Abstract: A manually/electrically operated brake system for applying a brake to a wheel of a vehicle, including a master cylinder operated by a brake operating member, to generate a manually controlled braking pressure according to an operation of the brake operating member, a wheel brake cylinder for applying a brake to the wheel, a primary fluid passage for connecting the master cylinder to the wheel brake cylinder, an electrically controlled pressure generating device for generating an electrically controlled braking pressure to produce a required braking effect determined based on at least one of an operating force and an operating stroke of the brake operating member, and a switching device provided in the primary fluid passage, for applying the electrically controlled braking pressure to the wheel brake cylinder while disconnecting the master cylinder from the wheel brake cylinder when the electrically controlled pressure generating device is normally functioning, and for applying the manually controlled braking

Abstract: A hydraulic brake system with anti-skid control and/or traction slip control has a braking pressure generator (1, 21), a pressure compensation reservoir (4, 4',24, 24', 42), braking pressure control valves (7, 8 V.sub.1 -V.sub.4, AV.sub.1 -AV.sub.4) by which pressure medium can be tapped from the wheel brakes of the controlled wheels in the braking pressure reduction phase. Further, there is provided an auxiliary pressure supply system (10, 10') by which, in case of control, it is possible to supply pressure medium into the wheel brakes. To increase the operational reliability of the brake system, a pressure compensation chamber (18, 28, 28', 28", 39, 39') with a non-return valve (19, 29, 29', 29", 44, 46) connected upstream and opening toward the pressure compensation chamber is inserted into the pressure medium paths from the pressure compensation reservoir (4', 24, 24', 42) to the auxiliary pressure supply system. The outputs of the outlet valves (AV, AV.sub.1 -AV.sub.4, AV.sub.1 '-AV.sub.

Abstract: A vehicle brake system, with the usual arrangement of a power booster axially aligned with the brake master cylinder piston and engaged between it and the brake pedal, has a fluid pressure differential-operated actuator offset from the conjoint axis of the power booster and the master cylinder piston. The actuator is coupled to the master cylinder piston through a mechanical linkage which provides a substantial mechanical advantage. The actuator causes the brakes to be applied independent of the brake pedal in response to any of several sensed conditions which dictate that the vehicle should not be moving.

Abstract: Hydraulic booster comprising a housing provided with a bore inside which there is slidably mounted two pistons each associated with a respective pressure chamber intended to be connected to a respective brake circuit; an actuating piston slidably mounted inside the bore and intended to be displaced by a brake pedal, displacement of the actuating piston being capable of causing displacement of the two pistons; and two valve mechanisms each associated with a respective brake circuit and intended to control the flow of pressurized fluid from a respective source to the brake circuit, characterized in that the two valve mechanisms are arranged parallel to the bore and are intended to be actuated simultaneously by the actuating piston.

Abstract: A brake pressure control unit operable by a hydraulic brake power booster and functionally corresponding to a tandem master cylinder for two statically pressurizable brake circuits has two casing bores spaced laterally apart. In one of the bores, the primary output pressure space bounded by the primary piston and floating piston is accommodated, and in the second bore, a piston which is also a floating piston, bounds the secondary output pressure space by a piston flange. The floating piston bounding the primary output pressure space on one side has the effect of building up, in the end control pressure spaces of the first and second bores, the control pressure acting on the second floating piston. This pressure leads to a displacement of the second floating piston in the sense of a pressure build-up in the secondary pressure space. The second floating piston is connected to a double-acting hydraulic cylinder, which is likewise accommodated in the second casing bore.

Abstract: A brake system wherein an input from an operator operates a first master cylinder (12) produces first and second hydraulic fluid pressures. Flexible conduit (22 and 24) carries the first and second hydraulic fluid pressures to an actuator (26) for a hydraulic power booster (28). A plunger (58) in the actuator (26) reacts either to the first hydraulic fluid pressure or the second hydraulic fluid pressure by moving to operate the hydraulic power booster (28). Operation of the hydraulic power booster (28) provides an input force to develop first and second operation fluid pressures in a second master cylinder (30) to effect a brake application.

Abstract: A brake unit for a road vehicle with a hydraulic dual-circuit brake system having two master cylinders, the brake booster and elements for antilock and/or propulsion or slip control in a common housing. A brake booster drive cylinder which can be subjected to the outlet pressure, proportional to the pedal travel, of a brake valve, is arranged between static master cylinders. Coupled to the piston of the drive cylinder is a pivotable rocker, the arms of which are each supported on one of the master cylinder pistons via tappet. Assigned to at least one of the master cylinders is a regulating cylinder having an opposed piston which can be supported on the piston of the master cylinder and which, when subjected on one side to the outlet pressure of the auxiliary pressure source of the brake booster, causes the piston of the master cylinder to be returnable towards its basic position counter to the actuating force exerted on it.

Abstract: The combination accumulator and variable volume sump (50) comprises a housing (52) having therein a stepped bore (56). An H-shaped piston and a U-shaped piston (60, 80) are diaposed within the stepped bore (56), the first piston comprising an accumulator piston (60) and defining with the housing (52) and stepped bore (56) a first chamber (70) containing therein pressurized medium. The second piston (80) defines with the housing (52) and stepped bore (56) a second chamber (90) containing therein pressurized fluid. Open ends of the U-shaped pistons (60, 80) are received one within another, and a spring (95) is disposed between interior openings (62, 82) of pistons (60, 80) to bias them apart. The housing (52) has a pair of openings (54, 59) for communicating pressurized fluid, one opening (54) communicating with the second chamber (90) and the other opening (59) communicating with the stepped bore (56) in order to communicate pressurized fluid to the first piston (60).

Abstract: A device for controlling the pressure in an auxiliary-pressure supply system of a hydraulic brake unit for automotive vehicles, which device comprises a diaphragm-type or bladder-type accumulator equipped with a hydraulic and electric switching arrangement by way of which the hydraulic pressure in the pressure accumulator can be reduced to a predetermined value after the engine of the vehicle has been turned off. An electromagnetic multidirectional control valve is used to divert hydraulic fluid back to a reservoir through a pressure-limiting valve connected downstream thereof. After the engine of the vehicle has been turned off, the multidirectional control valve remains open until the accumulator pressure has decreased to at least the gas inflation pressure of the accumulator. The invention reduces permeation of gas molecules through the diaphragm of the accumulator into the hydraulic fluid and thus effects a longer useful life of the pressure accumulator.

Abstract: A hydraulic brake system comprising a pedal-operated brake booster (5), which is connected with the master cylinder (3) and includes an auxiliary pressure supply system (13), a booster piston (4), and a booster chamber (7) wherein an auxiliary pressure is established which is proportional to the foot pressure (F). The hydraulic brake system is provided with wheel brakes (14,15,16,17) connected to the master cylinder (3), a filling stage cylinder (18) is provided which displaceably houses a two-stage piston (20). A pressure chamber (21) is arranged in front of the large stage (83) of the two-stage piston (20) and a filling chamber (22) is arranged in front of the small stage (84) of the two-stage piston (20). In this arrangement, the filling chamber (22) communicates with one of the working chambers (26) of the master cylinder (3) and/or a brake line (28) by way of a pressure line (25).

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: Hydraulic assistance device comprising a housing (10) provided with a bore (12) in which a piston mechanism (30, 42) is slidably mounted, which mechanism is displaceable by a brake pedal between a first position linking a first chamber (38, 56), connected to a brake circuit (60), with a low-pressure reservoir and isolating this chamber (38, 56) from a high-pressure fluid source (66), and a second position isolating the chamber (38, 56) from the low-pressure reservoir and linking it with the high-pressure source (66), the piston mechanism (30, 42) being displaceable by the brake pedal in the event of failure of the high-pressure circuit (66) thereby producing pressure increase in a second chamber (69) connected to the brake circuit (60), characterized in that the working area of the piston mechanism (30, 42) is equal to the cross-section of the bore (12).

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: A hydraulic brake system for automotive vehicles with a master brake cylinder and with a hydraulic power booster (1) connected upstream of the master brake cylinder, in which a pressure medium pump (6) drivable by an electric motor (9) is employed for providing auxiliary hydraulic energy. The drive of the pressure medium pump (6) may be switched on by a pressure contact (13) of a pressure accumulator (4), on the one hand, and by a brake pedal contact (11), on the other hand. In the unbraked operation of the automotive vehicle, the pressure medium accumulator is permanently kept on a pressure level sufficient for an initial actuation of the brake. A valve assembly is provided which establishes a hydraulic connection between the outlet of the pressure medium pump (6) and the pressure port of the hydraulic power booster (1).

Abstract: Hydraulic assistance device, incorporating a casing (10) provided with a bore (12) in which first piston means (16, 18) is slideably mounted, the piston (16, 18) being able to move under the effect of the actuation of a brake pedal between a first position allowing communication between a first chamber (72) which is connected to a braking circuit (70) and a low pressure reservoir (40), and isolating this chamber (72) from a source of high pressure fluid (76), and a second position isolating the chamber (72) from the low pressure reservoir (40) and causing it to communicate with the high pressure source (76), the device also incorporating a second chamber (38) formed in the casing (10), the communication between the first chamber (72) and the reservoir (40) incorporating a second bore (52) in which a control piston (54) of second piston means (54, 60) is slideably mounted, incorporating a bore (56), the first piston having a bore in which a plunger (31) is slideably mounted, the plunger (31) joining the first

Abstract: A hydraulic brake system comprises a pedal-actuated tandem generator cylinder (3), an auxiliary-pressure supply system with electromotively driven pump (8) and pressure fluid supply reservoir (31) and an auxiliary-pressure control valve (7, 67). The tandem generator cylinder (3) is provided with a bore (24) extending wherethrough is an actuating rod (25, 72) which acts upon a primary piston (4, 68) and whose end remote from the primary piston (4, 68) cooperates with an initial-pressure piston (16) or a vacuum brake power booster (84) slidably supported in the bore (24) and being in turn coupled with the brake pedal (19) by way of a piston rod (17, 86). An annular piston (26) is displaceably arranged in the bore (24) between the primary piston (4, 68) and the initial-pressure piston (16) or, respectively, the force-output member (74) of the booster (84).

Abstract: A hydraulic brake system (FIG. 2) composed of a master cylinder (30) coupled to the brake pedal (46), wherein there is provided a hydraulic booster (31) with a booster piston (91) and a booster chamber (35), and an auxiliary pressure proportional to the pedal force (F) develops in the booster chamber (35) during braking by way of a brake valve (6) actuated by the brake pedal (46). With the booster (31) intact, the auxiliary pressure prevailing in the booster chamber (35) acts by way of a pressure line (85, 87) on the two-stage piston (20) of a fast-fill cylinder (18), whose small stage (95) is immersed into a filling chamber (22) and, during the brake action, presses the pressure fluid available in the filling chamber (22) by way of pressure line (33) into the one brake line (37) connected to the working chamber (34) of the master cylinder (30).

Abstract: A hydraulic vehicle brake system with anti-locking, wherein a braking pressure generator (25) comprising a hydraulic power booster (26) and a master cylinder (27) connected downstream thereof is employed for the pressure supply of the brake circuits. Wheel brakes (37, 34) are connected to the pressurizable working chambers (31, 32) of the braking pressure generator (25) by way of first valves (33, 36), while the working chambers (31, 32) are connectible with an auxiliary pressure source (1) by way of second valves (46, 146). A third valve (60) is interposed between the auxiliary pressure source (1) and the second valves (46, 146), which can be switched to assume an open position in response to a pedal contact (6) and sufficient pressure of the auxiliary pressure source (1).

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 brake system for automotive vehicles with a master brake cylinder (51) and with a hydraulic power booster (49) connected upstream of the master brake cylinder, in which a pressure medium pump (18) which may be driven by an electric motor (17) is used for providing an auxiliary hydraulic energy, the drive of which may be switched on by a pressure accumulator (1), on the one hand, and by a brake pedal contact (58), on the other hand, in the unbraked operation of the automotive vehicle the pressure accumulator (1) permanently being kept on a pressure level sufficient for an initial actuation of the brake and the charge of the pressure accumulator (1) being monitored by a pressure control valve (19).

Abstract: A hydraulic brake booster includes a housing with a bore for receiving a first piston, a second piston and a valve assembly. The valve assembly includes a sleeve with a bore receiving a first valve member and a second valve member. The valve member cooperates with an input member to define a cavity within the sleeve and a resilient travel block is disposed within the cavity in engagement with the valve member and the input member.

Abstract: Hydraulic brake systems are known which comprise antiskid control valves and a pressure fluid source where pressure fluid is fed via a valve device and an antiskid control valve to a wheel brake cylinder. The pressure fluid source includes two jointly driven pumps. The disadvantage of such a system is the constant presence of a high pump output although this high output is only rarely required. Therefore, according to the present invention, an energy saving is realized by having the suction connection of a first of two jointly driven pumps connected to a pressure fluid reservoir and the suction connection of a second of two jointly driven pumps connected to the pressure fluid outlet of an antiskid control valve.

Abstract: A braking apparatus (28) includes a housing (38). The housing (38) includes therein: a master cylinder section (40) for supplying pressurized fluid to the brakes (24) of an automotive vehicle (10) to effect a brake application, a hydraulic booster section (42) for assisting the master cylinder section (40) to effect a brake application, a fluid pumping section (44) driven by an electric motor, for supplying pressurized fluid to the hydraulic booster section (42), and a reservoir section (46) supplying a single fluid to the sections 40, 42, and 44. The electric motor driving the fluid pumping section (44) receives energy from the vehicle (10) only in response to a need for braking. The brake booster (28) includes a fluid pressure accumulator (147) providing pressurized fluid to the booster section (42) during a brake application. The accumulator (147) also provides for power-assisted braking in the event of a failure of the motor-driven pumping section (44).

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: A working fluid supply system for a hydraulic power booster and a power steering system includes first and second fluid supply pumps, a hydraulic power boosting apparatus, a power steering unit, various fluid passages connecting thereto and a control apparatus. The first pump supplies pressurized working fluid to a first inlet port of the hydraulic power boosting apparatus. The second pump, controlled by the control apparatus, selectively supplies pressurized working fluid to a second inlet port of the power boosting apparatus to render the fluid supply flow rate applied to the power boosting apparatus substantially constant at a predetermined level when the fluid discharge rate of the first pump is less than the predetermined level. By this, a sufficient amount of pressurized working fluid is supplied to the hydraulic power boosting apparatus to fully operate it under all actual engine speeds.

Abstract: A hydraulic positioning system for precisely and rapidly positioning objects of the type likely to impose impact loadings on the system. The system is particularly adaptable for use in sawmill setworks for precisely positioning logs preparatory to sawing thereof. High impact loads are compensated for by special rapid-acting shock-absorbing hydraulic relief circuitry responsive to differences between impact overpressure and system pressure.

Abstract: A brake master cylinder device includes a first and a second cylinder bore formed within a body. A piston member is formed with a first piston and a second piston, which are respectively engaged with the first and the second cylinder bores to define a first and a second cylinder chamber, the arrangement being such that when the piston member is moved in a certain direction the volumes of both the first and the second cylinder chambers are reduced together. The piston member is biased in the direction opposite to said certain direction. A fluid conduit opens from the second cylinder chamber for connection to a brake actuator. A means for transferring fluid allows brake fluid to pass substantially freely from the first cylinder chamber to the second cylinder chamber. A fluid accumulator is communicated with the first cylinder chamber, and commences to accumulate fluid from it when the pressure in it rises to a predetermined pressure value.

Abstract: In a power braking system for a vehicle a supply of fluid from a power source is utilized to augment the output pressure to be supplied to a brake from a pedal-operated brake control valve assembly. The power source comprises a source of hydraulic fluid of a type different from that which is supplied to the brake from the control valve assembly, and the fluid under pressure from the pressure source is supplied to at least one pressure converter which is adapted to pressurize hydraulic fluid in a sub-system to augment the output pressure from the control valve assembly. The sub-system is provided with hydraulic fluid of a type different from that of the power source, and an hydraulic accumulator is incorporated in a line between the pressure converter and the control valve assembly.

Abstract: A hydraulic pressure actuated power brake system having a hydraulic power booster with operating pressure on both sides of the power piston power wall. The booster is therefore hydraulic pressure suspended so that the hydraulic pump of the system need not be operating to maintain this pressure while the booster is inactive. An accumulator is also charged by this pressure to provide power brake booster operation for several booster actuations without recharging by the pump. When the pump is operating, a pilot valve which is sensitive to a drop in booster operating pressure will control charging or recharging the accumulator and booster from pressure generated by the pump to maintain a desired charge pressure. A pressure relief valve will also prevent overcharging of the accumulator and booster. A check valve prevents loss of booster operating pressure toward the pump outlet if the pump pressure falls below the charged pressure.

Abstract: A hydraulic pressure actuated power brake system having a hydraulic power booster with operating pressure on both sides of the power piston power wall. The booster is therefore hydraulic pressure suspended so that the hydraulic pump of the system need not be operating to maintain this pressure while the booster is inactive. An accumulator is also charged by this pressure to provide power brake booster operation for several booster actuations without recharging by the pump. When the pump is operating, a pilot valve which is sensitive to a drop in booster operating pressure will control charging or recharging the accumulator and booster from the pressure generated by the pump to maintain a desired charge pressure. A pressure relief valve will also prevent overcharging of the accumulator and booster. A check valve prevents loss of booster operating pressure toward the pump outlet if the pump pressure falls below the charged pressure.

Abstract: A master cylinder provides a housing defining a reservoir and movably carrying a pair of pistons within a bore in communication with the reservoir. The pair of pistons cooperate with the housing to substantially define a pair of pressure chambers which communicate with respective brake circuits. One of the pistons forms a cavity to receive a reaction piston and the one piston also carries a proportioning valve. The reaction piston forms an auxiliary chamber within the one piston and the proportioning valve is exposed to the auxiliary chamber. The reaction piston extends outwardly into one of the pressure chambers to engage the housing and the valve member is responsive to the fluid pressure in the other pressure chamber to control fluid communication between the auxiliary chamber and the reservoir.

Abstract: The charging valve comprises a pressure port connected with a pressurized fluid source, a first user port which is connectible to a first user component, a second user port which is connectible to an accumulator and to a second user component of the closed center type and a valve device which is switchable dependent upon the pressure existing in the accumulator. The valve device, below a predetermined pressure in the accumulator, connects the pressure via a throttle with the second user port and, above a predetermined pressure in the accumulator, connects the pressure with the first user port. The valve device includes a closing valve which is controlled by a control pressure and the closing valve closes the connection of the pressure port with the first user port, if the pressure in the accumulator is below the predetermined pressure. Further, the closing valve can only be closed by the control pressure if the center of the second user component is open.

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: Actuating equipment for a gate valve or penstock uses both compressed air and hydraulic oil to obtain the advantages of both. A control valve directs air to a hydraulic reservoir so as to drive oil at the air pressure into one chamber of a double acting cylinder and piston connected to the gate. When the gate is not being moved it is locked in position by an air operated valve preventing oil flow. A normally energized solenoid operated control valve opens when electrical power fails so as to direct stored air from a reservoir to move the gate to a fail-safe position.Air pipelines may provide communication over some distance from the control valves to the gate valve or penstock.

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: A hydraulic brake booster for a vehicle brake system which has a control valve, actuatable via an excursion-limiting spring, which directs the flow of pressure medium from a supply source as an auxiliary force means. The excursion-limiting spring disposed subsequent to the brake pedal provides for sensitive response on the part of the control valve. In event the auxiliary force fails, the excursion-limiting spring is made ineffective so that pedal travel does not occur without being utilized. A shut-off mechanism is included to make the excursion-limiting spring ineffective has a shut-off member dependent on brake actuation and to which a motion pulse dependent on brake actuation can be imparted in the area of its outset position. In this manner, the shut-off mechanism is used during each occurrence of braking and thus cannot seize as a result of corrosion.

Abstract: A hydraulic brake booster provides a housing within which a spool valve is slidably mounted. The housing forms a pressure chamber and the spool valve is movable from a first position venting the pressure chamber to a second position, communicating the pressure chamber to a fluid pressure source as the spool valve moves toward the second position. A piston or cylindrical accumulator is also slidably mounted in the housing and moves in response to pressurized fluid in the pressure chamber to actuate braking. In order to hydraulically actuate braking when the pressure source is disabled, the piston includes a storage chamber within which pressurized fluid from the pressure chamber is stored. With the source disabled an operator actuating means moves the spool valve to the second position to close the pressure chamber to the pressure source.

Abstract: A hydraulic brake pressure control installation with a master brake cylinder actuatable by a plunger of the pedal. The plunger acts on the master brake cylinder by way of a piston rod of an adjusting cylinder which is arranged ahead of the master brake cylinder and which includes a connecting nipple on the side of the adjusting cylinder piston facing the brake pedal, with which a feed line leading to an electro-hydraulic two-stage control valve is connected. The control valve is adjusted by a control signal, and is operable to connect the feed line with either with a supply pressure line or with a pressureless return line.

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.

Abstract: A hydraulic brake booster includes a housing which substantially defines a pressure chamber and the housing slidably supports a control valve for communicating pressurized fluid to the pressure chamber. A piston is movably disposed within the housing to move in response to pressurized fluid within the pressure chamber and the piston substantially defines a storage chamber located inside the piston. A charging valve communicates pressurized fluid to the storage chamber and a relief valve vents the storage chamber to the pressure chamber when the pressure stored in the storage chamber is above a predetermined value. An input member cooperates with the piston to define an actuating cavity which communicates with the relief valve so that the input member is movable relative to the piston to pressurize the actuating cavity which causes the relief valve to open communication between the storage chamber and the pressure chamber.

Abstract: An installation for the servo-assist of actuating devices in motor vehicles, especially of a hydraulic brake system, in which a control member, such as the brake pedal, acts on an actuating device, such as a master cylinder of a two-circuit brake system by way of a servo-member; a hydraulically actuatable servo-unit is thereby arranged between the control member and the actuating device whose first part is supported at the control member and whose second part is connected with the actuating device; the actuation of the servo-unit is controllable from a hydraulic pressure medium source in the manner of a follower control by means of a control device connected with the control member.

Abstract: An integrated control mechanism for regulating the communication of pressurized fluid from a source to a brake system and a steering system of a vehicle in response to independent operator brake and steering signals. The integrated control mechanism has a housing with a bore therein connected to a single source of fluid under pressure. A rotary valve located in the bore is rotated in response to an operator steering signal to control the communication of the pressurized fluid to the steering system from the bore and thereby provide a power assist in steering the vehicle. A spool valve, concentrically located in said bore with respect to said rotary valve, linearly moves in response to an operator braking signal to control the communication of the pressurized fluid from the bore to the brake system and thereby provide a power assist in effecting a brake application.

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.

Abstract: In a pneumatic brake booster, positive and variable pressure chambers on opposite sides of a spring loaded diaphragm piston both communicate with an air pressure source under inoperative condition of the booster; only the positive pressure chamber communicates with the air pressure source while the variable pressure chamber communicates with atmospheric pressure in response to activation of the booster to operate the piston.

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 (accumulator). 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 this manner, a stop for the brake pedal, which activates the push rod is formed which is subject solely to the resiliency of a travel-limiting spring. The stop operates when reservoir pressure is available to effect a longer pedal stroke. When the reservoir pressure fails, it is automatically disengaged.

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 interconnected that the master cylinder can be operated manually when there is no or insufficient power pressure to operate either booster section. It may also be operated by actuating the vacuum suspended booster section, and, when no hydraulic pressure is available to the hydraulic booster section, this operation may be followed by manual actuation. It may be operated by initially actuating the hydraulic booster section when there is no vacuum available for initially operating the vacuum suspended booster section, followed by manual actuation as needed.

Abstract: The brake booster is connected in the hydraulic circuit containing the vehicle's power steering system. It is placed downstream of the power steering gear. A multi-functional accumulator/relief valve is provided. This valve functions as the flow restriction seat portion of the control valve to normally operate the booster, provides pressure relief to limit boost pressure to a predetermined maximum, and operates to controllably release pressure of an accumulator to the booster in the event that the power steering pump is not able to adequately perform as a pressure source for the brake booster.

Abstract: A power brake control device for vehicles disposed between a manual brake operating member and wheel brake members which includes an accumulator, a housing including a first inlet port connected to a hydraulic pressure source, a second inlet port connected to the accumulator hydraulically disposed and interconnected between the pressure source and the first inlet port, a first outlet port hydraulically connected to the wheel brake members and a second outlet port connected to the reservoir. A spool valve is also slidably disposed within the housing and is movable by operation of the manual brake operating member for controlling hydraulic communication between the first inlet and the second outlet port with a piston being slidably disposed within the housing for connecting the first outlet port with the first inlet port, one end of the piston being secured to the spool valve for unitary movement therewith.

Abstract: A hydraulic brake booster mechanism for use with an open or circulating fluid pressure system includes a divider valve for the fluid flow interposed between a source of continuously circulating fluid pressure and a power steering mechanism, a control valve operatively associated with a brake pedal for applying the brakes, and a change-over valve actuated by means of the displacement of the divider valve upon the failure of the source to deliver the fluid pressure from an accumulator to the control valve for assuring an emergency application of the brakes.