, 9, 10) is arranged downstream of the balanced piston. A position sensor (20) is provided which can be actuated via a push rod (17) connected to the thrust piece (2). A stop valve (29) is located in the connecting line (26) to the reservoir (12) or in the control line (15) coming from the balance chamber, whereby an electrically controlled solenoid valve (40) is provided for actuating the stop valve and, in the nonexcited state, for relieving the valve body of the stop valve (29) opposite to its closing direction.

Abstract: A service brake inspection system engages service brake air lines downstream of a foot operated activation valve thereof to provide continuous engagement of the service brakes during inspection. The system includes a manually controlled air line which supplies air to a source port of an inversion valve. The inversion valve further includes an outlet port which is engaged to air lines supplying the vehicle service brake system via a double check valve in each of the primary and secondary service brake air lines, each being downstream of the foot operated valve. A third control port is connected to an air line disposed between a hand operated valve for exhausting the air lines to the spring parking brakes to set the parking brakes of the vehicle on. When the hand operated exhaust valve is set on, the pathway from the source to the outlet port in the inversion valve is opened to cause the service brakes to be continuously engaged for inspection.

Abstract: A brake control system for a vehicle in which a brake pressure is generated in accordance with a signal from an electronic control unit for applying the brake pressure to vehicle wheels, characterized in that a mechanical brake system is automatically actuated when an unexpected electrical fault has occurred in an electrical brake system.

Abstract: A multi-disk braking device for a vehicle, particularly a train equipped with a braking retarder, includes a first set of metallic braking disks and a second set of carbon braking disks. Under normal operation of the train, the braking retarder is used to slow the train to a predetermined relatively slow speed, and the metallic disks are then actuated to complete the stop. If the braking retarder fails, the carbon disks, not used in normal operation, are actuated to bring the train to a slow speed or to a complete stop.

Abstract: A limited service application of the service brakes of the trailer portion of a tractor trailer combination vehicle is applied and held while the vehicle operator gets out of the cab to make a pre-trip inspection. The service actuation is initiated by releasing the trailer parking brakes while the tractor parking brakes remain applied and then making a momentary service brake actuation by use of the vehicle dual control valve. A control valve assembly responds to the service actuation to hold a service actuation of the trailer brakes until either the tractor parking brakes are released or the trailer parking brakes are applied.

Abstract: A brake control system for an automotive vehicle has an improved hydraulic circuit network which is capable of performing pressure boosting operation for a pressure supplied from a master cylinder, as well as anti-skid brake control operation and traction control operation. The system includes a valve device for selectively establishing and blocking fluid communication between master cylinder and wheel cylinder. The valve device is generally responsive to the fluid pressure supplied from the master cylinder to enter into pressure boosting mode in response to increase in the fluid pressure from the master cylinder across a predetermined value. An electronically operable boost control device cooperates with the valve device for varying pressure boosting magnitude depending upon vehicle driving condition.

Abstract: A shift to control for retaining the braking force from the control for elevating the braking force is implemented when deceleration of the wheel exceeds a first predetermined threshold value when the wheels are braked. The first predetermined threshold value is so set as to become smaller as an assumed road surface friction coefficient .mu. is smaller. The first threshold value is further altered to a larger value by altering the assumed road surface friction coefficient .mu. to a higher one when the period of time required from the start of the control for elevating the braking force to the start of the following control for retaining the braking force is equal to or shorter than a predetermined period of time.

Abstract: A multi-axle vehicle equipped with an antilock braking system which provides regulated braking operations to prevent locking of the wheels when the vehicle is braked and spinning of the wheels when the vehicle is started up, comprises a front axle, first and second rear axles, the first rear axle being a drive axle and the second rear axle being a liftable following axle, wheels mounted on each of the axles, rotational speed sensors producing signals indicative of the rotational speeds of the wheels associated with each of the wheels mounted on the front axle, on the drive axle, and on the following axle, brake cylinders associated with each of the wheels, a circuit supplying a pressure medium to the brake cylinders so that a braking pressure is applied to the wheels, and at least one electronic control unit which controls the braking pressure applied to each of the wheels.

Abstract: In a noise reduction circuit with a main signal path and an auxiliary signal path having a high-pass filter characteristic, the noise reduction circuit comprises: a voltage-to-current converting circuit having a differential input and output and connecting the auxiliary signal path to the main signal path, PN junction transistors connected to the differential output of the voltage-to-current converting circuit, a paired common-emitter transistor arrangement having one base electrode connected to the PN junction transistors, a capacitance connected to a first differential input of the voltage-to-current converting circuit, a feedback resistor connecting a collector of a first common-emitter transistor pair of the paired common-emitter transistor arrangement to the first differential input of the voltage-to-current converting circuit, a voltage buffer having the collector of the first common-emitter transistor pair of the paired common-emitter transistor arrangement and a voltage dividing resistance connected t

Abstract: An anti-locking brake system for automotive vehicles, comprising a tandem master cylinder (1), a device (3, 4) for modulating the pressure supplied to the wheel brakes, an anti-locking control device (2) including a pressure reducing valve (10) located in the rear-axle brake circuit (7). The pressure reducing valve can be activated only in the event of failure of the anti-locking device. To attain a particularly simple and compact design of the re-switchable brakes force distributor (10, 110), an electromagnetic drive (21, 25, 121, 125) is provided and includes an actuating element (20, 120) through which pressure is directly applicable to the valve closing member (16, 116) of the pressure reducing valve (14, 15, 16, 114, 115, 116). To ensure the pressure reducing function even in the event of a failure of the anti-locking device during a brake actuation, an additional arrangement (134, 135, 136) for the volume expansion is provided.

Abstract: A brake system (20) comprising: a master cylinder (26) and a pump (12) for selectively pressurizing an associated brake cylinder or cylinders; a motor (14) for powering the pump; a control circuit (16,90) for modulating motor speed in response to a signal indicative of desired braking effort and actual braking effort; and a control valve (30) responsive to master cylinder pressure for controlling pump flow and for permitting the decay of pressure in the brake cylinders.

Abstract: A known brake circuit comprises a mechanical brake-pressure control device and an electrical brake-pressure control device. The mechanical brake-pressure control device is furnished for assuring an emergency operation in case of a fault of the normally predominance-taking electrical brake-pressure control device. The known brake circuit can be controlled only then in a load-dependent way, when both the mechanical as well as the electrical brake-pressure control unit comprise a load-dependent automatic brake-pressure controller. According to the invention, a restraining device (103 3, 5) is furnished in the mechanical brake-prerssure control device (103 3, 5). The restraining device (3) allows for passage of the brake pressure, set in the mechanical brake-pressure control device (103 3, 5), only in case of a fault in the electrical brake-pressure control device (106 6, 9, 12, 13).

Abstract: The brake valve control system for an aircraft wheel bracking system includes primary and backup brake valve control subsystems and isolates and switches between subsystems. Certain portions of the entire braking system are shared, and those portions which are not shared are isolated but interconnected for switching from a primary brake control mode to a backup subsystem upon failure of the primary subsystem. A unique metering spool valve, and the linking of metering spool valves and servocontrol valves with either a tandem selector valve or interlinked primary and secondary selector valves allows for significant reduction in weight and complexity for the backup or override system.

Abstract: A trailer braking system for a towing vehicle has a trailer braking valve (26) is fed with a pressurized air supply which is modulated by the opening of the valve, as controlled by a first control pressure regulated by a trailer braking controller (24) in accordance with braking demand signals, to produce a trailer braking pressure. In order that a trailer braking pressure may be generated even if the above trailer braking valve control fails, the valve is supplied with a second control pressure independently of the first, and which is also capable of operating the trailer braking valve (26). In a preferred embodiment, the second control pressure is supplied from a braking line of the towing vehicle, such that the "back up" control pressure is a function of the towing vehicle braking.

Abstract: The combination isolation and check valve includes a valve member (80, 180) which has a reduced diameter section (82, 182) and an enlarged diameter section (84, 184) disposed in respective bore sections (70, 74) separated by an intermediate diameter bore section (72). The valve member can be displaced by increased fluid pressure to sealingly engage a seal (95) that isolates a master cylinder (12) from an adaptive braking system (10, 120). A flapper valve mechansm (110) that places an rifice (114) at a valve member end opening (96A) communicating with a longitudinal opening (96) and a transverse opening (93). The orifice (114) reduces pressure transmitted from a pump (45) to the bore (22) containing the valve member (80) without restricting fluid flow between the master cylinder (12) and an associated wheel brake (50). The valve mechanism (210) may be disposed in a passage (41) that communicates with the valve member (180).

Abstract: A vehicle hydraulic braking system for applying the wheel brakes of an automotive vehicle comprising: a reservoir for holding a hydraulic brake fluid; a pump fluidly connected with the reservoir for pressurizing the fluid; at least one first valve fluidly connected with the pressurized fluid from the pump and the first valve being connected with a modulation sump, the first valve delivering a modulated brake pressure to at least one wheel brake at a ratio of the master cylinder pressure to the wheel pressure so long as the fluid pressure from the pump is above a predetermined value; and a second valve fluidly connected with the wheel brake, the master cylinder, the modulated brake pressure, and with the pump and, whereby the second valve isolates the master cylinder from the wheel brake when the pump pressure is above a predetermined value delivering modulated pressure to the wheel brake and when the pump pressure is below a predetermined value the second valve connects the master cylinder with the wheel brak

Abstract: A braking apparatus for a vehicle has a booster for receiving, as a pilot pressure, a pressure of a master cylinder and for regulating a pressure from an auxiliary pressure source to a level predetermined times the pilot pressure. The booster is provided with an initial pressure raising mechanism for causing the booster to output a predetermined initial pressure in response to an initial actuation of a brake pedal.

Abstract: An electrically-controlled motor vehicle brake system, which responds to fluid pressure supplied from a common source. The system includes an electronic control system to process information and issue brake commands. A brake cylinder, to apply and release brake pressure on each respective wheel brake, receives pressure from at least one solenoid valve, connected to receive pressure from the source. The pressure is communicated to the brake cylinder of each respective wheel brake upon receipt of a control signal from the control system. A brake power selector includes both a pedal-operated brake valve, connected on an input side to receive pressure from the source, and connected on an output side to a ventilation portion of the solenoid valve for modulating the brake pressure, and an electrical frequency selector is connected to provide an input signal to the electronic control system upon actuation by an operator of such vehicle during a brake application.

Abstract: The device comprises a tandem master cylinder, a booster high pressure fluid distributor, 2, a valve mechanism 4 to interconnect the master cylinder and the distributor selectively to a braking circuit. The high pressure circuit is connected to the pipeline 46 which controls the plungers 52, 56 acting on the ball valves 50, 51 respectively. In the event of failure of the high pressure circuit,the valves 50, 51 connect the pipeline 26 directly supplied by the master cylinder and the pipeline 5 which supplies a brake motor 8 for a wheel. The device may be utilized in an anti-skid circuit.

Abstract: An automatic drive slip regulating unit for motor vehicles or the like which communicates via a connecting line with at least one brake line between a master brake cylinder and an anti-skid system with wheel brakes connected downstream. The connecting line is intended to discharge into a cylindrical chamber of an additional master cylinder, and the cylindrical chamber is intended to be variable by a plunger that is subject to the pressure of a spring-supported spring reservoir plunger. To return this spring reservoir plunger to its terminal position, for instance in the event of leakage or upon termination of the drive slip regulation, the spring reservoir plunger is to be subjectable on its other side to a pressure medium which derives from a separate low-pressure hydraulic circuit.

Abstract: A manually/electrically operated brake system for applying a brake to a wheel of a vehicle, including a master cylinder operated by a brake operating member, to generate a manually controlled braking pressure according to an operation of the brake operating member, a wheel brake cylinder for applying a brake to the wheel, a primary fluid passage for connecting the master cylinder to the wheel brake cylinder, an electrically controlled pressure generating device for generating an electrically controlled braking pressure to produce a required braking effect determined based on at least one of an operating force and an operating stroke of the brake operating member, and a switching device provided in the primary fluid passage, for applying the electrically controlled braking pressure to the wheel brake cylinder while disconnecting the master cylinder from the wheel brake cylinder when the electrically controlled pressure generating device is normally functioning, and for applying the manually controlled braking

Abstract: An anti-jackknifing valve is designed for use with tractor trailers and is operably inserted in the hydraulic fluid brake line of such vehicles. The valve prevents jackknifing of a trailer during brake applications by initially actuating the brakes on the trailer. The valve arrangement directs hydraulic brake fluid to the trailer brakes first, and a continuing movement of the valve piston then permits hydraulic brake fluid to be delivered to the tractor brakes to thus substantially eliminate the risk of jackknifing.

Abstract: A brake source select system for selecting one of a plurality of sources of pressurized hydraulic fluid for use in actuating a brake system. The brake source select system (10) includes a primary, secondary and reserve source (20, 22 and 24) of pressurized hydraulic fluid connected in fluid communication respectively to a primary selector valve (32), a secondary selector valve (96) and a reserve selector valve (102). Pressurized hydraulic fluid from the primary source (20) is applied to deselect ports (94 and 100) on the secondary and reserve selector valves, causing those valves to block fluid flow from their associated sources to the brake system, so long as the primary source is operative.

Abstract: An anti-lock braking system includes a master cylinder for supplying pressurized fluid to the vehicle brakes and a pump which operates during anti-lock control to supply fluid during brake pressure build cycles. A braking circuit includes decay valves and build valves to control communication of fluid pressure to the vehicle brakes in response to commands generated by an electronic control unit. A braking source control valve responds to signals generated by the electronic control unit to switch communication of fluid pressure to the braking circuit between the master cylinder and the pump.

Abstract: A parking brake control device has a differential area shuttle valve which has an outlet connected to a brake actuator and a larger area of a poppet directed to an inlet connected to a control valve for applying a parking brake pressure and a smaller area of the poppet facing a second inlet connected to a service brake pressure such that in the event of simultaneous application of parking brake and service brake pressures the shuttle valve will be moved to close off the inlet to the service brake pressure while introducing park brake pressure to the brake cylinder.

Abstract: A multi-circuit pressure medium brake system in which a pressure control valve is used which can be triggered in a multi-circuit manner. One of the controls is effected electrically and generally advances ahead of a pressure-medium control, so that when the system is functioning properly, the pressure-medium control remains without effect. Various modifications for the pressure control valve have been set forth and a plurality of combinations of switching members for meeting various pressure regulating conditions have been set forth. The multi-circuit pressure medium brake system is preferably applicable to motor vehicles.

Abstract: A braking apparatus for vehicles has a switching device which controls the admission of pressure fluid to the braking cylinder of a service brake and is operated by a reaction force acting upon a coupling or bearing support between the switching device and a lever operatively connected to a parking or locking brake. When this reaction force exceeds a predetermined limit upon operation of the parking brake, the switching device is actuated to release the service brake. The service brake is released at that time when the parking brake already applies a braking force and the short period of time between the parking brake being locked and prior to release of the service brake is so short that the brake linkage of the service brake is not subjected to any damaging effects.

Abstract: A vehicle braking system is provided having alternate, automatically selected actuating fluid circuits, either hydraulic or air circuits, interconnected between a master brake cylinder actuated by a vehicle operator and a brake actuating cylinder that operates the brake shoes at a wheel of the vehicle. A first actuating fluid circuit is normally connected in communicating relationship between the master cylinder and actuating cylinders by fluid-pressure responsive valves. Failure in buildup of fluid pressure in the first circuit when the master cylinder is actuated, such as would be due to a break or leak in the primary actuating fluid line, results in automatic operation of the valves to interconnect a second circuit in bypass relationship to the first circuit. The pressure responsive valves are not operational unless the brake master cylinder is being actuated.

Abstract: This invention relates to a railway locomotive brake control apparatus operably either manually by an engineer or automatically in response to a change in a train control signal indication to a more restrictive indication to effect a brake application on the locomotive and a train of cars hauled thereby unless the automatic train control brake application is suppressed by the engineer manually effecting a full service brake application. When the engineer thus manually effects a full service brake application upon the occurrence of the more restrictive signal indication, the fluid under pressure released from the train brake pipe to cause this brake application is used to temporarily suppress the automatic train control brake application so long as fluid under pressure is being released from the train brake pipe to atmosphere via a restriction.

Abstract: A control system for a spring-applied service brake which can also be used as a parking brake. Pressure from the vehicle hydraulic system is normally used to release the brakes. In the event of a loss of the primary pressure from the hydraulic system, the control system switches automatically to use of secondary pressure from the vehicle compressed air system to release the brakes, while maintaining the ability of the operator to apply the brakes by normal operation of the service and parking brake controls.