Abstract: A pneumatic brake booster having a vacuum chamber and a working chamber in a booster housing separated from one another by an elastic diaphragm. The diaphragm bears in regions against a diaphragm plate axially displaceable between a zero position and a maximum stroke. An axial spacing between the zero position and the maximum stroke defines a stroke range of the brake booster. The diaphragm has a rolling fold which, during the displacement of the diaphragm plate, rolls on a rolling region on an inner wall of the booster housing. In order to offer a solution in which it is the intention for a modular system for different stroke ranges to be formed more efficiently and for the efficiency loss to be minimized or avoided, the booster housing has, in the rolling region, a tapered, conical portion with a cone angle ?8° and an axial extent >?*stroke range.

Abstract: A brake device and an automatic driving vehicle using the same are provided. The brake device includes an electrically controlled brake assembly, a mechanically controlled brake assembly and a shaft. The electrically controlled brake assembly has a main body and a brake control link. The shaft is connected between the electrically controlled brake assembly and the mechanically controlled brake assembly. The mechanically controlled brake assembly includes a pedal, an elbow, a brake link group and a brake pump. The first end is connected to the pedal, and the fulcrum is between the first end and the second end and is located close to the second end. The brake link group is connected between the elbow and the brake control link. The brake pump has an adjustable rod, and one link of the brake link group is connected to the adjustable rod.

Abstract: A bicycle control device is basically provided with a bracket, a shift unit, a hydraulic cylinder unit and a first operating member. The bracket includes a coupling portion that is configured to be coupled to a handlebar. The shift unit is mounted to the bracket. The hydraulic cylinder unit is mounted to the bracket in a location that is closer to the coupling portion than the shift unit. The first operating member is pivotally mounted relative to the bracket around a first pivot axis to operate the hydraulic cylinder unit. The first pivot axis is disposed between the shift unit and the coupling portion.

Abstract: A brake apparatus is provided which has applicability to a wide range of vehicles. The brake apparatus includes a master cylinder provided in such a manner that a piston is axially operable in a master cylinder housing, and a stroke simulator including a reaction force piston axially operable by brake fluid introduced into a stroke simulator housing. The master cylinder housing is fixed to the stroke simulator housing. The stroke simulator housing is positioned between the master cylinder housing and a fixation piece structured to fix the stroke simulator housing to the vehicle. The fixation piece is spaced from the master cylinder housing.

Abstract: A brake booster for use in a hydraulic braking system having a brake pedal, a master cylinder, and a hydraulic control unit includes a housing, a screw drive arrangement positioned at least partially in the housing, a motor coupled to the housing for actuating the screw drive arrangement, and a piston assembly positioned in the housing. The piston assembly and the housing together at least partially define a first fluid chamber having an opening for providing fluid communication with the master cylinder, and a second fluid chamber having an opening for providing fluid communication with the hydraulic control unit. The screw drive arrangement is movable relative to a piston of the piston assembly between an engaged position, in which the first fluid chamber is isolated from the second fluid chamber, and a disengaged position in which the first fluid chamber is not isolated from the second fluid chamber.

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 for a vehicle includes an active booster master cylinder connected with the wheel cylinders, and a controller for operating active booster master cylinder during braking. The primary master cylinder, which is located remotely from the active booster master cylinder, is selectably connected with either a pedal feel emulator or a servo system which applies the brakes using the active booster master cylinder and a hydraulic output from the primary master cylinder in the event that control of the active booster master cylinder becomes impaired.

Abstract: A normally closed secondary solenoid opening/closing valve 36 is provided along a secondary branched fluid pipe 35 establishing a communication between an accumulator 11 and a reservoir 8 through a fluid pressure input side to a fluid pressure output side of a regulator valve 3, and in the event that a fluid pressure supplied to the regulator valve 3 decreases down to or lower than a predetermined range due to something abnormal occurring in the accumulator 11, the state of the secondary solenoid opening/closing valve 36 is changed over from a closed state to an opened state, whereby a residual pressure in the accumulator 11 and a residual pressure in the output fluid pressure chamber 15 can be released through the reservoir 8 which is in communication therewith through an output fluid pipe 31 and the secondary branched fluid pipe 35 along which the secondary opening/closing valve 36 is provided.

Abstract: An oil pressure generator for a vehicle is disclosed, including a bar-shaped steering handle having a pipe structure, a lever pivotally mounted in the vicinity of an end portion of the handle, and a master cylinder for a hydraulic brake or a hydraulic clutch, the master cylinder being configured to house a piston movable according to an operation of the lever, wherein the master cylinder is located within the handle.

Abstract: A hydraulic braking pressure generating apparatus for a vehicle includes a hydraulic pressure generator for generating a predetermined hydraulic pressure irrespective of a braking operation of a brake operation member and for outputting the predetermined hydraulic pressure, an input member moved in response to the brake operation member, a first elastic member for transmitting a brake operation force applied to the input member and for applying a stroke corresponding to the brake operation force to the input member, a regulation valve connecting to the first elastic member and for regulating the outputted hydraulic pressure of the hydraulic pressure generator in response to the brake operation force transmitted through the first elastic member and for outputting a regulated hydraulic pressure and a second elastic member connecting the regulation valve and for urging the regulation valve toward its initial position.

Abstract: A hydraulic brake apparatus is provided with a master cylinder, an assisting device for assisting the master piston to be advanced in response to operation of a brake pedal, and an auxiliary piston having a large diameter portion and a small diameter portion to define first and second pressure transmitting chambers, with the large diameter portion connected to the assisting device. A first valve member is provided for controlling the communication between the first and second pressure transmitting chambers, and a second valve member is provided for controlling a flow of the brake fluid from the first chamber to the second chamber. A valve opening mechanism is provided for opening the first valve member, and mechanically connecting the second valve member with the first valve member, to open the second valve member when the auxiliary piston is retracted from its advanced state to its initial position.

Abstract: A pressure-responsive type pressure holding valve is proposed which serves to hold the hydraulic pressure in a circuit connected to a spool valve. A piston valve biased by a spring is mounted in a housing formed with a valve chamber, a small-diameter bore and a large-diameter bore. The outer periphery of the small-diameter portion of the piston valve is sealed by a seal member. A first port opened and closed by a valve head at the tip of the piston valve is connected to a circuit that needs pressure holding, a second port to a circuit in which minute leak can occur, and a third port to a source of hydraulic pressure for opening the valve.

Abstract: A hydraulic brake device for a vehicle includes an auxiliary piston having an effective cross-sectional area larger than that of a master piston, and a pressure transmitting chamber provided between the large diameter portion and the master piston. The auxiliary piston is operatively associated with the assisting operation of an assisting device. A valve mechanism hydraulically closes the pressure transmitting chamber when the actuation of the master piston is assisted by the assisting device through the auxiliary piston and establishes hydraulic communication between the pressure transmitting chamber and a reservoir of the master cylinder when the master piston is not actuated by the assisting device.

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 hydraulic brake device for a vehicle includes a master cylinder having a master piston and an auxiliary piston for assisting the actuation of the master piston. The vehicle hydraulic brake device also includes a first valve mechanism for hydraulically closing a first pressure transmitting chamber when the actuation of the master piston is assisted by an assisting device, a second valve mechanism for hydraulically closing a second pressure transmitting chamber after the pressure in the first pressure transmitting chamber reaches a predetermined value, and for hydraulically connecting the second pressure transmitting chamber with the first pressure transmitting chamber when the master piston is not actuated by the assisting device.

Abstract: In a braking pressure intensifying master cylinder, 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 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 a master cylinder pressure as the output side of the braking pressure intensifying a master cylinder (1). In addition, the master cylinder pressure can be intensified when necessary with a simple structure.

Abstract: A fully hydraulic brake power generator/master cylinder unit (10) for a vehicle brake system has a housing (12) with a bore (14) which is formed therein and in which a primary piston (16) is arranged sealingly and displaceably. Located in the bore (14) is a first pressure chamber (22), one boundary wall of which is formed by one end wall (20) of the primary piston (16). In order to actuate the unit (10), there is an input member (60) which is displaced during actuation. A hydraulic booster stage (38), which has a booster chamber (44) with an inlet for hydraulic fluid under pressure, acts on the primary piston (16). In order to improve the simulation of brake pressure feedback via the input member (60), a spring arrangement (70) is provided, with a first spring (72) and a second spring (74) which are connected in series. The spring force of the second spring (74) is detectably greater than the spring force of the first spring (72).

Abstract: A vehicle brake control valve includes a piston assembly which is movable a stepped cylindrical bore of a valve housing in response to an actuating force against the force of a spring. The piston assembly includes port control edges which control communication between a brake pressure chamber which can be connected to the vehicle brakes, a reservoir, and a pump. Both the pump and the actuating force contribute to the brake pressure which builds up in the brake pressure chamber. The piston assembly includes an actuator piston and an annular piston that sealingly slides within a larger portion of the stepped bore. After the actuator piston moves a pre-set distance (H) it carries with it the annular piston. The annular piston, the actuator piston and a wall of the larger diameter portion of the stepped bore enclose a fill pressure chamber which is separated from the brake pressure chamber to achieve two-stage pressure build-up during manual braking (emergency braking) when the pump is inoperative.

Abstract: In a hydraulic boosting device of the present invention, when the pressure stored in an emergency accumulator is less than a set pressure, a stepped piston 70 moves downward, a throttle valve 72 is set in a first position where the throttle valve 72 is seated in a valve seat 71, and hydraulic fluid flowing from a pump through an inlet path 14 is restricted by a flow limiting valve 68 so as to develop a fluid pressure in an annular path 73. The fluid pressure is stored in the emergency accumulator through a path 69, an accumulator valve 27, and an accumulator path 31. When the pressure stored in the emergency accumulator exceeds the set pressure, the stepped piston 70 moves upward, the throttle valve 72 is set in a second position where the throttle valve 72 is apart from the valve seat 71, and the hydraulic fluid from the pump is not restricted by the flow limiting valve 68 at all so as to flow freely toward a control valve. In this state, no fluid pressure is developed in the annular path 73.

Abstract: A braking unit includes an intensifier mechanism for intensifying a braking liquid pressure of a master cylinder upon failure of a liquid pressure booster. The braking unit comprises the intensifier mechanism for intensifying the braking liquid pressure of the master cylinder when actuated, and a control valve which makes the intensifier mechanism operable upon failure of the liquid pressure booster. The control valve comprises a valve member which is urged by a spring tensioned with a given load and which is urged in the opposite direction from the spring by a liquid pressure of a power chamber of the liquid pressure booster. The valve member makes the intensifier mechanism operable whenever the resilience of the spring exceeds the urging force produced by the liquid pressure in the power chamber of the liquid pressure booster. This prevents an operational lag of the intensifier mechanism in the event the liquid pressure booster fails.

Abstract: A travel simulator having a progressive pedal characteristic to be in operation in a power-actuated service brake. The hydraulic brake system has a valve assembly for the switching of the brake system into operation as either a service brake or as an emergency brake. The master cylinder has a pressure fluid reservoir, two pressure chambers, and an intermediate piston as well. The intermediate piston is supported on a travel simulator spring. When the service brake is in operation, pressure fluid can be diverted from the second pressure chamber into the reservoir, and the intermediate piston is moved against the resistance of the spring. When the emergency brake is in operation, both pressure chambers communicate with one another so that the intermediate piston is pressure balanced. When the pedal is actuated, pressure fluid is expelled from the first pressure chamber. The intermediate piston is not subject to any motion during an emergency brake operation. The brake system is for use in road vehicles.

Abstract: A fluid pressure type booster device is capable of feeding an output pressure of a fluid pressure source in a controlled manner by permitting a slide member to slide so as to balance the force acting in an advancing direction by a fluid pressure of a pressure chamber in accordance with an operation of an operating member and the reaction force of a reaction chamber. The device includes an input piston slidably fitted in a housing to define the pressure chamber between the input piston and an interlocking member, a spring mounted in a compressed manner between the input piston and the interlocking member, and an on-off valve interposed between the pressure chamber and the fluid tank so as to be closed in accordance with an advancing movement of the input piston with respect to the interlocking member by an amount not less than a predetermined value.

Abstract: An actuating unit for hydraulic automotive vehicle brake systems, including a vacuum brake power booster, a master brake cylinder, and an operating element, configured to achieve a reduction of overall axial length and a simultaneous reduction of the weight and a relief of the booster housing from forces of reaction. The brake pedal (3) operating arm is interposed between the vacuum brake power booster (1) and the master brake cylinder engaging an axially extending member interconnecting a control valve piston and a master cylinder piston (2). The booster housing (10) and fluid reservoir (4) are mounted within the engine compartment while the master cylinder housing has a flange portion fixed to the splashwall and a main portion which projects out of the engine compartment through the splash wall, and into the passenger compartment. The hydraulic reaction forces are absorbed directly from the master cylinder housing into the splashwall rather than through the booster housing.

Abstract: A fluid pressure booster device includes a booster body, a control piston in the booster body for forward and rearward movements to define a boosting chamber between the control piston and a rear surface of a master piston of a master cylinder, a valve piston in the control piston for forward and rearward movements and communicating at its front face with the boosting chamber, a reaction piston in the control piston for forward and rearward movements and connected to an operating member, the reaction piston defining a reaction chamber between itself and a rear face of the valve piston, a stroke accumulator having an accumulation chamber connected to the reaction chamber, an inlet valve disposed between the control piston and the valve piston and interposed in a flow passage extending between the boosting chamber and a fluid pressure source, the inlet valve being closed when the valve piston is retracted and opening when the valve piston advances, and an outlet valve disposed between the control piston and the

Abstract: The hydraulic brake booster (12) of the present invention comprises a full power hydraulic brake booster (12) that provides false travel during full power operation and improved pedal feel during manual operation. The booster (10) has a housing (24) with a slidable sleeve assembly (60) therein, the assembly (60) housing a sleeve member (98) which is displaced by accumulator fluid pressure against a collet housing (78) and a moveable collet member (79) located about an input member (94). The sleeve member (98) displaces the moveable collet member (79) against a resilient member (77) when the sleeve member (98) is displaced by hydraulic fluid pressure from the accumulator (14).

Abstract: The invention provides a brake booster including in a preferred embodiment a housing, first and second annular flexible diaphragms spaced from one another forming a sealed second chamber within the housing and a sealed first chamber between the first diaphragm and the first end of the housing, a generally annular shaped power piston for connection with the master cylinder piston, a chamber valve seat separating the first and second chambers, an inlet valve slidably mounted within the power piston, and a control valve spring biased away from the power piston and connected with the pedal linkage and being slidably and sealably mounted within first end of the housing.

Abstract: In a brake apparatus for a hydraulic two-circuit brake installation of a road vehicle with static brake circuits, an outlet pressure space is provided for one of these brake circuits in which the brake pressure that is coupled into a static brake circuit of the vehicle, is adapted to be built up by the displacement in the same direction of a master cylinder piston which is also displaceable by the pedal force alone, and of a servo piston which is displaceable only when the brake force servo unit is intact.

Abstract: A hydraulic booster for a master cylinder in which an inlet valve is interposed between an output pressure chamber at the back of the booster piston and an input pressure chamber connected to a pressure source. Advance of the valve piston opens the inlet valve. An outlet valve between the output chamber and an outlet chamber connected to an oil tank closes at advance of the valve piston relative to the booster piston. The booster chamber is exposed to a rear of a master cylinder operation piston. The valve piston oil feed passage connects input pressure chamber with booster chamber at opening of the outlet valve. The reaction chamber at the front surface of the booster piston is reduced in volume with the advancing movement and is connected to an accumulator making it possible to smooth initial operation of the master cylinder and reduce booster system size.

Abstract: In a booster casing (12) a movable wall (14) separates two compartments (16,18) from each other. In inoperative position, a control valve (20) connects the two compartments (16,18) with each other, and separates them when in an operative position, connecting one (16) of them to a source of pressure which differs from the pressure in the other compartment (18). A cylinder casing (52) is attached to the booster casing (12), projects into the same, and contains at least one pressure piston (54) which defines a pressure chamber (56) for pressurizing a brake circuit. An input piston (40) having a greater effective surface than the pressure piston (54) and defining an input chamber (42) is movable together with the movable wall (14). The input chamber (42) is adapted to be relieved of pressure by a relief valve (80) if the booster (10) fails. The input piston (40) and chamber (42) are arranged inside the booster casing (12), and the input piston (40) forms part of the movable wall (14).

Abstract: A brake actuating device for automotive vehicles comprises a hydraulic brake force booster and a hydraulic tandem master cylinder to which pressure is applied by the brake force booster and which is in communication with the hydraulic wheel brake circuits. The hydraulic piston of the brake force booster applies pressure to the primary master piston of the said hydraulic tandem master cylinder. Pressure is applied to the hydraulic piston of the hydraulic brake force booster from a hydraulic pressure source through a normally closed opening valve which, through a function electronic unit receiving by way of a control input in the form of a guide quantity, an input signal representative of the pedal travel is alternately opened and closed. Accordingly the hydraulic brake pressure build-up is effected in accordance with a predetermined function stored in the function electronic unit between pedal travel and brake pressure with no lost motion of the brake pedal.

Abstract: A brake system having anti-skid control for motor vehicles has a brake booster having a brake valve and an emergency brake piston, and a master brake cylinder, combined in one housing with the brake booster having a master brake piston and two separate brake chambers, which supply brake fluid to one dynamic brake circuit and one static brake circuit (II and I), respectively. If the pressure fails, the master brake piston is mechanically actuated via the emergency brake piston. To attain a simple structure with a feedback-free brake pedal during anti-skid control, the emergency brake piston and the master brake piston are accommodated in a continuous housing bore such that the emergency brake piston forms the second defining wall for the first brake chamber, and the master brake piston rests with force on the emergency brake piston. A device for restoring the emergency brake piston upon the onset of the anti-skid control assure free mobility of the master brake piston.

Abstract: A brake unit having a hydraulic brake booster and twin master cylinders in a common housing. The brake booster comprises a drive cylinder between the master cylinders which can be subjected to the outlet pressure of a brake valve of the brake booster which supplies an outlet pressure proportional to the pedal travel. A compensating cylinder, which jointly executes the strokes of the drive-cylinder piston and can likewise be subjected to the outlet pressure of the brake valve transmits the actuating forces generated by the drive cylinder to the pistons of the master cylinders via a rocker articulated pivotably on the compensating piston. The effective piston surface of the compensating cylinder is somewhat larger than that of the drive piston.

Abstract: A brake booster has a first booster cylinder and a booster piston disposed in it for displacing a master cylinder piston to pressurize a brake circuit. A tappet displaces the first booster piston directly if boost fluid pressure is inadequate. A second booster piston in a parallel booster cylinder drives a pump piston which also pressurizes the brake circuit. The second booster piston and the pump piston have hydraulically effective surface areas which are matched to one another so as to have a larger boosting ratio than the first booster piston and master cylinder piston. Forward displacement of the second booster piston causes a bent arm to contact and push the first booster piston forward. If the boost pressure supply apparatus fails, then only the first booster piston and the master cylinder piston are displaced by the brake pedal; brake pedal travel increases considerably.

Abstract: A hydraulic dual-circuit external power brake valve of tandem design has a primary control piston and a secondary control piston, both of which are located in a valve bore of the dual-circuit external power brake valve. The control pistons are provided with bores for connection of a primary brake circuit and a secondary brake circuit to a pressure reservoir and an equalizing tank, and are movable within the valve bore. The regulating force necessary for the motion is introduced into the dual-circuit external power brake valve by a regulating spring. A pressure-transmitting piston between the primary control piston and the regulating spring. The primary control piston on its two end faces, and the pressure-transmitting piston on its face toward the primary piston, are subjected to the pressure acting in the primary brake circuit. When the primary brake circuit is intact, the pressure-transmitting piston is actuated by the regulating spring.

Abstract: A brake booster has a first booster cylinder and a booster piston disposed in it for displacing a rod-like master cylinder piston of a master cylinder which supplies at least one brake circuit (I, II), having a tappet for mechanically displacing the first booster piston as needed if the brake boosting is inadequate, and having a brake valve coupled to the tappet and the first booster piston for direction boosting pressure into the first booster cylinder. A second, annular booster piston surrounds the rod-like master cylinder piston and likewise has a booster cylinder. Thsi second booster piston is joined to a pump piston which is likewise annular and sealingly surrounds the rod-like master cylinder piston. When the pressure supply apparatus is in operation, actuation of the brake pedal simultaneously displaces both booster pistons and generates braking pressures in the brake circuits (I, II).

Abstract: A braking pressure generator (1,21) for a vehicular hydraulic brake system, wherein a booster piston (15) which is slidable by hydraulic pressure is displaceable in the actuating direction. The booster piston (15) is arranged as a stepped piston with a smaller-diameter portion (16) close to the pedal. The booster piston (15) includes a blind-end bore remote from the pedal in which a master cylinder piston (43) is sealedly guided, wherein the smaller-diameter portion (16) of the booster piston (15) confines an annular chamber (18) diminishing upon brake application. A valve (30) is connected to the annular chamber (18) controllable by the pressure in the pressure chamber (14) of the hydraulic power booster. The valve closes a connection between the annular chamber (18) and an unpressurized supply reservoir (9). A direct connection can be established between the annular chamber (18) and the working chamber (22) by way of the valve (30) and by circumventing a sealing collar.

Abstract: A hydraulic brake system with slip control comprising a master cylinder (2) pressurizable by a hydraulic power booster (1). A booster sleeve (52) is provided which annularly encloses the booster piston (4), and which is slidably accommodated in the booster housing. The sleeve's end face directed towards the pressure chamber (10) of the booster (1) is applied by the pressure in the pressure chamber (10), while an annular chamber (59) filled with pressure medium and connected to a brake circuit (32) is constituted between the booster sleeve (52) with its head portion (61) and the bore (60) in the booster housing. The booster sleeve (52) is coupled to the booster piston (4) by way of a circlip (53) such that, on movement of the booster piston (4) in the direction of brake actuation, the booster sleeve (52) and the booster piston (4) will displace uniformly.

Abstract: An improved booster for use with a master cylinder in a brake system is proposed which includes a spring for keeping the input shaft away from the booster piston. The spring has one end abutting on a piston acted by the auxiliary pressure from the auxiliary power source and the other end abutting on the brake pedal to bear the pedal stepping force. The input shaft will not engage the booster piston except in case of the failure of the auxiliary power source, ect.

Abstract: A brake pressure generator for an automotive hydraulic brake system, wherein a booster piston (13) which is displaceable by an auxiliary hydraulic pressure in the direction of actuation is adapted to mechanically strike an annular piston (18) and is displaceable in the actuating direction. Sealingly guided within the annular piston (18) is a master cylinder piston (25) confining at least one working chamber (23) separable from an unpressurized supply reservoir (32), by a valve (31) controllable in way-responsive manner. Annular piston (18) is of a stepped-piston configuration and is provided with a section (19) facing pedal actuation (6) and being of a smaller diameter. According to the invention it is suggested that the pedal-sided section (19) of annular piston (18) is of a smaller diameter than that of the booster piston (13) to confine an annular chamber (22) which via a check valve (33) adapted to be switched open toward working chamber (23), is in communication with working chamber (23).

Abstract: A hydraulic brake booster including main cylinders operative relative to a pedal stroke by which a sufficient pedal stroke is still available in the event of a failure in the pressure supply so that the brakes can be actuated by the pedal stroke and furthermore flooring of the brake pedal is avoided in the event of failure of the fluid medium power supply.

Abstract: A pressure-fluid-operable vehicle brake system is proposed, which is fed by an auxiliary energy supply system (3) and which comprises a master cylinder device (1), in which a booster piston (40) adapted to be acted upon by the auxiliary energy is slidable in a pressure fluid chamber (26). When the auxiliary energy supply system (3) is intact, the booster piston (40) comprises an effective area for the pressurization of a wheel brake cylinder which is larger than an effective area which results upon failure of the auxiliary energy supply system. Upon failure of the auxiliary energy supply system (3), the necessary deacceleration is achieved because of a smaller effective area at the booster piston (40) and at a greater displacement travel of the booster piston (40) and with less pedal force (F).

Abstract: A vehicle brake booster comprises a brake master cylinder operable by a brake pedal, and a power valve including valve means operable by the brake pedal to admit fluid under pressure from a source to a boost piston for applying a boost force to the master cylinder and to apply a reaction force to the brake pedal, the valve means are movable against a spring by fluid under pressure from the source from an inactive position to an active position so long as fluid under pressure is available.

Abstract: The invention relates to a master cylinder for an automobile braking circuit which is suitable for dual-circuit or single-circuit application.The master cylinder has at least one chamber connected to the braking circuit, the pressure in the chamber being controlled by depression of a master piston by a brake pedal.

Abstract: The invention relates to a hydraulic brake booster for a vehicle brake apparatus which is provided with a pressurizing apparatus which has a pump and a reservoir. When the reservoir pressure fails, a switchover piston which is subject to the reservoir pressure can disengage a stop for the push rod of the control valve.The push rod is supported on the stop when the pressure supply to the reservoir is intact and after the control valve switches over in the direction of brake activation, in order to give the driver a sense of the added brake force. In the same event, a support of a pedal activation stem on a movable auxiliary cylinder is removed. When the reservoir pressure supply fails, however, this support is made available, in order to enable an immediate mechanical actuation of the main cylinder portion of the brake booster.

Abstract: The hydraulic brake booster power piston has a rectangular cross section seal groove containing a rectangular cross section lathe cut seal having a greater inner diameter than the groove as well as a greater outer diameter. Radial clearance is provided between the piston and the cylinder wall. The groove has one or more holes at its inner diameter opening axially into the booster power pressure chamber. The seal is also axially thinner than the groove. Power pressure holds the seal in sealing relation with the cylinder wall and the piston. When fluid must flow from the exhaust chamber side of the piston to the power chamber side (e.g. during manual no-power operation) the seal moves to the other groove side, allowing flow radially inward in the groove and past the seal inner periphery through the hole or holes to the power chamber.

Abstract: A power brake unit for automotive vehicles includes a brake valve to meter brake fluid from an auxiliary fluid source into a booster chamber to act upon a booster piston arrangement. The booster piston arrangement includes a first booster piston and a second booster piston, the latter being held in an operative position by the fluid from the auxiliary fluid source and being inoperative in the event of failure of the auxiliary fluid source. If the auxiliary fluid source fails, the brake pedal force is directly and mechanically transmitted from the brake pedal to the master cylinder piston.

Abstract: The invention provides an assisted braking device which operates in conjunction with a brake pedal disposed at one end of a brake lever. The device comprises a master piston and cylinder assembly the piston of which is interconnected with the piston of an assisting jack by means of a connecting element on which is articulated the brake lever. The end of the brake lever remote from the brake pedal acts on a distributor adapted to feed the assisting jack with assisting hydraulic pressure so that when a force is applied to the brake pedal and thereby to the master piston via the connecting element, the distributor directs hydraulic fluid under pressure to the assisting jack, the piston of which then applies an assisting force to the connecting element.

Abstract: A master cylinder includes a master cylinder piston which is slidable by a booster with a hydraulic transmission interposed between the booster and the master cylinder piston. The booster includes two booster pistons the first of which has the same effective area as the master cylinder piston. With the system intact, the master cylinder piston is shifted as a result of the pressure fluid displaced by the two booster pistons to provide the hydraulic transmission. In the event of failure of the booster, the master cylinder piston is actuated directly by mechanical means through the first booster piston with the hydraulic transmission thereby being omitted.

Abstract: The device comprises a master piston and cylinder assembly the piston of which is interconnected with the piston of an assisting jack by means of a connecting element on which is articulated the brake lever. The end of the brake lever remote from the brake pedal acts on a distributor adapted to feed the assisting jack with assisting hydraulic pressure so that when a force is applied to the brake pedal and thereby to the master piston via the connecting element, the distributor directs hydraulic fluid under pressure to the assisting jack, the piston of which then applies an assisting force to the connecting element.In the improvement of the invention, an abutment surface is provided for the brake lever located between the articulation point of the lever and its point of contact with the distributor so as to increase the mechanical advantage of the brake lever in the event of failure of the assisting hydraulic system.

Abstract: A power operated actuator assembly incorporates a stop mechanism for opposing movement of an actuating member if a booster fluid supply is operative. The stop mechanism comprises a chamber which is supplied with a metered proportion of pressurized fluid when the actuating member is moved such that the greater the force on the actuating member, the greater will be the magnitude of the force due to the pressurized fluid opposing movement of the actuating member.