Abstract: A fluid pressure braking system for a vehicle having service brakes and spring activated parking brakes includes electropneumatic activators for effecting and holding a limited service brake application while the driver leaves the vehicle to make a route pick-up. Accordingly, the spring brakes are not used during route pick-ups, thereby increasing the life of the spring actuator since it is not repeatedly cycled. An electropneumatic interlock automatically effects a parking brake application if the vehicle ignition is switched off while an electropneumatic service actuation is effected.

Abstract: A dual pressure vehicle air brake system (60, 61, 100, 101) made according to the invention includes first and second sources (62, 64) of pressurized air at, for example, 175 psi and 100 psi, respectively. A combination brake actuator (6) includes a conventional service brake chamber (8) adapted to accommodate the lower, second air pressure while the spring brake chamber (10) is made to accommodate the higher, first pressure. The use of the higher first pressure allows a stiffer actuator spring to be used and be fully deflected by the first pressure without substantially changing actuator piston areas and other elements of conventional combination brake actuators. A conventional modulated spring brake control valve (78) is used to supply air at the first pressure to the spring brake chamber. The service brake chamber is supplied with air at the second pressure through the outlet of a conventional service brake application valve (68).

Abstract: A hydraulic braking system for controlling the hydraulic pressure of the brake actuator and wheel cylinders includes a dynamic hydraulic pressure control system which transmits boosted hydraulic pressure in response to movement of a brake pedal. A master cylinder receives brake fluid pressure from a reservoir and transmits the fluid pressure from a pressure chamber in the master cylinder to a changeover valve. The changeover valve changes over the connection between wheel cylinders of the vehicle and the dynamic hydraulic pressure control system when the powered pressure which is transmitted from the dynamic hydraulic pressure control system is less than a predetermined pressure. A valve member of the changeover valve is movable between a first and second position so as to transmit the powered hydraulic fluid from the boost pressure chamber to the wheel cylinders of the rear wheels in a first position and block the transmission of the fluid in the second position.

Abstract: The brake activation apparatus comprises first and second brake devices capable of being selectively applied, a shifting mechanism for selectively applying either the first or second brake device and not the other, a mechanism for overriding the shifting mechanism for applying both of the first and second brake devices, and a mechanism for releasing the override during both normal and manual operation. The apparatus is useful in a power drive unit comprising a carrier having first and second planetary gears rotatably mounted on the carrier, first and second rotatably mounted sun gears in meshing engagement with the respective planetary gears, the sun gears each having a drive output portion for driving respective devices and a braking portion for cooperation with the first and second brake devices to control the output of the power drive unit by selectively braking the respective sun gears.

Abstract: In the braking systems of many vehicles, a parking brake is utilized that is spring applied and fluid pressure released. In the event of a mechanical breakdown, a mechanical device or other specialized tools must be used to bring about the disengagement of the parking brake so that the vehicle may be towed. The present invention overcomes this problem by providing an auxiliary actuating mechanism for a spring applied, fluid pressure released parking brake that includes an auxiliary accumulator that will maintain a preselected amount of pressure upon the loss of the primary source of pressure. An auxiliary actuating valve is positioned between the accumulator and the parking brake to selectively communicate fluid therebetween. The auxiliary actuating mechanism is provided with two remotely located actuators that may be utilized to selectively position the valve to permit the communication of the pressurized fluid within the accumulator with the parking brake assembly to achieve the disengagement thereof.

Abstract: A control system includes a hydraulic pump that is driven by the output shaft of the vehicle transmission. A plurality of valve members control the inlet and outlet fluid flow of the pump so that during vehicle braking, a hydraulic retarder is supplied by the pump with hydraulic fluid drawn from a reservoir. When vehicle braking is not requested, the pump inlet is connected to the retarder to evacuate and lubricate the interior thereof.

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: A railroad truck having at least four wheels comprising brakes for braking the wheels; a single enclosed air cylinder mounted on the truck; the air cylinder having first and second chambers; a conduit to supply service air pressure to the first chamber; the first chamber containing a piston pneumatically operated by service air pressure to apply controlled service braking pressure, emergency braking pressure and, when the truck is stopped, parking braking pressure, to the brakes; the second chamber containing a spring which applies automatic parking pressure to the brakes when the truck is stopped, and applies emergency fail-safe pressure to the brakes when there is a pneumatic system failure to supply air to the first chamber; apparatus to supply pressurized air to the second chamber to keep the spring from applying pressure to the brakes so long as adequate air pressure is maintained in the second chamber; a handbrake assembly mounted on the truck in a position readily accessible for manual operation when t

Abstract: A relay valve is provided within a single housing and includes a brake cylinder relay valve with combined highway override, a dual pressure brake cylinder limiting valve responsive to load, highway supply line and rail supply line charge check valves and a rail reservoir protection valve. The brake cylinder relay valve includes a valve spool positioned by a first piston responsive to the control signal from a control valve to determine the flow to the brake cylinder and a second piston responsive to the highway supply line to connect the brake cylinder to exhaust. The limiting valve includes a first piston responsive to load signals to define the first set of limits and a second piston in tandem with the first piston responsive to load signals and emergency brake signal in the brake pipe for increasing the response of the first piston to the load signals in response to an emergency signal on the brake pipe.

Abstract: A vehicle brake system includes a check valve having an input port coupled to a fluid pump outlet and an output port coupled to hydraulically deactuated spring brakes through brake lines. A pilot check valve has a pilot port, an inlet port coupled to the input port of the check valve and a return port coupled to the fluid reservoir. The pilot port is coupled to the output port of the check valve so the pilot check valve opens only when the output port is pressurized. This allows hydraulic fluid to flow from the pump, through the pilot check valve and to the reservoir. To set the brakes when stopped or in emergency situations the operator actuates a valve which dumps the fluid in the brake lines into the reservoir. A second pilot check valve has its pilot port connected to a brake pedal actuated master cyinder, its inlet connected to the brake line and its outlet connected to the reservoir.

Abstract: A motor vehicle comprises two driven axles (5, 8), which are interconnected by an interaxle coupling (10) for transmitting a torque only when the halves of the coupling (10) rotate at different speeds and by a speed-changing transmission (9) connected in series with the coupling (10). A brake system (12 to 15) is provided for braking the wheels of both axles (5, 8). In order to ensure that the wheels of the driven rear axle (8) will not block before the wheels of the driven front axle (5), a pressure-setting controller (17) is adapted to control a brake pressure regulator (16) associated with the driven rear axle (8) and is responsive to a reversal of the direction in which torque is transmitted to and from the driven rear axle (8).

Abstract: An improved friction brake system for a transit vehicle is disclosed. The conventional friction brake system for a transit vehicle utilizes an integral service brake and emergency-parking brake actuator. The service brake portion is air powered while the emergency-parking brake portion is spring powered. It has been conventional to apply full service air brake and emergency spring brake during emergency stops. An accelerometer switch is typically connected in circuit with the service brake portion to prevent the service brake from turning on if their is sufficient deceleration. The accelerometer switch often does not react quickly enough to prevent the onset of the service brakes. The present invention utilizes a time delay switch to delay the onset of service brakes until after the spring-activated emergency brakes react.

Abstract: A mechanical emergency and parking brake system, for vehicles of the type having a power steering pump, includes a check valve having an input port coupled to the pump outlet and an output port coupled to hydraulically deactuated spring brakes through brake lines. A pilot check valve has its inlet port coupled to the input port of the check valve and an output or return port coupled to the power steering gear. The pilot port of the pilot check valve is coupled to the output port of the check valve so that the pilot check valve opens only when the pressure at the output port of the check valve is above a chosen pressure. This allows hydraulic fluid to flow from the pump, through the pilot check valve, through the power steering gear and to the reservoir. To reapply the brakes, the operator actuates a valve which disconnects the brake ports from the output port of the check valve and connects the brake lines to the reservoir.

Abstract: According to progress of a vehicle, a pump is actuated to feed fluid into a brake pipe. The discharge of the pump is generally proportioned to vehicle speed. On the other hand, the fluid within the brake pipe is relieved to an upper stream side of the pump at a predetermined flow rate regulated by an orifice. Accordingly, when the flow rate of the fluid fed by the pump is less than the predetermined flow rate, in other words, when the vehicle speed is less than the predetermined speed, pressure within the brake pipe is not increased. However, when the discharge of the pump exceeds the predetermined flow rate, the pressure within the brake pipe is increased. Due to this increased pressure, a vehicle wheel braking device is actuated to brake the wheels. Thus, vehicle speed is lowered.

Abstract: A two-way check valve is utilized with each brake assembly to apply pressure against a single actuating diaphragm. One inlet port is connected to the service air supply and one inlet port is connected to the emergency air supply. Satisfactory pressure of either supply operates the brake connected to the brake assembly in a service manner, the loss of air pressure in either supply causing that supply to be closed by the check valve. Emergency air venting from a spring-biased piston with a pawl end causes the pawl to engage a rack surface of the brake actuator rod. Hence, no spring is used to power the brake actuator rod and brake connected thereto closed when there is a loss service air pressure.

Abstract: A brake device for vehicles comprises a master cylinder, a wheel brake adapted to be operated by the output hydraulic pressure from the master cylinder to apply a braking force to a wheel, and an antilock control unit, having therein an inertia type wheel angular deceleration sensor driven by the wheel through a transmission device and adapted for controlling the output hydraulic pressure from the master cylinder in accordance with the output of the sensor, the antilock control unit being carried on the support system for the wheel. Defined on one side of the wheel is a recess which is concave toward the other side of the wheel from the central rotational plane of the rim of the wheel, and the antilock control unit and transmission device are disposed in the recess.

Abstract: Apparatus for controlling supply of air to front brakes in an air brake system of a truck when a manually operable valve (16) is operated to inhibit flow of air to the front brakes comprises a by-pass loop (17, 17') including an electrically operable valve (19). The valve is operated when a switch (28) is closed on moving a gear selection lever (29) to a position to select reverse gear.

Abstract: An auxiliary air brake system is provided for a mobile vehicle which has a drive selector having reverse and other positions and which has a main air brake system which includes a plurality of compressed air tanks, main conduit including a foot brake line and a hand brake line for connecting at least one of the tanks to wheel brake chambers, and air control valves in the main conduit for controlling air pressure at the wheel brake chambers.

Abstract: A system is shown for automatically applying the brakes of a vehicle moving in reverse, when there is an obstruction in the path of the vehicle. Obstructions are detected by an ultrasonic sensing device which operates a valve, which causes the brakes to be applied. In one embodiment for use with hydraulic brakes, a dual accumulator utilizes both power-steering fluid and braking fluid in the operation of the system, without mixing the two fluids. In another embodiment, the system is used with a pneumatic braking system. In both embodiments, the system is activated only when the vehicle is in reverse gear. In still another embodiment, for use with hydraulic brakes, the brakes are applied solely by pressure from the power steering system of the vehicle.

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: An improved system for control of a drum having a disk brake and pawl engageble therewith, including a pressure sensing switch electrically connected with a solenoid valve which is hydraulically connected with a pump and an accumulator teed into the supply from the pump. A solenoid valve, when energized hydraulically connecting a pawl cylinder attached to the pawl with pump pressure and when de-energized directing fluid pressure to apply the brake and dumping the pawl cylinder to reservoir to engage the pawl. Orifice means control the rates of flow to and from the brake and pawl cylinder to avoid shock loads and to assure the drum is stopped before the pawl is engaged.

Abstract: A brake system in which brake means such as disc brakes are provided with emergency control means which may be a part of the overall system or may be provided by separate self contained sources of pressure which may be valved to the brake means by actuation of an emergency switch. The system provides for control of multiple groups of brake means with multiple control systems each of which are operated at a pressure less than that available from the power source. Pressure between the several groups of brakes are sensed and when a selected differential is noted the full source pressure is applied to the entire brake system. This additional source pressure applied to an undamaged bank of brake means will compensate for loss of a group of brake elements and provide approximately the same braking efficiency. Provision is made to contain pressure within one of the separate systems upon the sensing of conditions indicating a leak.

Abstract: A pressure medium brake system for motor vehicles is proposed in which a high-pressure-producing apparatus and a normal-pressure brake apparatus are provided. The brake pressure is reduced with the aid of pressure limiters from high pressure to normal pressure. In order to attain rapid filling of the brake cylinders, one relay valve is disposed before each group of brake cylinders, the relay valves being triggered with normal pressure and very rapidly directing the high pressure into the brake cylinders with a large pressure drop. Upon attaining the maximum pressure level of the normal pressure, the supply of high pressure in the relay valve is cut off. The pressure medium brake system is preferably used as a compressed-air brake system for trucks and trailer-trucks.

Abstract: A hydraulic dual-circuit servo brake apparatus is provided with a control valve, which is intended for directing the pressure medium of a pressurizing device into the brake circuit. The control valve is embodied as a magnetic valve, which is actuatable via signal transducers, valves, or the like in accordance with the given position of the main cylinder pistons. The control valve may be combined with an anti-skid apparatus such that the magnetic valve is also actuatable in accordance with the functioning of the anti-skid means. An integration of the magnetic valve with multiple-position valves of an anti-skid control means is possible.

Abstract: A control system (10) for a spring applied, pressure released brake (16) is provided to control the pressure level in the brake (16) in response to operation of a control valve (22) to stage the pressure levels relative to the operating mode of the control valve. The control system (10) also provides two different fluid pathways (58,60) that are individually operational to lubricate a winch and draw-works mechanism (18) in response to the operating position of the control valve (22). This system improves the response time needed to gradually release the brake (18).

Abstract: A fluid system for the rail brake cylinder of a highway/rail vehicle including a control valve responsive to brake pipe pressure drops to provide a control signal to a variable load relay valve assembly which provides brake cylinder pressures. The relay valve assembly maintains the rail brakes deactivated in the highway mode, provides braking pressure independent of the variable load portion for low pressure in the control valve's auxiliary reservoir, maintains a rail reservoir and rail suspension supply changed from the highway and rail supply lines, and creates an emergency condition in the brake pipe for low rail supply line and or rail reservoir pressure.

Abstract: A system suitable for positively holding an earthmover in a fixed position during excavating or loading operation, comprising a first air reservoir in communication with a parking brake via a parking control valve. A second air reservoir communicates with front and rear wheel brake cylinders via a dual brake control valve assembly and pneumatic-to-hydraulic converters. A pilot-operated source selector valve coacts with shuttle valves to normally allow communication between the brake control valve assembly and the converters and, upon application of the parking brake by the parking control valve, to place the first air reservoir in communication with the converters. Thus the actuation of the parking control valve results in the application of not only the parking brake but also the service brakes.

Abstract: A fluid system for the rail brake cylinder of a highway/rail vehicle including a control valve responsive to brake pipe pressure drops to provide a control signal to a variable load relay valve assembly which provides brake cylinder pressures. The relay valve assembly maintains the rail brakes deactivated in the highway mode, provides braking pressure independent of the variable load portion for low pressure in the control valve's auxiliary reservoir, maintains a rail reservoir and rail suspension supply changed from the highway and rail supply lines, and creates an emergency condition in the brake pipe for low rail supply line and or rail reservoir pressure.

Abstract: A hydraulic single-current or multiple-circuit brake system, preferably for a motor vehicle, which brake system includes a master brake cylinder operated by a brake pedal and individual brake circuits leading from the master brake cylinder to wheel brake cylinders. An accumulator is provided for enabling a build-up of pressure in the brake circuits when the brake pedal is not operated, with the build-up in pressure being controlled by a control unit such as a forward drive control, a distance control, or the like. A pressure modulator is installed in each of the individual brake circuits leading to the wheel brake cylinders at a position between the master brake cylinder and the wheel brake cylinder.

Abstract: A brake unit comprising a hydraulic booster unit connected to hydraulic auxiliary energy and controllable by a brake pedal via a control piston drives a master brake cylinder unit to supply brake pressure to wheel brake cylinders through at least one hydraulic line connected to an output of the master brake cylinder unit. A bypass line connected to the work chamber of the booster unit supplies a preliminary feed of the auxiliary energy to the wheel brake cylinders to overcome the brake clearance. A two way, two position changeover valve is connected to the hydraulic line, the bypass line and the wheel brake cylinders to connect during a braking operation either the bypass line or the hydraulic line to the wheel brake cylinders dependent on the pressure in the two lines. This brake unit requires only a few hydraulic connections external of the unit, has a single construction, has small dimensions, has exact operation and has quick response.

Abstract: Apparatus (1) for automatically releasing a railroad car hand brake (HB) normally maintained in its applied position. An air pressure activated piston (11) acts on a hand brake release (5) to release the hand brake. An air conduit (13) directs pressurized air from a pressurized air source to the air cylinder. A normally closed first valve (25) is connected in the air conduit between the source and the air cylinder. A normally closed second valve (29) is connected in the air conduit between the source and a control inlet of the first valve. A sensor (33) senses an inertial load on the car and opens the second valve when the inertial load sensed exceeds a predetermined acceleration factor. Air pressure directed to the control inlet of the first valve through the second valve, when it is open, opens the first valve if the air pressure level is sufficiently great to release the air brakes of the car.

Abstract: Apparatus (1) for automatically releasing a railroad car hand brake (HB) normally maintained in its applied position. An air pressure activated cylinder (9) acts on a hand brake release (5) to release the hand brake. An air line (13) directs pressurized air from a pressurized air source to the air cylinder. A valve (27) connected in the air line is responsive to the source air pressure. The valve is normally closed but opens when source air pressure reaches a level sufficient to release the air brakes on the car. A draft load sensor (29) is positioned in the air line between the valve and air cylinder. The sensor normally blocks the air line, but unblocks it when a sufficiently great draft load is sensed. The hand brake is released only if source air pressure is sufficiently high and the draft load on the railroad car is sufficiently great.

Abstract: A system for preventing damage to cargo shipped in air-ride suspension semi-trailers loaded on railroad flat cars which comprise at least part of a freight train is provided. The system comprises a coupling element connected to the air brake line of the freight train. The coupling element is connected to an air reservoir mounted on the flat car or on the semi-trailer and supplies compressed air to the reservoir from the brake line of the train. The coupling element includes a valve to prevent air from flowing from the train brake line to the air reservoir when the air pressure in the brake line drops below a predetermined safety level to prevent unwanted activation of the train's brakes. The air reservoir is connected to the air line of the semi-trailer and provides compressed air to the air bags which comprise the air suspension system of the semi-trailer.

Abstract: A brake unit having a hydrodynamic retarder providing brake torque proportional to speed and inlet pressure, and a friction brake providing brake torque proportional to net brake pressure, the brake apply pressure minus retarder inlet pressure. The controls have a brake demand valve providing a brake demand pressure. A retarder valve is biased by brake demand pressure from brake-off position to brake-on position for switching the retarder circuit to fill the retarder and to connect low and high speed regulator valves to regulate retarder inlet pressure respectively to increase in the low speed range and to decrease in the high speed range with increasing speed, and to limit retarder inlet pressure proportionally to brake demand. The controls, in the low speed range, provide friction brake apply pressure proportional to brake demand, so the friction brake net apply pressure and torque decrease to zero and retarder torque increases as speed increases.

Abstract: An emergency brake system for mine shuttle cars and the like wherein the brakes are applied by spring pressure and are normally released only when the hydraulic system for the shuttle car is activated. In the present invention, a hand pump is provided for releasing the brakes when the normal hydraulic system is not activated. This facilitates moving the shuttle car when it is not connected to a source of power. When the car is again connected to a power source and its hydraulic system activated, a shuttle valve initially releases the pressure produced by the hand pump and then returns the system to normal operation.

Abstract: In a hydraulic brake system which combines a spring actuated, hydraulically released parking brake system with a hydraulically actuated service brake system and in which the parking and service brake systems both operate through a common force-transmitting element on the brakes, and in which the fluids in the two brake systems are mutually incompatible, an anti-compounding valve limits the sum of the forces which can be transmitted by the common force-transmitting element when the service and parking brake systems are simultaneously applied and which maintains the fluid in the two brake systems isolated from each other.

Abstract: A fluid control system providing a backup system for activating a pair of brakes on a vehicle includes a pair of double check valves with cross bleed located near the brakes. Each double check valve is connected at one end to a brake control valve which is in turn connected to a main pump and reservoir. The second ends of the double check valves are commonly connected to a secondary brake control valve which is connected to an accumulator which is fluid pressurized from the main pump. The center connections between the two ends of each of the double check valves are connected to one of the pair of brakes. The double check valves respond to pressure differentials to connect the main pump or the accumulator, whichever is supplying the greater pressure, to the brakes.

Abstract: A brake system is disclosed which comprises a primary fluid power brake subsystem and a secondary or back-up brake subsystem. The primary brake system is of the "power brake" type, and includes a power brake valve having a housing defining an elongate bore. A bi-ended rod extends through the housing end wall to be slid between spaced apart first, second and third positions. That end of the rod which is inside the housing is affixed to a reaction piston. The reaction piston cooperates with an annular piston, also carried within the bore, to have fluid flow through the valve and raise fluid pressure within a collapsible chamber defined by the bore. When the rod is partially pulled out of the valve housing, this high pressure fluid is directed to vehicle brakes to cause primary braking action. Should the primary system fail in some respect, rod pull-out action operates to energize a secondary or back-up brake system.

Abstract: A vehicle braking system has a spring engaged and fluid released drive line brake, a pair of fluid engaged and spring released service brakes, and a control circuit for applying only the service brakes over a preselected braking force range and for applying the service brakes and the drive line brake in response to a braking force greater than said preselected range. The control circuit preferably includes an inverter valve, and also an override valve for selectively applying the drive line brake independently of the operation of the service brakes.

Abstract: The anti-skid brake control system is provided with a brake booster operatively connected with a brake pedal and a master cylinder to supply fluid pressure to wheel brake cylinders in response to the pressure generated by the brake booster. The wheel brake cylinders are hydraulically connected with the master cylinder for applying a braking force to the wheels of the vehicle in response to the pressure of the master cylinder. A brake actuator is connected in the fluid circuit between the master cylinder and the wheel cylinders for controlling the pressure in the wheel cylinders and a control valve is hydraulically connected with the brake booster and a fluid pressure source to provide an operating fluid pressure to the actuator whereby the level of the operating pressure is proportional to the level of the pressure generated by the brake booster.

Abstract: Back pressure from the hydraulic power brake assembly of a vehicle acts on brake actuators to hold off spring apply brake assemblies through a vehicle operator actuated control valve. When the parking brakes are to be actuated, the operator turns the control valve so that it vents the hydraulic hold-off chambers to the hydraulic power brake sump, permitting the springs to apply the parking brakes. The hydraulic service brake system includes pistons in the brake actuators for normally actuating the brakes under pressure generated by the hydraulic power brake assembly. The pistons are mechanically acted upon by the spring apply forces when the parking brakes are actuated. The parking brake mode therefore uses the same wheel brake elements as does the service brake mode.

Abstract: The usual brake cylinder in a conventional freight car brake apparatus is replaced by a novel cylinder that embodies a pair of pistons and a spring of sufficient strength to effect a hand brake application. Conventional brake applications and releases are effected accordingly as the usual brake control valve effects the supply of fluid under pressure to and the release thereof from one of the two pistons which are connected to a common piston rod through which force is transmitted to brake applying brake shoes. The second piston is subjected on one side to the force of the spring and on the other side selectively to brake pipe pressure or pressure in a hand brake release reservoir that is charged from the brake pipe to a higher pressure by an air-driven air booster operated by air from the brake pipe. Thus, the spring is enabled to effect a hand brake application in the absence of fluid under pressure acting on the other side of the second piston.

Abstract: A control valve for use in a tow vehicle-trailer braking system has a first bore connected to a master cylinder and a second bore with an entrance port connected to a pump in the tow vehicle for receiving a fluid under pressure, an exit port connected to a power steering control operated by the fluid under pressure, and a control port connected to a servomotor in the trailer. A first piston is located in the first bore and a second piston is located in the second bore. A lever which is located on a pivot pin connects the first piston with the second piston. When the operator applies a braking force to operate the master cylinder, the first piston receives a hydraulic force which acts on the lever to move the second piston and direct a portion of the pump fluid under pressure from the exit port to the control port to activate the servomotor brakes in the trailer.

Abstract: A braking system for the brake of a fluid motor including a jack for releasing the brake and two selectors for controlling the flow of working fluid to the jack. The first selector is responsive to the supply of fluid to the motor to place the jack in communication with a supply pipe and the second selector is responsive to pressure in a bleed pipe connected to the fluid supply to the motor to place the supply pipe in communication with a supply of working fluid under pressure.

Abstract: Braking system for use in track-type vehicles. The system includes a steering brake, a brake cylinder in which an emergency brake piston and a spring for biassing the emergency brake piston to its braking position are provided. The emergency brake piston is operatively connected to the steering brake through a link mechanism and defines with the braking cylinder a hydraulic pressure receiving chamber connected to a hydraulic fluid supply source to maintain the emergency brake piston in its non-braking position against a biassing action of the spring in case of the normal condition of the vehicle. The link mechanism comes into contact with an auxiliary lever serving to move the emergency brake piston to its non-braking position.

Abstract: A sealed, double valve assembly mounted on a vehicle body is connected to a source of pressurized air and controls the air pressure delivered to two auxiliary systems connected to it. The first auxiliary system is a brake force regulator and the second auxiliary system is a headlight beam adjustment mechanism which uses a pneumatic servo-member.Control rods connected to the axle change the degree of compression of a control spring in the double valve assembly, thereby opening or closing valves which admit or release compressed air so as to change the operating pressure of the associated auxiliary systems.

Abstract: A pressure intensifier unit formed of a low pressure air cylinder and a high pressure hydraulic cylinder joined substantially end-to-end, with a large diameter air piston in the low pressure cylinder and a cylindrical piston, in the form of a straight-sided post, secured to the air piston and extending into the high pressure cylinder. An annular gland is provided at the junction between the cylinders for surrounding and sealing the cylindrical piston and for isolating the cylinders from one another. The inner diameter of the high pressure cylinder is greater than the diameter of the cylindrical piston so that, when the cylindrical piston moves into the high pressure cylinder upon application of air to the low pressure cylinder, clearance exists around the cylindrical piston, with hydraulic fluid being volumetrically displaced. The gland serves to mount a pair of axially spaced annular sealing elements with a replenishment port in between them connected to a source of replenishing fluid.

Abstract: A combined emergency and handbrake system employs a friction brake actuator having a spring motor in addition to a hydraulic service motor. The spring motor is restrained from operation by a second hydraulic motor which is normally maintained at operating pressure. By venting the second motor, the spring motor applies the friction brake. This provides failsafe operation for the emergency system, and a positive handbrake system when the car is parked with a de-energized or uncoupled pressure source. The second fluid motor is normally pressurized by application of fluid pressure to the hydraulic service motor. The handbrake may therefore be released by cycling the service brake. This eliminates a need for a second hydraulic or pneumatic actuator for the emergency and handbrake system and assures the safe operation of the car by operation of the service brake before the parking brake can be released. A mechanical retraction device is also provided for special situations.

Abstract: A truck-trailer brake system including a standard hydraulic brake system of the truck, an electrically powered hydraulic brake system for a trailer, the components of which are mountable on the trailer, the trailer brake system being powered by the truck electrical system so as to be automatically actuated in coordination with the truck brake system whenever the truck brakes are applied. The trailer brakes may be operated independently of the truck brakes, as may be desired in special circumstances. Also, the hydraulic power components of the trailer system may be utilized for operating hydraulic accessories of the trailer, and the trailer brakes are applied automatically in case the trailer should break away from the truck.

Abstract: A full-power hydraulic braking system comprises two independently powered service circuits serving separate sets of brakes, a common pedal-actuated dual brake valve controlling operation of said circuits, a spring brake actuator incorporating two hold-off pistons and having a common output to the brakes or brake linkage, and a dual hand control valve for effecting controlled operation of the two sections of the actuator respectively from the two service circuits.