Abstract: A dual-circuit master valve for hydraulically actuated power brakes is diosed. An equalizing device in the valve assures a uniform build-up of pressure in both brake circuits. Even if one brake circuit fails, the equalizing device assures dependable operation of the remaining brake circuit without additional parts. The equalizing device includes at least one pressing member which acts on two conical valve slides, each having an opening facing the pressing member. The end of the pressing member facing the valve slides is provided with elastic material, preferably rubber or plastic, which deforms to equalize pressure when the pressing member presses against the openings in the valve slides.

Abstract: A brake control arrangement for use with a multiple disk brake system having a plurality of disk brake actuators which exert a braking force in relation to the fluid pressure presented to a service braking portion contained therein. A handle valve is operable over a range of travel for delivering a braking fluid pressure to be directed to a first input of one of a purality of shuttle valves. This braking fluid pressure, however, is first directed through one of a plurality of flow paths selected by a selector valve arrangement. The selector valve arrangement can be sequenced to direct the initial braking fluid pressure through a different one of the plurality of flow paths upon receiving a sequencing count signal transmitted from a counter valve arrangement. A pilot operated relay valve has a pilot portion which receives the braking fluid pressure and opens the relay valve when the braking fluid pressure reaches a predetermined value.

Abstract: A dual brake valve assembly for use in fluid pressure-operated vehicle braking systems embodying two independent braking circuits comprises a housing provided with sets of primary and secondary ports associated respectively with the two braking circuits and each consisting of a supply port for connection to a source of fluid under pressure and a delivery port for connection to a brake actuator, an exhaust, and two co-axial primary and secondary valves which are operative, when actuated, to isolate the delivery ports from the exhaust and connect them to the respective supply ports. A primary piston operates the primary valve directly and acts through the primary valve and a secondary piston to operate the secondary valve. The secondary piston is provided with passages through which the respective supply and delivery ports of each set are placed in communication when the respective primary and secondary valves are operated.

Abstract: A dual circuit brake valve which is provided with a relief connection intended for two separate individual valves and in which two outlet valve seats are disposed centrally in the valve. The two outlet valve seats are prestressed with respect to one another by way of a bolt and a prestressed pressure-limiting spring in such a way that at a time braking begins the two individual valves represent a rigid connection. From a pressure limitation point on, the two individual valves then support themselves elastically against one another, so that a further increase in braking pressure is precluded. The dual circuit brake valve is intended for brake systems having high pressure as a reservoir pressure and normal pressure as the braking pressure.

Abstract: In dual control assemblies for hydraulic braking systems of vehicles, the valve assemblies comprise a pair of control valves clamped together in side-by-side relationship in each of which a back-up piston works in a greater diameter portion and a hollow spool works in a smaller diameter portion of a stepped bore, the piston and the spool being operated by a push- or pull-rod in turn operated by a pedal. The spool controls communication between pressure spaces of the valves and their respective recuperation, inlet and transfer ports. The recuperation ports are connected to a common reservoir for fluid, the inlet ports are connected to a common hydraulic power source and the transfer ports are interconnected. Each pressure space is connected to a brake via an outlet port.

Abstract: A pressure-medium brake system with division into two or more brake circuits is proposed. A relay valve is incorporated into each brake circuit. Control medium and working medium of each relay valve are supplied by the same pressure-medium source. For each brake circuit a single valve is provided in a service brake valve, which additionally has an electrical supply, with which the actuation of all relay valves can be controlled. The pressure-medium brake system is perferably embodied as an air-brake system and is intended for utility vehicles, such as trucks and buses.

Abstract: A control arrangement of a hydraulic vehicle braking system provided with antiskid control equipment includes a master cylinder device which is actuatable by a brake pedal and is provided with at least one master piston cooperating with an associated replenishment chamber. The replenishment chamber is hydraulically connected through a substantially radial bore with the secondary side of the master piston. An axially displaceable circumferentially sealed positioning piston is disposed at the secondary side of the master piston, and a piston rod of the master piston concentrically and sealingly passes through the positioning piston.

Abstract: An hydraulic braking system for vehicles comprises a single pedal-operated master cylinder, a selector valve assembly and a double-acting valve incorporated into a common housing, and an actuator for a brake on either side of the vehicle. A lever acts to close a diverter valve to cut-off the supply of fluid to the actuator on one side when the brake on the other side is to be applied, so that one brake is applied independently of the brake on the other side. Each actuator comprises a differential piston which works in a stepped bore to apply the brake, and when one of the valves closes, the lever simultaneously acts on the double-acting valve to increase the effective area of the actuator for the applied brake. A greater output torque is therefore obtained from the brake on one side when the brake on that side is applied independently than when the brakes on both sides are applied simultaneously.

Abstract: A brake valve useable in conjunction with a vehicle braking system is monitored by an anti-locking device and operable by a brake pedal through a trailing or simulating spring. The brake valve is provided with a control slide valve for regulating a metered feed of the pressure medium conducted from a pressure source to the wheel brake cylinders of the braking system. The pressure medium is furthermore relievable at the wheel brake cylinders by anti-lock valves. The control slide valve cooperates with at least two emergency pistons freely traversible during normal operation of the braking system. Each of these emergency pistons are mechanically operable from the brake pedal in case of failure of the energy supply or of a brake circuit after a valve associated with the respective pistons has been closed.

Abstract: A brake valve useable in conjunction with a vehicle braking system monitored by an anti-locking device and operable by a brake pedal through a trailing spring sometimes also called a simulating spring. The brake valve is provided with a control slide valve longitudinally displaceable by the trailing spring. The slide valve regulates a metered feed of the pressure medium conducted from a pressure source to the wheel brake cylinders. The pressure medium is relieveable at the wheel brake cylinders by anti-lock valves. The slide valve includes two control slide valves of which is associated with a pressure reservoir. One control slide valve cooperates with an emergency piston providing free through-flow during normal operation of the braking system. The emergency piston, upon a failure of the pressure medium source, after an emptying of the pressure reservoirs, is operable mechanically by the brake pedal after a spring-loaded ball valve has been closed at the emergency piston.

Abstract: Dual circuit pressure control valves for brake system are known in which the control pistons are located parallel to each other with each control piston controlling a different one of two brake circuits. Both control pistons are loaded by a common preloading force. The known arrangement is complicated in its construction and has a large overall length. According to the present invention, the construction is simplified and the overall length is reduced by providing a torsion spring which provides the preloading force acting on the control pistons via stationarily supported swivelling levers.

Abstract: A vehicle pressing cylinder, such as, for an automobile, installed between a master cylinder and the wheel cylinders thereof comprises a body defining three cylinders, e.g. a front cylinder, and right and left rear cylinders, the front cylinder having a larger bore than each of the right and left rear cylinders, a panel member covering one end of the body having passageways to concurrently direct brake fluid to each of the three body cylinders, and pistons reciprocably mounted in each of the three body cylinders. Means are provided repair any of the three body cylinders upon damage to brake lines and discrete warning means are provided to warn the vehicle operator of such damaged brake lines.

Abstract: A hydraulic brake force amplifier is proposed, which has a control valve actuatable via a travel-imparting spring which directs the exertion of pressure medium from a supply source as an auxiliary force.The travel-imparting spring disposed subsequent to the brake pedal provides sensitive response by the control valve. If the auxiliary force fails, the action of the travel-imparting spring is precluded, so that pedal travel is not used unnecessarily.In order to effect this preclusion, a barrier piston is used, which is exposed on one side to the force of a spring and on the other side to a varying pressure, so that it does not seize due to corrosion and always remains in a functionally ready condition.The combination of the brake force amplifier with an anti-wheel-lock apparatus is possible.The hydraulic brake force amplifier is preferably applicable in vehicle braking systems for passenger cars and light trucks.

Abstract: The corrector comprises two identical parallel pistons which control the opening and closing of two valves located between two inlets and two outlets of two braking circuits. Two push rods subjected to a control pressure urge the pistons in the direction for opening the valves. A reaction spring cooperates with a transmission element to urge the push rods in the opposite direction. When both braking circuits are being supplied, the corrector presents an identical cut-off point for the two circuits. In the event of one of the circuits failing, the transmission element undergoes tilting which results in an unequal sharing of the reaction force and an increase in the cut-off point in the undamaged circuit.

Abstract: With a known brake pressure control valve for a dual-circuit brake system, a tilting lever device is provided for the distribution of the preloading force on the control pistons, which increases the change-over point of the brake circuit in operation when the other brake circuit fails. This tilting lever device is complicated in construction and assembly and is not safe in its operation. Therefore, in accordance with the present invention the device for distributing the preloading force comprises two tops each of which is fixed to a different one of the two control pistons. The tops have supporting surfaces on which the preloading device abuts. The adjacent areas of the tops are meshed in such a way that the supporting surfaces of each top extend beyond the median plane located between the control pistons.

Abstract: In a known tandem master cylinder with a regulator, machining and assembly of the parts is complicated which renders the master cylinder costly. Moreover, such an arrangement is only realizable with master cylinders having a large diameter. There are also functional disadvantages, particularly in the event of failure of one brake circuit, the brake fluid volume consumption of the other brake circuit is materially increased which results in an additional increase of the pedal travel. To avoid these shortcomings, the present invention provides a tandem master cylinder with a regulator including an arrangement, which in the event of failure of the front-axle brake circuit, mechanically actuates the regulator valve coupled to the rear-axle brake circuit by a pressure piston to keep the regulator valve in the open position to enable unreduced braking pressure to be coupled to the rear-axle brake circuit.

Abstract: Spool type brake valve for use in motor vehicle braking systems. The valve has an exhaust valve assembly and an inlet valve assembly. The former having a spool displaceable by a brake pedal or the like to disconnect the brake-port from an exhaust port and the latter having a spool movable within a sleeve upon subsequent displacement of the exhaust valve to supply pressure fluid to the brake port.

Abstract: PCT No. PCT/US79/00598 Sec. 371 Date Aug. 13, 1979 Sec. 102(e) Date Aug. 13, 1979 PCT Filed Aug. 13, 1979Conventional fluid control circuits for brakes and the like normally comprise a control valve interconnected between a pressurized fluid source and the brakes for selectively actuating the same. A problem arises in that upon starting of the vehicle during cold weather conditions, the hydraulic fluid is not sufficiently warm to ensure efficient brake operation. This invention includes conduits (36) for sequentially communicating fluid from a fluid source (11), through an actuating chamber (14) of a brake (15), and to a control valve (25) in series when the brake (15) is either in its disengaged or engaged condition of operation. Furthermore, upon actuation of the valve (25), an operator is enabled to detect by "feel" the degree of brake engagement.

Abstract: A brake valve comprising two coaxial, tandemly arranged control spools each connecting a different one of two brake circuits to either an associated pressure fluid source or an associated unpressurized reservoir. A first of the two control spools is actuated mechanically by a brake pedal and the second of the two control spools is actuated by the brake pressure controlled by the first of the two control spools. In order for the second of the two control spools to meter the same pressure into the associated brake circuit as the first of the two control spools, the second of the two control spools has two additional effective surfaces, one of which is acted upon by the brake pressure controlled by the first of the two control spools in the direction of actuation and the other of which is acted upon by the brake pressure metered into that one of the two brake circuits controlled by the second of the two control spools.

Abstract: A safety device for a double-circuit type air brake, wherein compressed air is supplied from one compressor to a pair of air reservoirs, through a check valve in each respective route, featured in inserting a safety device in an upstream portion of the double-circuit brake system, i.e., nearer to the compressor than the check valves.

Abstract: In a control valve assembly for vehicle hydraulic braking systems pressurization of a distributor chamber in a housing is controlled by a valve operating mechanism. The valve operating mechanism comprises a piston working in the distributor chamber, a recuperation port in the wall of the housing for connection to a reservoir for fluid and communicating with the chamber on one side of the piston, an axial bore through the piston providing communication between the recuperation port and an inlet passage for connection to a source of high pressure fluid, an axially movable valve member for alternate engagement with first and second axially spaced seatings, the first seating comprising a seating surrounding the opening in the piston and the second seating leading to the inlet passage, and a spring for urging the valve member normally into engagement with the second seating with the valve member spaced from the first seating.

Abstract: A hydraulic servo-assisted braking system for motor vehicles has a master cylinder controlling two independent braking circuits through respective auxiliary cylinders each having an auxiliary piston with a central bore and an associated servo-piston with a stem which closes the said bore upon displacement of the servo-piston by hydraulic fluid pressure of source circuit, separable from the master cylinder, applied to the servo-piston through a common interception valve which is opened to admit the source pressure to the servo-pistons upon movement of either or both of a pair of pistons in a modulator cylinder subjected to the respective hydraulic pressures in the two brake actuator circuits. Failure of one of the braking circuits allows the other to remain operative, while damage to the servo-cylinders allows braking to remain effective through the master cylinder.

Abstract: In a control valve assembly for a vehicle dual hydraulic braking system separate brake-applying valves in a common body are operable independently or simultaneously to cause hydraulic fluid from a distributor chamber to be supplied to one or both of a pair of outlets for connection to brakes on wheels on opposite sides of the vehicle. Each brake-applying valve comprises a valve member which is urged into engagement with a seating surrounding a respective outlet by means of a spring. An operating member for moving the valve member away from the seating in a brake applying direction is coupled to a respective brake pedal, and the operating member is also coupled to the valve member through a lost-motion connection.

Abstract: A control valve assembly for a vehicle dual hydraulic braking system in which hydraulic fluid from a distributor chamber can be supplied to one or both of a pair of outlets for connection to brakes on opposite sides of a vehicle. The assembly incorporates a pressure control valve operable to supply fluid under pressure to the chamber from an outlet for connection to a pressure source, irrespective of whether one or both of two separate brake-applying valves are to be operated, and a one-way valve is located on the upstream side of the pressure control valve to prevent flow in a reverse direction. A back-up piston works in a bore in communication with the chamber, and is provided to pressurize fluid in the chamber after an exhaust valve has closed and a pressure control valve has opened.

Abstract: A control valve assembly for vehicle dual hydraulic braking systems is operated by a lever mechanism. The lever mechanism comprises first and second levers which are pivotally connected to each other by a first pivot. One lever acts on a valve mechanism for controlling pressurization of a distributor chamber, and the other lever is pivotally connected to a housing through a second pivot. Each lever acts on a respective one of a pair of brake-applying valves for controlling the supply of pressure fluid in the chamber to an outlet in the housing for connection to a wheel brake.

Abstract: The invention relates to an actuating device for pressure medium brake systems for controlling the motor-vehicle brake valve and an electric switching arrangement for continuously switching on the individual braking steps of a third brake system.

Abstract: A dual relay valve for controlling the supply of fluid pressure to two sets of brakes is operated by a single source of control fluid pressure. A solenoid-operated valve, controlled by a skid-control logic circuit isolates and vents the control fluid pressure upon detection of skid conditions.

Abstract: A hydraulic control device for a pneumatic brake system, more particularly for use in heavy vehicles. The control device of the hydraulic type is provided between the brake pedal and the pneumatic control valve of the brake circuit, this device comprising a master cylinder associated with the brake pedal and a hydraulic receiver cylinder comprising at least one piston capable of displacing the inlet element of the pneumatic control valve. The receiver cylinder comprises a housing provided with a bore, at least one piston slidable in the bore and an abutment for restricting travel of the piston towards the inlet control element of the control valve.

Abstract: A two-circuit brake system, operable either pneumatically or hydraulically, for motor vehicles including an operator-controlled brake valve for effecting supply of brake-operating pressure via a vehicle load-responsive device for regulating brake-operating pressure to the rear axle according to vehicle load, and a relay valve responsive to such regulated pressure for effecting supply of brake-operating pressure to the front axle according to a predetermined ratio. The relay valve includes certain pressure area members which may be replaced by others for varying the rear axle to front axle braking-pressure ratio to suit the particular vehicle on which it is used, and the operator-controlled brake valve is operable for maintaining effectiveness of at least one of the brake circuits, either front or rear, in the event of failure of the other.

Abstract: A master cylinder for a two-circuit brake system which includes an anti-skid control has two separate chambers and pistons. The main control piston is associated with a booster piston which it engages after a predetermined amount of travel. The brake pedal is arranged to actuate inlet and outlet valves and a selector piston provided with an array of longitudinally disposed rods is arranged to actuate the inlet valve.

Abstract: Braking system, primarily for wheeled excavators, having a first hydropneumatic brake acting on all wheels and a second auxiliary brake acting on the transmission, a first actuating device to operate the first brake when driving on the road and a second actuating device to operate first and second brakes when the excavator is stationary and working on site, the second actuating device being arranged so that on its operation both brakes are applied simultaneously.

Abstract: A hydraulic servo-brake arrangement for a vehicle brake system having two brake circuits comprises a piston-cylinder arrangement with a piston rod for connection to the vehicle brake pedal and with a cylinder inlet from a fluid reservoir and a cylinder outlet to a first brake circuit, and a regulator valve with an inlet from a pressure source and an outlet to a second brake circuit. The pressure in the first brake circuit influences the regulator valve to open the connection between the pressure source and the second circuit, while the pressure in the second circuit urges the piston in the braking direction. The piston is mounted for limited displacement in relation to the piston rod, whereby valve control means are movably mounted together with the piston rod to urge the control valve in the opening direction after a predetermined piston rod travel in the braking direction.

Abstract: A dual brake valve for use in a twin-circuit fluid pressure-operated vehicle braking system comprises a housing, two sets of ports therein each including an inlet port and a delivery port, and two co-axial valve assemblies associated respectively with the two sets of ports, the valve assemblies each comprising a poppet-type valve element the head of which is subjected to delivery pressure, which pressure also acts on an oppositely-directed face of the valve element such that fluid pressure across the valve element is balanced. Preferably an axial exhaust passage is provided in part by a tubular member located co-axially between the valve assemblies by a diaphragm assembly which is also subjected to delivery pressure on both sides thereof.

Abstract: Brake operating system for use in electrically driven vehicles having an electric brake and a pneumatic brake. Both the electric and pneumatic brakes are respectively operated by their respective operating apparatus different from and independent of each other when a brake pedal is depressed. The operating apparatus of the electric brake comprises a rheostat and a mechanism for mechanically operating the rheostat by depression of the brake pedal, while that of the pneumatic brake comprises a compressed air, pneumatic circuit divided into two lines independent of each other so as to respectively introduce the compressed air into two pairs of power clusters which are respectively connected to respective brakes for front and rear wheels, and a pair of brake valves respectively provided in the pneumatic circuit lines and simultaneously operated by depression of the brake pedal.

Abstract: A brake control valve device for a use with tandem or tractor-trailer type vehicles employing dual brake systems with the source of operating fluid supplied at a relatively higher pressure than that required for operating the brakes. The respective valve elements of the valve device for controlling supply and exhaust of operating pressure to and from the respective brake circuits are mechanically actuated through a manually actuated pressure graduating piston (for the first brake circuit) and a fluid pressure responsive relay piston (for the second brake circuit), the dimensions of the relay piston being limited to less than normal for conserving space, but being provided with an adjusting mechanism for adjusting the fluid pressure responsive operating range thereof for compensating for the smaller dimension and synchronizing the relative serial operation of the dual brake circuits.

Abstract: A compressed air supply system, including a compressor and a pressure regulator, is coupled to a multi-circuit brake valve. Each circuit of this multi-circuit brake valve includes a double valve and an associated safety valve positioned in coaxial relationship therewith. The safety valves are each coupled to an associated supply tank and are coupled in common to the compressed air supply system by a spring-loaded needle valve.

Abstract: A safety brake pedal for power-assisted brake systems of motor vehicles of the type having a source of fluid under pressure includes a member adapted to transmit the brake control effort and associated with and normally locked to the brake pedal by an assembly responsive to the fluid from the source. The interlocking action is removed in case of accidental drop or failure in the fluid pressure, the extra free stroke of the brake pedal thus permitted being utilized for actuating a safety brake.

Abstract: The brake system includes a tandem master cylinder and a control valve for introducing pressure supplied from a power source. The main feature of the present invention is that the pressure from the power source is first introduced into annular chambers behind the sleeve seals of both the tandem master-cylinder pistons. This makes it possible for the pistons to travel only a small distance if power from the power source is available. Thus, the pistons can be dimensioned in accordance with the force the driver is able to exert with his foot in the event of failure of the power source.

Abstract: A change-over valve including a housing and a slide sealingly guided therein is provided for use with a two-line trailer brake system having two brake circuits. The slide is retained in a normal position, at which supply tubes leading to compressed air supply tanks for the brake circuits are closed, by a piston loaded with compressed air from a supply tube, but is manually movable to a maneuvering position, at which the brakes of the system are released. The slide is provided with two channels and two associated check valves arranged so that when the slide is in the normal position it closes the supply tubes leading to the compressed air supply tanks for the brake circuits and so that when the slide is in the maneuvering position it connects those supply tubes via its channels and the associated check valves to a common space, which is connected to one or more emergency brake chambers for emergency brake pistons of the trailer brake system.

Abstract: A brake application valve is used to connect supply tanks to the front and rear brakes of a vehicle. The valve has a pair of shuttle members which normally close communication between the inlets and the outlets and open communication between the outlets and exhaust. There are two pistons, movement of which is effective to cause the shuttle members to open communication between the inlets and outlets and close communication to exhaust. One of the pistons (second piston) has inner and outer portions, with the inner portion being provided with a mechanical connection to the first piston such that movement of the first piston can cause movement of the second piston inner portion. The outer portion of the second piston is exposed to pressure at one outlet to cause movement of the second piston in response to air pressure at the first outlet.