Abstract: A braking system with a brake pump are described. The brake pump may have a first and a second delivery circuit fluidically connectable to at least a first and a second braking device. The first delivery circuit may have an indirect stage fluidically connectable to the first braking device and a direct stage intercepted by a first control valve, fluidically connectable alternately to a braking simulator and to the at least one second braking device. The second delivery circuit may be intercepted by the first control valve so as to actuate the second braking device alternately to the direct stage of the first delivery circuit.

Abstract: A master brake cylinder is described for a brake system of a motor vehicle as having a hydraulic cylinder that has a plurality of hydraulic connections, in which at least one hydraulic piston is mounted so as to be displaceable axially in a direction of actuation and in a relief direction, the hydraulic piston being displaceable against the force of a spring element in the direction of actuation, the hydraulic piston having at least one lateral wall opening that, in at least one sliding position, opens into an inner chamber of the hydraulic cylinder.

Abstract: An electromechanical brake power assist unit of a vehicle braking system has a master brake cylinder with a piston rod, displaceable by a brake pedal and, in the process, building up brake pressure. The piston rod is also displaceable by an electric motor. The piston rod is supported on a pedal lever, which is formed by the brake pedal itself or an intermediate element pivotable about an axis of rotation by the brake pedal. The piston rod is displaced by a pivotal movement of the pedal lever. An axis of rotation of the pedal lever is displaceable by the electric motor in a moving direction of the piston rod.

Abstract: A braking device for a vehicle is provided which includes a braking simulator, thus resulting in improved mountability of the braking device in the vehicle. The braking device is designed to permit component parts of the hydraulic booster to slide on one another in response to a braking effort on a brake pedal, thereby absorbing an undesirable load on the braking device and also ensuring the stability in operating the brake pedal. This results in improved durability and maneuvering feeling of the braking device.

Abstract: A fluid pressure booster for a braking device includes a control piston on which an input brake operation acts in an advancing direction, and a reaction force based on fluid pressure of a booster fluid pressure generation chamber acts in a retracting direction. A pressure increasing valve is provided between a valve chamber communicating with a fluid pressure generation source and the booster fluid pressure generation chamber. A pressure reducing valve is provided between a release chamber communicating with a reservoir and the booster fluid pressure generation chamber. At least one contraction portion is formed between an outer periphery of a front portion of the pressing rod and an inner periphery of a front portion of a valve seat member.

Abstract: A hydraulic brake booster system. The hydraulic brake booster system includes a primary piston axially moveable within a bore of a cylinder, a booster chamber located rearwardly of the primary piston within the bore, an input rod extending within the booster chamber, a booster vent path in selective fluid communication with the booster chamber, and a seal member located between the forward face and the primary piston, the seal member in a fixed relationship with the input rod and configured to (i) seal the booster vent path from the booster chamber when the input rod is in a first position, and (ii) not seal the booster vent path from the booster chamber when the input rod is moved rearwardly within the booster chamber to a second position.

Abstract: A control device (10) for a brake-power-assisted brake system of a vehicle having a first input device (26) for a supplied first information item (28) relating to a supplied assistance force (Fu) of a brake booster (14) of the brake-power-assisted brake system, a second input device (30) for a supplied second information item (32) relating to a total force (Fg) comprising the assistance force (Fu) and a driver braking force (FI) supplied by activation of an activation element (12) of the brake-power-assisted brake system, an evaluation device (36) which is configured to define a third information item relating to a proportional relationship between the total force (Fg) and the assistance force (Fu) taking into account the first information item (28) and the second information item (32), and an output device (44, 50) which is configured to supply at least one control signal (46, 52) to at least one component (14, 54) of the brake-power-assisted brake system taking into account the defined third information ite

Abstract: A braking system having a master cylinder to which wheel brake circuits (I, II) can be connected, a first piston coupled to a brake pedal, a second piston by means of which the master cylinder is actuated, a third piston actuated by the first piston and connected in a force transmitting fashion to the second piston, a simulation device which gives the driver of the vehicle a pedal sensation, an intermediate space between the second piston and third piston, a pressure generating device which controls the pressure in the intermediate space, a pressure medium reservoir vessel which is under atmospheric pressure and which can be connected hydraulically to the intermediate space, and means for electrically controlling the pressure in the intermediate space.

Abstract: A fluid pressure booster for a braking device includes a control piston on which an input brake operation acts in an advancing direction, and a reaction force based on fluid pressure of a booster fluid pressure generation chamber acts in a retracting direction. A pressure increasing valve is provided between a valve chamber communicating with a fluid pressure generation source and the booster fluid pressure generation chamber. A pressure reducing valve is provided between a release chamber communicating with a reservoir and the booster fluid pressure generation chamber. At least one contraction portion is formed between an outer periphery of a front portion of the pressing rod and an inner periphery of a front portion of a valve seat member.

Abstract: Brake apparatus includes a transmission unit for operatively connecting a brake pedal to a master cylinder, and the transmission unit is a mechanism capable of varying a ratio between an output amount of a push rod connected to a master cylinder and an operation amount of the brake pedal. Further, the transmission unit is constructed in such a manner that, in an initial operation region of the brake pedal, a ratio of the operation amount of the brake pedal to the output amount of the push rod is set to be greater than in another operation region immediately following the initial operation region.

Abstract: A vehicle brake system includes a master cylinder having a housing defining a bore therein. A boost piston and a primary piston are slidably disposed in the bore. The master cylinder has a boost chamber defined at least in part by the boost piston and the housing. The system further includes a source of pressurized fluid and a boost valve operable to supply fluid from the source of pressurized fluid to the boost chamber for advancing the boost piston and the primary piston in the master cylinder. According to one aspect of the invention, the boost valve is housed in the boost piston. According to another aspect of the invention, the brake system includes a switchable travel rate feature. According to yet another aspect of the invention, the master cylinder includes a jump in feature. Additional features of the invention are also described herein.

Abstract: A bi-directional braking assembly for a vehicle includes a hydraulic booster assembly for applying proportional fluid pressure to a brake assembly and is actuated by a forward pedal. A master cylinder actuated by a rear pedal communicates fluid to the hydraulic booster assembly through a hydraulic booster valve. The hydraulic booster valve includes a piston movable to regulate hydraulic pressure in response to actuation of first and second plungers. The second plunger is movable along an axis separate from the first plunger in response to actuation of a master cylinder by a rear pedal. The master cylinder provides pressure to the booster valve assembly that acts on an area between the first and second plunger assemblies to move the second plunger away from the first plunger to actuate and move the booster piston within the valve.

Abstract: A master cylinder (12,212) including a housing (40,40a) with a bore (42,42a) for retaining a piston assembly (100,200) to define a first chamber (54) that is connected to wheel brakes (14,14′) in a first brake circuit and a second chamber (56) that is connected to wheel brakes (18,18′) in a second brake circuit. The piston assembly (100,200) includes a sleeve (102,202) and a concentric cylindrical body (110,210) whose respective first and second end surface areas define a first effective area (D1) while the second end surface area of the cylindrical body (110,210) defines a second effective area (D2) within the bore (42,42a).

Abstract: A brake system including an intensifying arrangement which allows a master cylinder pressure to be intensified by feeding a discharge pressure from a pump to an intensifying chamber. The brake system includes a master cylinder having a primary piston, on the rear portion of which a sleeve is fitted, with a spool valve slidably fitted into the sleeve. The spool valve has a rear end which abuts against the bottom of a bottomed opening formed in an input shaft. The invention allows a misalignment between the axes of the primary piston and the input shaft.

Abstract: In a braking pressure intensifying master cylinder of the present invention, as an input shaft 53 travels forwards in a braking maneuver, a control valve 54 is actuated to develop fluid pressure according to the input in a reaction chamber 38 and a pressurized chamber 35. A stepped spool 45 as a part of the control valve 54 travels such that force produced by the fluid pressure and spring force of a spring 51 are balanced, whereby the stepped spool 45 can function as a travel simulator. By changing the pressure receiving areas of the stepped spool 45 and/or changing the spring force of the spring 51, the travel characteristic of the input shaft 53 as the input side can be freely changed independently from the output side, without influence on MCY pressure as the output side of the braking pressure intensifying MCY 1. In addition, the master cylinder pressure can be intensified when necessary with a simple structure.

Abstract: A master cylinder which includes a primary piston and a thrust piston disposed within a housing, and defines an intensifying chamber at a location rearward of the thrust piston. An input shaft has a front end which is disposed within the intensifying chamber. The thrust piston is formed with a communication path (discharge passage), and a control valve is disposed between the thrust piston and the front end of the input shaft to open or close the communication path (discharge passage). When the input shaft is driven forward under the inoperative condition shown and the pump is operated to introduce a discharge pressure from the pump into the intensifying chamber, a liquid pressure is generated in the intensifying chamber and drives the primary piston forward, generating a liquid pressure in a liquid pressure chamber. In this manner, a master cylinder can be provided which has a simple and inexpensive construction with a reduced number of parts and which is compact in size.

Abstract: A booster 3 has a structure that a return valve 14 is formed into a two-step throttle incorporating a first throttle valve 36 and a second throttle valve 37 formed continuously from the first throttle valve 36. When a valve spool 28 has been moved forwards when the operation is performed, a gap of the first throttle valve 36 is reduced. Also a gap of the second throttle valve 37 is reduced. Therefore, hydraulic fluid discharged from a pump is passed through an inlet passage 12, and then introduced into the second annular groove 13. Then, the hydraulic fluid is throttled by the first throttle valve 36, and then throttled by the second throttle valve 37. That is, the hydraulic fluid is throttled in the two-step throttling manner. As a result of the two-step throttling structure, the overall velocity of the flow of the hydraulic fluid can smoothly be changed without rapid change. Therefore, fluid flow noise caused from the change in the velocity of the flow can be prevented.

Abstract: A brake system for use in connection with a vehicle including a hydraulic internally boosted master cylinder, a hydraulic pump, and hydraulic brakes wherein the master cylinder controls hydraulic fluid pressure to the brakes and has a primary or sensing piston, a modulator stem, and a secondary pistons, with the sensing piston responsive to a mechanical input force to urge the secondary piston forwards increasing the hydraulic fluid pressure applied to the brakes. In a second embodiment, the internally boosted master cylinder further includes a tertiary piston movable by hydraulic pressure between retracted and extended positions and biased toward the retracted position by a tertiary piston return spring. The tertiary piston controls hydraulic pressure applied to one or more brakes independent of the brakes controlled by the secondary piston.

Abstract: The invention relates to a hydraulic pressure booster which can be used to perform servo control of input and output at the preset servo ratio in, for example, a brake booster. In particular, the invention relates to a hydraulic pressure booster, which is designed to reduce the loss stroke of an input shaft in the initial stage of operation. This can be achieved by providing a stopper which directly abuts the input shaft when it is non-operational and which maintains the input shaft at the preset advance position separated from the detent in relation to the power piston.

Abstract: In a brake system (10) having a fluid pressure servomotor (12) with a housing having an operational chamber (30) connected to an intake manifold (102) of a vehicle and a control chamber (32) connected to an accumulator (50). A wall (28) which separates the operational chamber (30) from the control chamber (32) carries a valve (38) connected to receive an input from an operator by way of pedal (20). In the rest position, the valve (38) allows the vacuum created at the intake manifold (102) to evacuate air from the operational chamber (30) and control chamber (32). When an operator desires to effect a brake application, an input force applied to the valve (38) by way of pedal (20) allows air from the accumulator (50) to be communicated to the control chamber (32) and create a pressure differential across the wall (28).

Abstract: A hydraulic booster has a boost piston (19) which receives the thrust of boost pressure generated in a boost chamber (15) to move the boost piston for urging a master piston (12) of a master cylinder in a brake applying direction. An input member (17) is relatively movably with respect to the boost piston (19). A pressure regulating device has an input directional control valve (22, 45) for allowing or cutting off communication between the boost chamber (15) and an auxiliary power source (14). An output directional control valve (24, 46) establishes or cuts off communication between the boost chamber (15) and a reserve tank (9). The boost piston (19), the input member (17) and the pressure regulating device are arranged inside a housing (1). An input member positioning device brings the rear end of the input member (17) into contact with a stop member (51) which is anchored to the housing (1), when a pedal force is zero for stopping a rearward movement of the input member.

Abstract: A pair of spaced apart large-diameter and small-diameter lands between which a fluid chamber is defined are formed on a second piston in a tandem cylinder to which an anti-skid device is added. Booster pressure is applied to the fluid chamber to act on the large-diameter land in a manner fluidly locking the second piston against movement despite a reduction in pressure in the first and second pressure chambers during operation of the anti-skid device. As a result, the movement of the brake pedal in the normal direction of depression is prevented when the anti-skid devices operates.

Abstract: A hydraulic booster including a power piston, a booster chamber for applying a boost pressure to the power piston, an input rod, an intermediate inlet chamber for introducing a power source pressure thereinto, a valve mechanism provided in a valve chamber of the power piston and a differential pressure regulating valve subjected to a valve opening pressure equal to a sum of a spring pressure and a pressure of the boost chamber and a valve closing pressure equal to a pressure of the intermediate inlet chamber so as to control opening and closing of a communicating path for introducing the power source pressure into the intermediate inlet chamber such that pressure of the intermediate chamber is kept higher than the pressure of the boost chamber by a predetermined value at all times.

Abstract: A hydraulic brake system for automotive vehicles has a master brake cylinder connected to an unpressurized reservoir and a brake line connected to a working chamber of the master brake cylinder and leading to pressure control valves of a brake slip control device. The pressure control valves are followed by wheel brake cylinders. The working chamber of the master brake cylinder is connectible to a pressure medium source upon the starting of the brake slip control device. The outlet pressure of the pressure medium source lies above the maximum braking pressure achievable by applying the master brake cylinder. The working chamber's front side (away from the first master cylinder piston) is sealed by a second master cylinder piston sealedly arranged within the master cylinder. The second master cylinder piston is sealed relative to the master cylinder by a non-return valve gasket.

Abstract: A braking pressure generator consists of a hydraulic brake booster (2) actuatable by a brake pedal (16) and of a master brake cylinder (1) whose master cylinder piston (19) is actuatable by a booster piston (14) pressurizable with an auxiliary hydraulic pressure. The booster piston (14) is guided sealedly and axially displaceably in the bore of an annular secondary cylinder piston (41) which, with a front face (52), confines the booster chamber (13) and which, with its stepped surface area (51), confines a secondary cylinder chamber (44) communicating with a pressure chamber (22) of the master brake cylinder (1) via a pressure line (46). In the brake actuating direction, the secondary cylinder piston (41) is supported at a stop ring (48) of a connecting rod (20) between the booster piston (14) and the master cylinder piston (19).

Abstract: A hydraulic multiple-circuit brake system is proposed, the brake amplifier of which has a multiple-chambered refill container. With an intake connection of its pump, an energy supply apparatus comprising a pump and a reservoir is connected at a predetermined fill level (h/2) to the refill chamber which is intended for the supply of an open brake circuit (II). In this manner, it is attained that if there is an energy failure, the open brake circuit will be capable, as a closed brake circuit, of continuing to function.

Abstract: The hydraulic brake booster (12) includes a resilient member (96) disposed between an input member (94, 194, 294) and a pair of valve members (98, 101; 112) which control fluid pressure flow from an accumulator (14). When the input member (94, 194, 294) is actuated by the vehicle operator, theresilient member (96) is compressed so that the input member (94, 194, 294) moves relative to the valve members (98, 101; 112) and thus provides for greater movement of the input member (94, 194, 294) than for the valve members (98, 101; 112). The booster (12) includes a hydraulic or mechanical lockout which, in the absence of fluid pressure from the accumulator (14), eliminates the movement of the input member (94, 194, 294) relative to the valve members (98, 101; 112) so that the relative movement eliminated is not added to the valve stroke during manual operation of the booster (12).

Abstract: The brake booster (12) includes a housing (30) with at least one piston (38) disposed in a bore (32) to separate a pressure chamber (42) from a work chamber (76). The piston (38) abuts a valve housing (79) containing therein a valve assembly (80) and the valve assembly (80) is connected to an input assembly (72) abutting the other end of the valve housing (79). The piston (38) and valve housing (79) are joined by connector (73) which permits limited movement of the piston (38) relative to the valve housing (79) before coupling the piston (38) and valve housing (79) together for joint movement.

Abstract: A hydraulic booster including an input piston adapted to be actuated by a manually operated member such as a brake pedal. The input piston is axially slidable in a power piston which is in turn axially slidable in a booster casing. The power piston divides the inside cavity of the casing into a power chamber and a reservoir chamber. An electrically operated plunger pump is provided and has an outlet port connected with the power chamber and an inlet port. Between the input piston and the power piston, there are defined a first valve and a second valve. The first valve functions to open the power chamber to the reservoir chamber when the pedal is released but to disconnect the power chamber from the reservoir chamber when the input piston is depressed by a first predetermined distance.

Abstract: A hydraulic dual-circuit tandem master brake cylinder intended for use in brake systems of motor vehicles is proposed, to which a closed brake circuit (I) and an open brake circuit (II), the latter reinforced by auxiliary pressure, are connected. In order to switch the control valve, the main brake cylinder has a foot-actuated push rod as an actuation member, with transmission of force via a control contour or a travel-limiting spring, and it furthermore has an auxiliary piston member near the pedal, this member having an effective surface for making the feedback of the brake pressure which has been established perceptible. In this manner, a small, compact master brake cylinder construction which is very favorable in price is created. It is furthermore of advantage that the pedal characteristic is designed optimally in terms of human engineering. The main cylinder can also be used at little expense for an anti-wheel-lock apparatus as well.

Abstract: A power valve for a vehicle braking system includes a main pressure chamber (4) defined between the body (1) and spool (2) and connected to the outlet (5), the spool being displaceable under an input effort to close communication between the chamber (4) and a reservoir port (8) and open communication of the chamber (4) with an inlet (7), and an auxiliary chamber (10) to which fluid pressure may be supplied through a port (11) to exert a force on the spool for reducing the pressure supplied to the outlet (5) for a given input effort applied to the spool (2).

Abstract: A hydraulic dual-circuit brake booster in which two brake circuits are closed brake circuits. A dual-circuit tandem main cylinder is used in combination with a pedal push rod supported in a displaceable piston and exposed to the brake pressure directed into the system by the control valve. The pedal push rod and the tandem main brake cylinder are disposed coaxially and the brake booster is particularly suitable for use with anti-skid brake systems.

Abstract: An arrangement for controlling the supply of pressurized hydraulic fluid from a master cylinder and from a pressure source into hydraulic circuits leading to wheel brake actuating cylinders includes a valve device including a control piston acted upon by a spring-loaded auxiliary piston in one direction and by the pressure in a return conduit in the opposite direction. Upon brake pedal depression, hydraulic fluid pressure from the pressure source acts on the auxiliary piston in opposition to the spring force so that the auxiliary piston ceases to act on the control piston. Then, as hydraulic fluid is discharged from the brake actuating cylinders during antiskid control action, pressure builds up in the return conduit and propagates to the control piston to move the same into its open position in which it admits pressurized fluid from the pressure source to check valves which are acted upon in opposition to their opening by the tandem master cylinder pressures.

Abstract: A braking-force booster which contains a pressure source, a pedal operated control valve and at least one main brake cylinder; a piston which creates the brake pressure, is exposed to the pressure created in the main brake cylinder by means of the control valve, wherein the control valve, dependent on the pedal displacement, interrupts a connecting channel between the main brake cylinder and a pressureless connection and temporarily creates a second connecting channel between the pressure source and the main brake cylinder. The pedal operated control valve contains a plunger movable by the pedal which extend into the main brake cylinder, and the first connecting channel is integrated into the main brake cylinder piston. The first plunger has a valve closing member for shutting off this connecting channel during the corresponding approach.

Abstract: A dual power brake booster assembly in which the hydraulic boost section is initially operated, the vacuum booster section is then operated to runout while the hydraulic section maintains a hydraulic boosted force level, the hydraulic section is then further operated to further increase the hydraulic boosted force as the vacuum booster section maintains the vacuum boosted force level attained by it at runout, and additional master cylinder actuation by additional manual force. The invention also includes the method of generating brake actuating pressure. The brake booster assembly may be operated only to the extent necessary to produce the desired amount of master cylinder actuation. The booster assembly will operate when the power source for one section is diminished or not available. It is also operable manually when pressure from neither power source is available.

Abstract: An hydraulic booster has a housing provided with an input member, a boost piston, an output member, and connections to a source of pressure and a fluid reservoir. A force applied to the input member is transmitted to the output member and augmented by the boost piston in response to pressurization of a boost chamber controlled by a valve mechanism in response to operation of the input member. An auxiliary chamber is defined between the boost piston and the output member. In a first stage of operation to take up lost-motion in the system, the auxiliary chamber is supplied with fluid from the source to advance the output member relative to the boost piston through a distance determined by a limiting mechanism. In a second stage of operation the output member and the boost piston move together in response to pressurization of the boost chamber. The area of the boost piston on which the auxiliary pressure acts is greater than or equal to the effective area of the boost piston.

Abstract: In an hydraulic booster for a vehicle braking system a boost piston provides an output force in response to pressurization of a boost chamber under the control of a boost valve mechanism, which controls communication between the boost chamber and a pressure source and the boost chamber and a fluid reservoir. The operation of the boost valve mechanism is controlled by pressure in a control chamber which is pressurized by operation of a pedal-operated input piston. A recuperation valve controls communication between the boost and control chambers, and is operated in response to movement of the input piston. Pressure in the boost chamber acts on the input piston to urge it in a direction to keep the recuperation valve closed. This enables the input piston to work in a bore in the boost piston, with the control chamber in the boost piston and forward of the boost chamber.

Abstract: A brake booster is provided with a housing (30) having a bore (32) therein receiving a piston (52) carrying a valve assembly (68). An end plug (50) cooperates with the piston (52) to form a work chamber (66) and an input member (84) extends through the end plug to cooperate with the valve assembly (68). In the rest position, the work chamber (66) communicates with a reservoir (38) via passage 112, auxiliary chamber 104, passage 116, bore 32 and passage (40) independently of the piston (52).

Abstract: A power fluid system for a vehicle embodying a two-fluid pump which utilizes an existing source of fluid under pressure is provided. The existing source of fluid enables a second source of fluid under pressure to be established through the two-fluid pump. Vehicles often require high pressure fluid to operate auxiliary equipment such as traction or anti-skid units, limited-slip differentials, and hydraulic load-leveling systems. More specifically, the two-fluid pump is a linear pump operated by fluid under pressure from the power steering pump of the vehicle. The two-fluid pump can supply a different fluid under higher pressure for the auxiliary equipment, as required. The pump is pulse cycled quickly to provide adequate quantities of both sources of fluids with the use of small capacity accumulators.

Abstract: A hydraulic brake booster which has an input valve control member acting through a controlled rate spring and through a lever pivoted on the booster housing in the power chamber to move a spool valve in a bore parallel to the power piston so that the input is strictly through the spring. The lever has no connection to the power piston. The control valve is hydraulically unbalanced to a release position and is also urged to the release position by a valve spring. This maintains a proportion between the input force due to the reaction spring, through which input force is applied, and booster pressure. Upon power runout or failure the input and reaction piston overtravels and contacts the output rod to move that rod without moving the power piston.

Abstract: An air/hydraulic servomotor unit for providing power assistance for a clutch hydraulic operating system and comprising a compressed air cylinder, a hydraulic slave cylinder, a load proportioning means that determines what ratio of the unit output is derived from the hydraulic and air cylinders, and a clutch operating member.The hydraulic slave cylinder is secured to one end of the air cylinder housing and has a piston which passes through the air cylinder piston so that both pistons can act against the proportioning means. All the unit output loads pass through the proportioning means prior to being transmitted to the operating member.

Abstract: A motor vehicle provided with servo-assisted controls for the brakes and steering, has an hydraulic system of the type comprising a volumetric pump the input of which is connected to a reservoir, and first and second distributor devices the first of which is associated with the steering control device and the second of which is associated with the master cylinder for control of the brakes. The said second distributor device is formed in such a way as to function also as a pressure modulating valve.

Abstract: A hydraulic brake booster (10) includes a spring-balanced control valve (42) communicating pressurized fluid to a pressure chamber (14) in response to an operator input. The magnitude of the fluid pressure communicated to the pressure chamber (14) is a function of the balance of spring forces applied to the control valve (42) by a pair of opposed springs (50, 82). An adjustable assembly (92) engages one of the opposed springs (50, 82) so that the balance of spring forces applied to the control valve (42) may be adjusted to limit to a safe level the maximum fluid pressure communicable to the pressure chamber (14). The adjustable assembly (92) includes a pair of relatively-rotatable members (106, 108) which each define oblique cam surfaces (122, 124) engaging the other member. One of the members (106) engages one of the opposed springs (50, 82). The other member (108) includes an elongate stem (118) terminating in an end (120) external of the booster housing (12).

Abstract: A hydraulic control system for a brake device comprises independent first and second brake circuits, the first circuit communicating with a first chamber pressurized by movement of a master piston actuated by a brake pedal, and the second circuit communicating with a second chamber whose pressure is dependent on that of the first and is developed by an assistance circuit, the second chamber being separated from the assistance circuit by a piston.

Abstract: A brake valve is disclosed, which is provided with an enlarged chamber, at one end of which is slidably disposed an annular piston. A reaction piston is carried on a valve rod; the reaction piston radially extends so as to cover the annular piston. When the reaction piston moves toward the annular piston, flow of fluid through the valve is restricted and then halted. Mating beveled conical surfaces are provided on the annular piston and the reaction piston to provide a mutual centering and seating action as the reaction piston is moved toward the annular piston. Belleville washer elements are stacked in opposed array on the valve rod for resiliently urging the reaction piston into engagement with the annular piston, and for inhibiting mechanical shocks from being transmitted from the valve rod to the reaction piston, and vice versa. Conical fluid flow stop members regulate the flow of fluid from the valve chamber to downstream brake elements.

Abstract: A device for the power-assisted control of a hydraulic transmitter is disclosed which includes a transmitter cylinder having a first and second bore provided therein, a main piston with a bore hole, disposed in the cylinder, valve means disposed in the bore of the cylinder, a fluid source communicated with the cylinder, a control piston movably disposed in the second bore and having a control section and a second section formed thereon wherein the control section of the control piston is larger than the second section of the control piston.

Abstract: A hydraulic brake booster having a mechanical ratio changing mechanism between the booster input rod and one of the booster valve control members. The mechanism includes reaction levers pivotally mounted on the input valve control member and on a support member so that in normal booster operation the levers operate to move the input valve control member at a faster rate than the input rod, while the levers pivot to permit direct mechanical transmission of force from the input rod through the booster when no power or insufficient power is available to operate the booster.

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: A brake booster includes a housing with an inner wall defining a pair of pressure chambers. A passage in the inner wall communicates the pressure chambers with each other and an input member is slidably disposed in one of the pressure chambers and an output member is slidably disposed in the other pressure chamber. A resilient member extends between the inner wall and the input member and substantially defines a variable orifice to control fluid communication between an inlet and a return. The return is disposed within the inner wall and the resilient member comprises a coil spring which permits fluid communication between the coils. When the input member is moved the coil spring is contracted to decrease the spacing between the coils, thereby restricting fluid communication between the inlet and the return. Consequently, increased fluid pressure within the other chamber urges the output member to move thereby actuating braking.

Abstract: A vehicle brake booster and master cylinder assembly has a vacuum suspended booster section which is controlled by movement of the vehicle brake pedal. A hydraulic booster section is in series with the vacuum suspended booster section, and a master cylinder unit is in series with the hydraulic booster section. The assembly is so arranged that in normal operation the vehicle operator obtains boosted brake actuating pressures by operation of the vacuum suspended booster which acts through the hydraulic booster mechanism without operating the hydraulic booster. When greater brake actuating pressures are required, as indicated by increased brake pedal force exerted by the operator, the vacuum booster reaches its limit or runout condition and the hydraulic booster is operated so as to continue the increase in master cylinder output pressure.