Abstract: Apparatus for indicating the condition of hand brakes on railway cars and for applying and releasing railway car parking or hand brakes automatically in response to predetermined conditions including movement of a train, wayside conditioning apparatus, wayside operating mechanism, a signal controlled by an operator and performance of predetermined railway operating procedures, such as completion of an air brake test procedure. The apparatus may respond to mechanical, electrical and electronic signals and may operate on pneumatic or electric power provided from the service air brake system of a train or from a source of power outside of such air brake system.

Abstract: In a vehicle train comprising a motor vehicle and a trailer, a process for monitoring a trailer brake for overload comprises producing an energy call-up signal during a braking action, supplying energy to a motor vehicle brake in the motor vehicle, the amount of energy being supplied to the motor vehicle being determined, at least in part, by the value of the energy call-up signal, producing a trailer energy signal, the value of the trailer energy signal being determined, at least in part, by the value of the energy call-up signal, and supplying trailer energy to a trailer brake in the trailer, the amount of trailer energy supplied to the trailer brake being determined, at least in part, by the value of the trailer energy signal. The process further comprises monitoring the coupling force appearing at a coupling between the motor vehicle and the trailer, and adjusting the coupling force based on the trailer energy signal.

Abstract: A controller of the invention is used for tractor trailer braking devices having a service brake, an exhaust brake and a retarder brake for a tractor, and a retarder brake for a trailer. The controller includes a main operating switch situated at a driver seat for controlling the exhaust brake and the tractor and trailer retarder brakes, a first interlocking switch for interlocking between the service brake and the tractor and trailer retarder brakes, a second interlocking switch for locking the tractor retarder brake, a first device to detect a condition of an accelerator pedal, a second device to detect a condition of a clutch, a third device to detect a condition of a brake pedal, and a fourth device to detect a condition of a trailer brake. The controller can effectively utilize the exhaust brake, and the tractor and trailer retarder brakes according to the driver's intention.

Abstract: A braking system is improved by addition of a spring brake pressure protection valve, to prohibit pressurization of the spring brakes prior to the build up of sufficient pressure to insure complete release of the spring brakes. This prevents the significant problems associated with known systems that permit operation of a tractor trailer with partially released spring brakes, which will cause unnecessary wear and reduced fuel economy. The spring brake pressure protection valve is located between the reservoir and the spring brakes, most preferably between the spring brake quick release valve and the spring brakes, or alternately, between the reservoir and the spring brake quick release valve.

Abstract: The brake energy balancing system balances brake torque of braking wheels of a vehicle having a plurality of cars carried by trucks, for applying and controlling the brakes of each group of braking wheels of the trucks of the vehicle. Brake torque is measured, a command brake torque signal is generated that is limited by a reference torque signal, and the command brake torque signal is compared with the measured brake torque to generate brake torque difference signals. An energy balancing brake application control signal is provided to the brakes in response to the brake torque difference signals.

Abstract: An apparatus for simultaneously applying brakes of a towed vehicle having a self contained braking system when brakes of a towing vehicle are applied is described. This apparatus includes a vacuum pump linked with a vacuum booster in the braking system of the towed vehicle thereby providing vacuum pressure to the vacuum booster. A servomotor linked with a brake pedal in the braking system of the towed vehicle. Upon activation, the servomotor provides force to move the brake pedal thereby applying the brakes in the towed vehicle. A pedal position sensor is linked with the brake pedal in the towing vehicle, whereby the brake pedal position of the towing vehicle is sensed. An encoder is linked with the pedal position sensor. The encoder receives data from the pedal position sensor regarding the brake pedal position of the towing vehicle and encodes such data. A decoder is linked with the encoder and the servomotor.

Abstract: A braking system including a brakepipe control valve which controls pressure on a brakepipe in response to braking pressure signal from an electropneumatic converter. An electropneumatic cutoff valve connects the control valve to the brake pipe. A controller controls the converter and cutoff valve. A parking brake system and retarder control system are also included and are controlled by the controller.

Abstract: A system and method for determining vehicle mass relative to a previous mass of the same vehicle utilizes a closed-loop control system to bring the vehicle to a controlled deceleration upon initiation of the procedure. The relative mass of the vehicle is determined by sensing the applied braking pressures at each of the vehicle axles and processing that information to generate the total braking force being applied to the wheels of the vehicle. Since a greater mass requires a greater braking force to achieve the same deceleration, the necessary braking force is indicative of the relative vehicle mass. An appropriate braking mode such as work balance, proportioning, or ABS, can then be determined based on the relative vehicle mass to better control subsequent braking maneuvers.

Abstract: In a vehicle train comprising a motor vehicle and a trailer, a process for monitoring a motor vehicle trailer brake for overload comprises producing an energy call-up signal during a braking action, supplying energy to the motor vehicle brake in the motor vehicle, the amount of energy being supplied to the motor vehicle being determined, at least in part, by the value of the energy call-up signal, producing a trailer energy signal, the value of the trailer energy signal being determined, at least in part, by the value of the energy call-up signal, and supplying trailer energy to a trailer brake in the trailer, the amount of trailer energy supplied to the trailer brake being determined, at least in part, by the value of the trailer energy signal. The process further comprises monitoring the coupling force appearing at a coupling between the motor vehicle and the trailer, and adjusting the coupling force based on the trailer energy signal.

Abstract: A full-function brake valve for a tandem trailer is contained within a single housing and provides a boost to the control air signal arriving at the full-function valve so that the control air signal can be delivered to a second trailer full-function valve without degradation of the control air signal. The signal boost function is provided by an aperture in the piston of the relay valve that connects the control air inlet to the supply air, to cause the supply air pressure to boost the control air signal.

Abstract: A device for applying the brake of a towed vehicle when towed by a towing vehicle equipped with an air brake system having a power brake operator operative to supply operating air under pressure to apply a brake on the towing vehicle and also having a reservoir of operating air under pressure. The device is connected to the brake pedal of the towed vehicle. It comprises a first piston-cylinder assembly with a spring for urging the piston therein to an advanced position, and a second piston-cylinder assembly having a spring urging the piston therein to a retracted position. The brake on the towed vehicle is applied only when one of the pistons is advanced. An air line supplies air from the reservoir to the first piston-cylinder assembly to urge the piston to a retracted position against the action of the spring.

Abstract: A fluid control system for use with vehicles, in particular, trailers, includes a branch conduit (19, 25, 42, 80, 96) which is to be connected to a pressure supply line (20) and a control line (22) to enable priming of the control line (20) so that signals generated upon application of the vehicle brake pedal are more quickly transmitted to the trailer brakes. This overcomes problems associated with delay in application of the trailer brakes. An electrically operated solenoid valve (11) controls fluid flow through the branch conduit so that upon application of the vehicle brake pedal the solenoid valve is operated to open the branch conduit to allow pressurized fluid to flow from the supply line (20) to the control line (22) for a predetermined time period to prime the control line (22).

Abstract: The hydraulic disc brake actuator for a trailer includes a first connector for securing the actuator to a towed vehicle; a second connector for securing the actuator to a towing vehicle; and a force multiplying parallel linkage apparatus connected between the first and second connectors for actuating a brake master cylinder. The master cylinder has a body portion and a plunger portion, the body portion being connected to one of the first or second connectors and the plunger portion being connected to the force multiplying apparatus such that the magnitude of force applied to the master cylinder is greater than the magnitude of force tending to move the first connector relative to the second connector. The parallel linkage supports and lifts the tongue weight of the trailer to dissipate energy, and to prevent binding between the connectors when they shift from a towing position to a braking position.

Abstract: A full function valve incorporating a proportioning valve module that initially directs supply air pressure during initial system charging to the spring brake chambers to prepare the spring brakes for prompt release when there is sufficient system supply air pressure to operate the service brakes. The proportioning valve module then opens to increase supply air pressure to the reservoir, while charging of the spring brake chambers continues, until the service brakes become operable and the spring brakes disengage.

Abstract: A unitary full-function valve is used to control the operation of a service brake system and a spring brake system. The valve includes a valve body that has multiple ports, including separate ports for providing fluid communication to a spring brake chamber, a service brake chamber, a fluid reservoir and an exhaust port. The valve body also has ports for receiving pressurized supply fluid and control fluid. The supply fluid inhibits the activation of the spring brakes so that the spring brakes are activated when no supply fluid is present. The control fluid is used to activate the service brakes on demand. A biased one-way pressure protection valve is disposed in the valve body to isolate fluid in the service brake system from fluid in the spring brake system when the pressure in the service brake system falls below a variable pressure level.

Abstract: An integrated throttle position validation sensor includes electrically independent throttle position and position validation components responsive to a single mechanical input applied to a protective sensor housing. By suitable mounting to the throttle control device, the mechanical input corresponds to accelerator pedal position. Within the sensor housing a potentiometer moves with the mechanical input whereby a variable voltage throttle position signal is generated. Also, within the housing a separate validation switch responsive to the mechanical input provides an independent representation of throttle control device position in the form of, for example, a bi-state validation signal. The sensor integrates previous separate throttle control position and position validation functions into a single environmentally secure housing which requires no calibration. The integrated sensor is more reliable and less costly than previously available separate throttle control and idle validation functions.

Abstract: A relay valve device for a relayed type brake system in which the compressed air of the auxiliary reservoir is connected to an equalizing reservoir instead of directly to the brake cylinder, as in a conventional system. Since the equalizing reservoir volume is fixed, as compared to the brake cylinder volume which varies with piston displacement, the equalizing reservoir volume must be greater than the final brake cylinder volume in order to obtain a full equalization pressure that matches the full service application pressure in a conventional brake system. The relay valve device employs a control piston that is subject opposingly to the equalizing reservoir pressure and the effective brake cylinder pressure delivered by the relay valve device.

Abstract: A braking system for a vehicle having primary and secondary braking circuits includes a secondary braking circuit having a secondary source of braking pressure connectable to a braking actuator and including a three-port, two-position, inlet solenoid valve having two inlet ports and one outlet port. One of the inlet ports is connected to an outlet of an inlet solenoid valve of the primary braking circuit and to the inlet of an exhaust solenoid valve of the primary braking circuit. The other inlet is connected to a secondary source of braking pressure. The outlet port is connected to the braking actuator. The inlet solenoid valve is movable by an output signal from an electronic control unit.

Abstract: A full function brake valve for a semi-trailer is contained within a single housing and provides ports for receiving supply air and control air, and for delivering and receiving air from reservoirs, service brakes and spring brakes, and delivering air to an exhaust. The internal valves include a reservoir check valve and a relay valve to respectively pressurize a reservoir and to deliver supply air to service brakes. A secondary reservoir is supplied via a secondary reservoir check valve and a secondary reservoir outlet in the full function valve, or in a secondary relay valve, and is controlled by a secondary relay valve module to provide a redundant braking system for additional safety.

Abstract: A full function brake valve for a semi-trailer is contained within a single housing and provides ports for receiving supply air and control air, and for delivering and receiving air from reservoirs, service brakes and spring brakes, and delivering air to an exhaust. The internal valves include a pressure protection valve which communicates with a first check valve and a quick release valve to pressurize spring brake chambers, and a reservoir check valve and a relay valve to respectively pressurize a reservoir and to deliver supply air to service brakes. An orifice preferably provided in a second check valve permits partial air flow to the spring brakes to release the spring brakes for towing the vehicle.

Abstract: A braking system for a vehicle such as a trailer having electric brakes which utilizes a carbon-pile voltage regulator. A piston of the regulator is responsive to hydraulic pressures occurring in the tow vehicle brake system to bias the disks to increase current flow. An electromagnet is utilized to preload the carbon disks with a gain control provided in circuit with the electromagnet to vary preloading. Mechanical means are provided in the regulator to limit outward displacement of the piston component of the regulator and, in a modified form of the regulator, a core of the electromagnet. Hydraulic fluid acting on the regulator is isolated from the fluid of the hydraulic brake system by a diaphram unit.

Abstract: A large articulated vehicle, such as a tractor semi-trailer truck often has a number of braking locations each having a number of brake sites. To properly balance the work performed at the various brake sites in decelerating the vehicle, it is necessary to determine the relative brake factors of each site. The brake factors characterize the braking performance for a particular delivered braking pressure. A system and method for determining the relative brake factors for such a vehicle is provided. The vehicle is decelerated at a known rate while delivered braking pressure is measured and recorded for each braking location. A system of simultaneous equations is then solved to determine the relative brake factors. Once the brake factors have been determined during a sequence of controlled braking events, subsequent braking may be modified to achieve a work-balanced braking mode.

Abstract: A trailer brake system includes a disc brake assembly for each wheel including apparatus to provide release of the brake pads from engagement with the rotor upon backing. In the preferred braking system, one master brake assembly is provided for braking one wheel and a slave brake assembly for braking a second wheel of the trailer; a self-contained hydraulic actuator being provided for moving the pads into and out of engagement with the rotor. Each brake assembly includes a stationary bracket for attachment to the axle and a caliper unit with the brake pads mounted by a single pivot pin on the bracket. A relief valve is engaged by the pivoting caliper unit to provide the release of the brake pads. The housing of the caliper unit is in two sections and mounted adjacent the top of the rotor.

Abstract: System for selectively applying the brakes of a towed vehicle by controls in the towing vehicle; the system including a portable air compressor and a pneumatic cylinder that can be rapidly installed by attaching to a support structure on the floor of the driver's cockpit in the towed vehicle; the piston of the cylinder being attached to the brake pedal; and a three-way solenoid valve to permit or not to permit the admission of compressed air to the cylinder.

Abstract: Optimum braking effectiveness and control of a vehicle are obtained by continually evaluating estimated values of friction coefficients as they increase with decreasing vehicle velocity during vehicle braking and by increasing brake pressure accordingly to maintain the pressure just under a value at which vehicle control is compromised. This is enhanced by determining a maximum pressure that can be applied to each brake sight while maintaining the rate of change of the articulation angle between a tractor and trailer of the vehicle equal to zero. A further enhancement is obtained by estimating critical vehicle velocity as a function of steering angle, thus enabling braking effectiveness and control to be a function of maneuvering conditions.

Abstract: A method is provided to determine an optimized value of the brake pressure ratio between a tractor and a trailer or semitrailer. In particular, an increased value of the brake pressure of the trailer or semitrailer in relation to the brake pressure resulting from the position of the brake pedal is supplied for a particular duration at the beginning of a braking operation. The increase of the brake pressure of the trailer or semitrailer takes place as a function of the brake pressure, p.sub.Anh, resulting from the position of the brake pedal. In braking operations when a tractor is travelling without a trailer or semitrailer, an allocation of the achieved deceleration, z.sub.ist, to the brake pressure p.sub.Zug of the tractor is stored as a function of the load state of the tractor.

Abstract: A full function skid control valve assembly for use in an air brake system which provides for brake control utilizing a compact single assembly. The system provides for the maintenance of certain minimum operating pressures so that, when the air pressure within the vehicle brake system falls below predetermined levels, the valve assembly automatically partially or entirely exhausts the air pressure sometimes causing the spring parking brakes to engage. Once the air pressure within the brake system returns to predetermined levels, the valve assembly will allow a reservoir to be charged and the spring brakes to be deactuated. During operation, the assembly provides control of the service brakes while preventing undesired skid conditions.

Abstract: A process and apparatus for the braking with optimized stability of a vehicle train is disclosed. The vehicle train comprises at least two individual vehicles, one of the individual vehicles supporting the individual vehicle. The process comprises supplying energy to the brakes of the vehicles, thereby actuating the brakes and producing an actual force between the vehicles, and measuring the actual-value horizontal and vertical components (F.sub.hact, F.sub.vact) of the actual force (F.sub.act) acting between the supporting and supported vehicle. A desired-value horizontal force component (F.sub.hdes) of the force is determined by multiplying the actual-value vertical component (F.sub.vact) by the ratio of the actual-value train deceleration (b) to the earth's acceleration (g). The desired-value horizontal force component (F.sub.hdes) is then compared with the actual-value force horizontal component (F.sub.hact). The energy supplied to the brakes is adjusted so that F.sub.

Abstract: An all-weather braking aid for a vehicle having brakes actuated by air pressure. The all-weather braking aid includes at least one motion detector responsive to inertia of the vehicle. A sensor is operatively engaged with the motion detector and a switch is activated by the sensor. The pressurized air is directed to a valve, the valve is normally in an open position to allow flow of the air pressure and movable to a closed position to interrupt the air pressure. The timer is engaged with the switch in order to close the valve for one selected duration and then open the valve for another selected duration, thereby providing controlled intermittent braking.

Abstract: The brake energy balancing system balances brake torque of braking wheels of a vehicle having a plurality of cars carried by trucks, for applying and controlling the brakes of each group of braking wheels of the trucks of the vehicle. Brake torque is measured, a command brake torque signal is generated that is limited by a reference torque signal, and the command brake torque signal is compared with the measured brake torque to generate brake torque difference signals. An energy balancing brake application control signal is provided to the brakes in response to the brake torque difference signals.

Abstract: The electrohydraulic or electropneumatic braking-control device for axles of trailers having mechanical brakes includes a hydraulic or pneumatic circuit mounted on the trailer, made up principally of a pressure accumulator, the internal pressure of which is automatically adjusted above a minimum value, as well as of a control gate, the opening of which is proportional to a control current function of the pressure exerted on the brake pedal of the tractor vehicle and of an adjustment carried out as a function of the load of the trailer. In case of attachment parting or of unhitching of the trailer, the disconnection of the connection plug actuates a safety valve that automatically controls the energetic braking of the trailer. The safety valve includes a manual control. It is possible to unbrake, then to rebrake the trailer in order to maneuver it. The trailer braking device may be mounted from the outset or subsequently, requiring only few transformations of the tractor vehicle.

Abstract: A trailer stability brake control method is disclosed for an articulated vehicle 11 which involves determining values indicative of tractor turning radius of curvature (TRC), articulation angle (AA) and time derivatives thereof, a value for wheel speed variance (WSV) is determined, and then a stability indicator (SI) is determined for each of TRC and AA, and the time derivatives thereof. The later step is performed by signal processing means (63) including filter means having a cutoff frequency (.OMEGA..sub.c) with the cutoff frequency decreasing as the wheel speed variance increases, and vice versa. The trailer brake control means (125) is de-actuated whenever the stability indicator (SI) relating to the articulation angle (AA) becomes less than the wheel speed variance.

Abstract: An anti-theft device is coupled in series with a supply line and a service line of a trailer. When activated, the anti-theft device prevents theft of the trailer by decoupling the supply and service lines of the trailer from the reservoir and brake cylinders of the trailer, and by coupling the supply and service lines to the atmosphere, thereby preventing a prospective thief from releasing the trailer's brakes by restoring air to the supply and service lines. When the anti-theft device is deactivated, the supply and service lines are re-coupled to the reservoir and brake cylinders to allow the driver to release the trailer brakes.

Abstract: A fluid pressure system and stoplight control circuit for a towed vehicle which is either an intermediate unit or the last unit of a vehicle train includes an inlet supply line for receiving fluid pressure from a preceding unit and an outlet supply line which is connected to a corresponding coupling of a succeeding unit when the vehicle is an intermediate unit and which is connected to a coupling hanger when the unit is the last unit of a vehicle train. A pressure responsive stop light switch is connected into the coupling hanger. Accordingly, when the outlet supply line is connected to the coupling hanger, the contacts of the stop light switch are closed, thus permitting power to the stop lights when a brake application is effected. However, when the outlet supply line is connected to a succeeding vehicle, the coupling hanger is vented, so that the contacts of the pressure responsive switch are open, thus interrupting power to the stop lights and conserving power on the vehicle.

Abstract: A hydraulic braking system for a towed vehicle provides actuation of the hydraulic pump motor of the towed vehicle responsive to an electrical switch which is closed upon application of the brake pedal of the towing vehicle. However, even after actuation of the hydraulic pump, the towed vehicle brakes are only able to be applied in response to sensed relative movement of the towing and towed vehicle toward each other. A break-away switch sets the trailer brakes in the event of accidental separation of the towed vehicle from the towing vehicle. The control valve may be used in other situations to control a hydraulic pump and associated hydraulic braking system.

Abstract: Brakes mounted on the wheels of slidably adjustable axles used with truck trailers are connected by a pair of flexible coiled tubes to service and emergency air lines. The flexible coiled tubes are mounted one within the other and have identical end fittings which connect directly to service and emergency air lines and directly to airbrake lines. No intermediate fittings are utilized. The end fittings of each coiled tube are also mounted in fixed relation to a transverse support bracket mounted on the trailer body and to a bracket mounted on a rear axle support. Each end fitting has first, second, and third threaded portions, with the first threaded portion coupled to the end of one of the coiled tubes, the second threaded portion being received through a hole in a bracket, and the third threaded portion being coupled with either an air pressure supply line or an airbrake line.

Abstract: A fluid pressure braking system for a tractor-trailer combination vehicle includes a proportioning relay valve which controls communication to the rear wheel brakes of the tractor. When the tractor pulls a trailer, the proportioning control within the relay valve is disabled, but when the vehicle is operated in the "bobtail" mode without pulling a trailer a proportioned brake application is effected in which the braking pressure communicated to the rear brake actuator is a predetermined percentage of that in the front wheel braking circuit. The proportioning mechanism is also disabled when the front axle braking circuit malfunctions, so that upon loss of pressure of the front axle system, the driver effects a non-proportioned rear brake application.

Abstract: An air distribution apparatus (10) is configured for retrofit between the service portion (24) and pipe bracket portion (26) of a conventional AB valve (16) of a railroad car braking system (12) for allowing operation with an electronic controller (14). The apparatus contains openings and passageways compatible with the connections between the service and pipe bracket portions of the AB valve while providing additional conduits to mate with the electronic control device.

Abstract: A brake pressure regulation method and system for a trailer vehicle, which is connected to a tractor vehicle having an electronically controlled pressure-medium brake renders sensing of the forces between the tractor and the trailer vehicle and, to this extent, also a corresponding force-recording apparatus superfluous. The method can be used advantageously in tractor vehicles equipped with an ABS. The method is based on transmission of wheel speed signals from the trailer vehicle to the tractor vehicle and brings about an adjustment of the brake pressure relation between the tractor and the trailer vehicle to the same average speed of the wheels of non-driven axles of the vehicle by correcting the brake pressure for the trailer vehicle adaptively to give braking work which can be distributed in optimum fashion to the tractor vehicle and the trailer vehicle.

Abstract: An electronic controller for outputting pulses of current to actuate towed vehicle brakes includes a trigger point inertial sensor for varying the gain thereof. The trigger point inertial sensor includes a switch connected to the controller for switching the gain between two levels. In the preferred embodiment, the inertial sensor and switch comprise a mercury switch supported on a platform which is rotatable to adjust the switching threshold of the inertial sensor, and to adjust for the mounting position of the brake control.

Abstract: A valve assembly for use with spring-set air-release vehicle parking brakes comprises a particular arrangement of conventional components providing desired spring brake operational characteristics heretofore requiring costly, complex specially-designed units. The valve assembly typically employs a plurality of interconnected check valves in combination with pressure protection and quick release valves to provide the desired characteristics. These include a system whereby at startup pressurized air from the tractor fills the trailer reservoir tanks and the spring brake chambers simultaneously. The valve assembly also assures that if during tractor-trailer operation the supply air from the tractor is severed or otherwise lost, service brake air in the trailer reservoir tanks is retained at a sufficient pressure to provide adequate service brake operation.

Abstract: A trailer brake system includes a disc brake assembly for each wheel including apparatus to provide release of the brake pads from engagement with the rotor upon backing. In the preferred braking system, one master brake assembly is provided for braking one wheel and a slave brake assembly for braking a second wheel of the trailer; a self-contained hydraulic cylinder being provided for moving the pads into and out of engagement with the rotor. Each brake assembly includes a stationary bracket for attachment to the axle and a caliper unit with the brake pads mounted by a single pivot pin on the bracket. A relief valve is engaged by the pivoting caliper unit to provide the release of the brake pads. The housing of the caliper unit is in two sections and mounted adjacent the top of the rotor.

Abstract: Brake wear between braking sites of a vehicle is equalized by measuring work performed at the braking sites, comparing the amount of work performed at each braking site with an average calculated for all braking sites, and increasing braking demand at any braking site performing less than the average amount of work.

Abstract: A trailer braking control system which is adapted to modify trailer braking from a towing vehicle by regulating the coupling head service braking pressure signal generated on the towing vehicle in response to driver's demand pressure and measured values of longitudinal force exerted on the trailer coupling just before and during braking. At least two adaptive variables are developed on the towing vehicle, and on selected qualifying stops of the towing vehicle/trailer combination, one of these adaptive variables is chosen to be corrected at the end of that stop using average trailer thrust error signals for use in regulating trailer braking on subsequent stops.

Abstract: A traction controlling apparatus employable in a multi-axle vehicle wherein anti-lock braking and traction controlling can be achieved with a small number of channels. The traction controlling apparatus is constructed such that air pressure control type cut valves are disposed at intermediate positions in hydraulic lines such that wheel cylinders for driving wheels and wheel cylinders for follower wheels are hydraulically communicated with each other. The hydraulic lines can be opened or closed by actuating the air pressure control type cut valves, and air pressure delivered from the traction control valve is applied tot he air pressure control type cut valves so as to allow the hydraulic paths to be closed by the air pressure control type cut valves only when the vehicle is held in the traction controlling state.

Abstract: An automatic and dynamic health monitoring system for detecting wheel lockup conditions caused by an unintentional unreleased handbrake or an unexpected traction motor seizure on multiple-axle railway vehicles by logically sensing and determining the status and operations of the input sensors and indicators to quickly and accurately diagnose the situation and to initiate an output fault code log signal.

Abstract: A sensor in the drawbar (or fifth-wheel coupling) of a tractor-trailer road vehicle combination senses both push and pull force in a linear proportional manner and produces an electrical signal which is used to act on a continuously proportional solenoid valve in the fluid pressure supply to the trailer brakes to control the trailer braking continuously, during application, in a sense tending to reduce the force in the drawbar to zero. There may be a base pressure applied to the trailer brakes, modified positively or negatively by the pressure from the sensor signal.

Abstract: A valve assembly for use in conjunction with spring applied, air release parking brakes of the character found in heavy-duty truck-trailers which, in a single valve housing provides system pressure protection, prevents compounding application of the brakes and performs the parking brake release function in an expedicious and highly reliable manner.

Abstract: A method determines an instantaneously optimum pressure of brakes of a trailer connected to a tractor. Regulation to a desired value of a coupling force existing between the tractor and the trailer is performed by varying the braking pressure of the trailer. A target value, in a braking process, of the pressure of the trailer brakes is determined at least indirectly from the assignment of pressure of the trailer brakes during at least one preceding braking process in which the coupling force has been set equal to its desired value.

Abstract: An anti-lock brake powering system for use on a tractor having a power source and power cord with a connecting device with multiple circuits between the tractor and a trailer with one circuit providing power to the brake lights of a trailer and a switch disposed in the tractor to provide power to the brake lights of a trailer equipped with a conventional brake system when the switch is in one position so that when the brakes of the tractor are applied a pressure sensitive switch disposed in the tractor is activated and lights the brake lights of the tractor and lights the brake lights of the trailer equipped with a conventional brake system and so that when the switch is moved to a second position, continuous electrical power is supplied to the anti-lock brake system of a trailer equipped with an anti-lock brake system and when the brakes of the tractor are applied the pressure sensitive switch disposed in the tractor is activated and lights the brake lights of the tractor and a pressure sensitive switch disp