Abstract: A brake servo booster has a housing (1) divided into two chambers (A, B) by a movable partition (5) which includes a diaphragm (6). A protective boot (14) for a support member (11) extending through the housing is connected to the diaphragm by a carrier member (16) engaged by adjacent portions (14A, 6A) of the boot and diaphragm in a manner which avoids direct contact between these portions and facilitates assembly of the booster.

Abstract: An improved diaphragm is disclosed which partitions the interior of a shell of a brake booster into a constant pressure chamber and a variable pressure chamber. The diaphragm includes a bead which extends around its inner periphery, and which is formed with a lip extending from the side of the constant pressure chamber to the side of the variable pressure chamber. The lip is held in close contact with the outer peripheral surface of a valve body. The lip is capable of an elastic deformation in a flexible manner, whereby a good seal against the outer peripheral surface of the valve body is maintained.

Abstract: A power piston assembly of a brake booster includes a power piston including a stepped cylindrical portion having a through-hole. A diaphragm is provided on the rear surface of the power piston. The diaphragm has an inner-circumferential bead which is connected to the rear end of the cylindrical portion of the power piston. The valve body has a stepped cylindrical portion which engages with the stepped portion of the power piston and is disposed in the through-hole of the power piston with the diaphragm bead in sealing contact with the valve body. A retainer is pressed fitted into the cylindrical portion of the power piston so as to abut the front surface of the valve body to secure the valve body in close contact with the power piston.

Abstract: A brake booster which includes a control slide that is displaceably supported in a servo piston and acted upon by a piston rod under the influence of brake pressure. The control slide has bores that establish communication between a pressure chamber and a pressure source or return for power brake fluid in the pressure chamber. The control slide is intended to penetrate a control bush in a stepped bore in the servo piston, which has a radial bore for connecting the pressure source with a radial bore in the control slide toward the pressure chamber. The control bush is supported radially movably in the stepped bore.

Abstract: The setting of the dead travel of a servo-motor for assistance during braking is carried out in the factory during its assembly. For this purpose, a subassembly (68) comprising the piston (20), the operating pushrod (30) and its plunger (28), the valve head (34), the springs (38, 40) and the fixed (44) and tilting (50) keys, is placed in a setting sleeve (70). A load (F1) is exerted on the front face of the piston (20) sufficient to maintain a bearing surface (20b) permanently against a reference surface (70a) formed on the sleeve, and the pushrod (30) is freed from the action of the spring (40) by means of a fork (70a) formed on the sleeve, and the pushrod (30) is freed from the action of the spring (40) by means of a fork (72), after having pushed the plunger (28) up against the valve head (34) by applying a load (F3), the movement (.DELTA.) made by the mobile key (50) is measured between the reference surface (170a) and a shoulder formed on the plunger (28).

Abstract: A brake booster in a housing, having a servo piston slidably supported in the housing and having a piston rod protruding into the housing for transmitting a brake force. In the servo piston, a work chamber is provided for receiving brake fluid drawn after the opening of a valve from a reservoir or supply container and pumped via a pump or the like. The work chamber also communicates via a further valve or the like with a return line to the supply container. To improve valve closing and to shorten the idle travel, the valve preceding the work chamber and arranged for the admission of the brake fluid is embodied by a valve bushing in a blind bore of the servo piston and by a spring-loaded closing element, such as a ball. The valve bushing is disposed between the piston rod and the ball and is traversed by a pin or the like, capable of being acted upon by the piston rod, for lifting the ball from its valve seat.

Abstract: A hydraulic booster in which the booster piston return spring is formed as a tubular conduit to conduct hydraulic supply pressure to a closed center valve. Upon actuation, the valve opens to permit supply pressure to flow into the power chamber and by valving action controls the exhaust of pressure from the power chamber so as to establish the desired actuating pressure therein. The tubular conduit forming the power piston return spring and transporting the supply pressure to the closed center valve permits a shorter overall axial length of the hydraulic booster by accommodating the movement of the supply pressure chamber at the closed center valve. It also permits less charged supply pressure leakage by accommodating a better pressure seal arrangement.

Abstract: In a hydraulic pressure booster comprising a booster piston slidably fitted in a booster cylinder coupled to a rear end of a master cylinder, the piston having at a leading end thereof an output rod abutting against a rear end of a master piston slidably fitted in the master cylinder, an inlet valve interposed between an output hydraulic oil chamber defined to face a back surface of the booster piston and an input hydraulic oil chamber leading to a hydraulic pressure supply source, the inlet valve being opened in response to an advancing movement, relative to the booster piston, of a valve piston connected to an operating member and slidably fitted in the booster piston, an outlet valve interposed between the output hydraulic oil chamber and an outlet chamber leading to an oil tank, said outlet valve being adapted to be closed in response to the advancing movement of the valve piston relative to the booster piston, and a reaction mechanism provided between the valve piston and the output rod for transmitting

Abstract: A vacuum brake booster (12) having an input force applied to a brake pedal (20) for moving a plunger (28) to operate a control valve (24). A sleeve (98) concentric to the push rod (22) is located between the brake pedal (20) and plunger (28). A spring (94) acts on the sleeve (98) to move the plunger (28) against a stop (76) in the absence of an input force. A ramp (104) on sleeve (98) cooperates with projection (102) on said push rod (22) to define a linear dimension for the spring (94). Rotation of the sleeve (98) changes the load of the spring (94) and correspondingly the force required to initiate the operation of the control valve (24) through movement of the plunger (28).

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 stationary stop member (44) and a tilting stop member (50) limiting the stroke of the plunger (28) inside the piston (20) of a brake booster are held in place in the piston, independently of one another, by a retaining ring (46). To this end, a first end (46a) of the retaining ring is bent back against a finger (44b) formed on the stationary stop member, while the second end (46b) of the retaining ring is bent back in an axial groove (54b) formed in a stop (54) fastened to a tongue (50b) formed on the tilting stop member.

Abstract: There is described a power booster for actuating a master brake cylinder having a booster piston which is axially movable in a cylinder bore and which, with its peripheral surface, confines a pressure chamber connectible to a hydraulic pressure source and, with an end surface, confines a booster chamber that is connectible with a pressure chamber via a first closable valve passage. Via a second closable valve passage, the booster chamber is connectible with a compensating chamber connected to an unpressurized reservoir. The compensating chamber is bounded by the peripheral surface of a reaction piston and by a sleeve that is formed fast with the housing and encompasses the reaction piston. The second valve passage is disposed in a central bore in the reaction piston terminating into the booster chamber. Arranged in the central bore is an actuating rod which carries a valve element for closing the second valve passage and which extends into the first valve passage in the booster piston.

Abstract: A tandem-type vacuum booster having a partition plate providing front and rear chambers with a booster piston and diaphragm in each chamber. A piston boss is slidably supported on the partition plate and a connecting cylinder is formed on the front chamber booster piston. A press plate is provided on the piston boss and the rear booster piston and an end plate of the connecting cylinder are coupled to the piston boss by the press plate and a plurality of bolts disposed around the piston boss with the rear booster piston and diaphragm clamped between the press plate and piston boss. The front ends of the bolts are disposed to come closer to the piston boss axis than the rear ends. The bolt heads are also received in recesses provided in the press plate to prevent relative rotation between the bolts and press plate.

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: A hydraulic brake booster is proposed, in which a coupling is provided between a control valve and a booster piston. The coupling engages the control valve at a slide sheath and upon the movement of the booster piston causes it to move as well, in such a manner that tracking control is provided. A pedal push rod in this manner always keeps a certain distance from the booster piston; that is, it does not touch it. However, if the auxiliary force should fail, then the pedal push rod does touch the booster piston, and its force is transmitted mechanically.

Abstract: A one piece seal (42) having a resilient body (100) with a peripheral surface (102) on which first and second ribs (104 and 106) engage a housing (19) to establish static seals to prevent environmental air from entering a control chamber (22) and an inner surface (114) with first and second dynamic seals (120 and 128) located adjacent first and second bearing lands (116 and 118). The first and second dynamic seals (120 and 128) which surround a movable projection (38) flex to allow the projection (38) relatively radial movement while the bearing lands (116 and 118) retain the projection (38) in axial alignment during lateral movement of the wall (24).

Abstract: A vacuum brake power booster and method of manufacture is disclosed. The booster includes a guide sleeve in a bore in the control valve casing. A radial flange of the guide sleeve guides the push rod and is supported axially within the axial bore of the control valve casing. The guide sleeve is axially embraced by a retaining member in positive engagement therewith with the retaining member being positively connected to the control valve casing.

Abstract: The invention relates to a brake cylinder suitable for a hydraulic vehicle brake system, having at least one brake chamber and a brake booster, actuatable by a piston rod, with a brake valve assembly that has an inlet and an outlet for power brake fluid and communicates with a pressure chamber of the brake booster. The pressure chamber is located in a longitudinally bored housing section and is defined in the axial direction by one end of a sealed and displaceable sheath and of a rod that is sealed and displaceable within the sheath. The sheath and rod form two servo pistons for generating brake pressure in the brake chamber. The rod is displaceable in an emergency by means of the coaxially aligned piston rod. In a space-saving manner, the brake valve assembly is built into the rod and piston rod.

Abstract: A braking-power booster including a valve for controlling the pressure that acts upon the booster piston. The valve has two radially spaced valve seats, which both face toward and seal off against a valve sealing plate. With the radially inward valve seat off the valve plate, air passes through the valve. A silencer in the form of a screen is arranged directly alongside the radially inward seat that is opened off the plate. Upon air passing through the valve, the screen suppresses noise generated in the valve. The screen is of a round-wire netting, comprised of brass wire that is galvanized. The screen has a cup-shape, and its convex side faces the seat.

Abstract: A hydraulic booster includes a power piston which is inserted slidably into a cylinder member and has a tip portion which is coupled to a piston of a master cylinder, a pressure chamber disposed in the rear of the power piston, a return valve provided in such a manner as to open and close a channel for connecting the pressure chamber to a reservoir, and a supply valve disposed in such a manner as to connect the pressure chamber to a high-pressure fluid source, a high-pressure fluid being introduced into the pressure chamber as the return valve is closed and the supply valve is opened. A valve sleeve is slidably inserted in the power piston and is urged rearwardly of the power piston by a spring, and a cam portion provided in the valve sleeve is employed to open and close the supply valve.

Abstract: A pneumatic booster includes a casing, a diaphragm secured to the casing to partition the inside of the casing into a front chamber which is communicated with a negative-pressure source and a rear chamber, a valve body secured to the inner peripheral portion of the diaphragm, a vacuum valve provided in the valve body to allow the front and rear chambers to be selectively communicated with and cut off from each other, an atmospheric valve provided in the valve body to allow the rear chamber to be selectively communicated with and cut off from the atmosphere, an input rod for actuating the vacuum and atmospheric valves, and an output rod adapted to receive the force of displacement of the diaphragm. The atmospheric valve is composed of first and second valve portions provided in series along a communicating passage between the rear chamber and the atmosphere. The first and second valve portions are closed successively in the mentioned order when the atmospheric valve is closed.

Abstract: A brake booster in which a servo piston is slidably supported in a housing. The transmission of a brake force is effected via a piston rod protruding into the housing, and a work chamber is formed between the piston rod and the servo piston. After the opening of a valve, this work chamber can be filled with brake fluid from a reservoir or supply container via a pump or the like. A return line also leads out of the work chamber back to the supply container, via a further valve. To improve the closing or sealing behavior of the valves, the first valve is to be embodied for admitting the brake fluid from a valve cone, or its shoulder, the valve cone extending axially in a blind bore of the servo piston, and a valve seat formed out of a valve bushing. The second valve is likewise embodied as a seat valve, and an element connected with the valve cone cooperates with an element connected with the piston rod.

Abstract: A parking maintaining apparatus includes a solenoid-operated open/close valve which opens or closes a constant pressure passage providing a communication between a valve mechanism and a constant pressure chamber of a brake booster. A relief valve is provided which relieves a pressure within the constant pressure passage into the constant pressure chamber when such pressure exceeds a given value. The provision of the relief valve allows the pressure within a variable pressure chamber to be maintained at or below the given value through the valve mechanism under a parking maintaining condition, whereby the pressure within the variable pressure chamber can be rapidly displaced as the parking maintaining condition is to be terminated, thus eliminating a partly braked condition.

Abstract: A tandem diaphragm vacuum booster in which both diaphragm and the bead seals are made of a single rubber-like molding.

Abstract: A tandem diaphragm vacuum booster in which both diaphragm and the bead seals are made of a single rubber-like molding.

Abstract: A vacuum operated actuator has a spring biased diaphragm that is exposed on one side to atmosphere and on the other side to a vacuum chamber. An output means is connected to move with the diaphragm and carries a valve means which together with a tube a manually controlled tube operates to connect the vacuum chamber with either atmosphere or with a vacuum source so that the diaphragm and thereby the output moves with the movement and in the direction of the tube so as to provide an output force so as to move the output with a force substantially greater than the input force applied to the tube.

Abstract: A reaction mechanism for brake booster is disclosed. The end face of one end of an output shaft is formed with a recess in which a reaction disc is received. Part of the reaction disc and a valve body include projections extending into the other to establish a tight contact between part of the reaction disc and the valve body, which region is effective to achieve a hermetic seal in a reliable manner.

Abstract: A brake booster having a brake valve disposed inside a booster piston, the brake valve comprises a valve bushing including a valve seat and a slide that is pressed by a spring against the valve seat of the valve bushing. The slide is supported with play at a great distance from the valve seat, so that it can be pivoted slightly around the vicinity of its bearing. The pivotability of the slide facilitates its centering in the valve seat, so that the valve closes dependably even in the presence of bearing tolerances or valve seat tolerances. Seals required for sealing off the slide have an elastic behavior, and are disposed in the vicinity of the bearing. As a result, reliable sealing is assured despite the pivotability of the slide.

Abstract: A brake valve for brake boosters in which a slide is guided in a sheath that is supported in rounded fashion at one end face, such that the slide, along with the sheath, is pivotable and can center itself, with a bezel formed onto its end face, in the valve seat of a valve bushing. The slide and valve bushing form a valve in which the closing behavior is improved considerably by the automatic centering of the slide in the valve seat.

Abstract: A booster, for use as an automotive brake booster is disclosed which works quickly at the beginning of an operation sequence. The booster has a housing with a piston capable of sliding in the opening of the housing and acting on a diaphragm dividing the inside of the housing into a constant pressure chamber and a variable pressure chamber. An output rod is provided having a rear end portion inserted in the power piston. A reaction disk is mounted between the output rod and the power piston with a retainer mounted on the power piston on the side of the constant pressure chamber. The retainer prevents the output rod from coming off and also causes the output rod to push the reaction plate toward the piston.

Abstract: A pull-type booster includes a hollow body in which a movable wall is movably received to divide an interior thereof into a negative pressure chamber and a pressure-variable chamber. The movable wall has a tubular portion extending outwardly of the body and having an axial internal bore. The tubular portion is disposed in a room or chamber. A tubular cover member is mounted around the tubular portion to cover it and has an inlet in communication with the internal bore. An air tube has one end connected to the inlet, and the other end of the air tube is disposed outside of the room.

Abstract: A brake booster in a housing, having a servo piston slidably supported in the housing and having a piston rod protruding into the housing for transmitting a brake force. A chamber is provided in the servo piston for receiving brake fluid drawn after the opening of a valve from a reservoir or supply container and pumped via a pump or the like. The chamber also communicates via a further valve or the like with a return line to the supply container. To improve the closing behavior of the valve, the first valve for the admission of the brake fluid is formed in the chamber, embodied as a servo chamber, by a valve bushing, or its annular collar, and a valve seat in a blind bore recess in the servo piston. On the other side, the valve bushing, with a bottom, engages the inside of a bell-shaped valve seat, which together with the piston rod, or a slide connected to the piston rod, forms the valve for returning the brake fluid.

Abstract: A brake booster is disclosed which reduces an idle stroke of an input shaft, by bringing a key member which is mechanically coupled to a valve plunger into abutment against an inner wall surface of a shell when the brake booster is inoperative. The shell includes a cylindrical projection which extends rearwardly from the center thereof, and the cylindrical projection is formed with a flange which extends radially inward, with its inner periphery cut away to define an opening. A valve body includes a cylindrical portion which extends through the opening to the outside thereof. By disposing the key member for abutment against the inner wall surface of the flange, a reduction in the length of the key member is enabled. A seal member seals the cylindrical portion of the valve body, and is located rearwardly of the flange and is received within a housing which is disposed outside the shell.

Abstract: A vacuum-operated brake booster comprises an axially movable power piston and a plunger axially movable in a cavity of the power piston. A valve disposed within the cavity cooperates with seats on the plunger and power piston to regulate pressure in a variable pressure chamber. A key serves as a stop to limit travel of the power piston and plunger. The key includes a base portion and a pair of parallel legs which extend into a radial hole of the power piston. The legs straddle and press against the plunger. Elastic retainers are snap-fit onto the ends of the key member. The elastic retainers are wider than the radial hole to retain the key in the hole.

Abstract: A vacuum breaking-force booster has a sequential control valve without a response path. First and second pressure chambers are separated by a diaphragm with a diaphragm disk in it and the diaphragm disk is connected with a shaft that supports a radially inward valve seat which presses against a spring biased sealing disk. Communication between the first and second chambers is past the inner valve seat. A shiftable sleeve extends through the lid of the first of the chambers and includes a collar which engages the inside of the lid for determining the maximum extend the sleeve can move out of the lid. A pressure piston extends through the sleeve. A bridge connects the sleeve with the pressure piston for moving together. An elastomeric bellows attaches the sealing disk to the sleeves and the pressure piston; the outer valve seat is defined on the sleeve for engaging the sealing disk. A spring normally urges the sealing disk toward both of the valve seats.

Abstract: A vacuum type booster which includes a booster piston reciprocatively movable in a shell, a valve sleeve for a control valve fitted to the booster piston and having a disengagement preventive flange superposed on the piston, and a clamp plate engaged with pawls formed by cutting and bending portions of the booster piston for clamping the flange to the booster piston. The booster piston includes pairs of reinforcement ribs which cross the turning direction of the clamp plate and sandwich cutout holes resulting from formation of the pawls. A pair of the ribs on the rear side of the turning direction of the clamp plate permit the clamp plate to turn in a direction for engagement with the pawls and inhibits the clamp plate from turning in the disengaging direction. A space is provided between the outer peripheral part of the disengagement preventive flange and an engagement piece jointing part of the clamp plate body.

Abstract: An automotive vehicle braking device comprises a hydraulic master cylinder (11) having at least one piston (21) for pressurization of the wheel cylinders connected thereto with hydraulic pressure and also having a vacuum brake force booster (12) inserted between the brake pedal (52) and the piston (21). The master cylinder (11) is integrated in the construction of the vacuum brake force booster (12).

Abstract: The return spring (16) for the actuating rod (14) of the servomotor bears against a tubular stop member (18) which is slidably mounted on the rod (14) and which comes to bear, in the rest position of the servomotor, against a reference stop (22), a ring (21) being firmly fixed to the rod (14) when contacting, in an inactive condition of the servomotor, against the tubular stop member (18) after having exerted a pull on the rod (14) bringing the valve seat (12) formed by the valve plunger (13) into full contact with the valve member (10) of the distribution valve means (6) of the servomotor.

Abstract: A pneumatic booster including a housing, a power piston partitioning the interior of the housing into a front chamber and a rear chamber, with the front chamber being connected permanently to a source of a first reference pressure, the rear chamber being selectively communicated with the front chamber and a source of second reference pressure which is higher than the first reference pressure through a valve mechanism, an output shaft receiving the output force from the power piston, and an input shaft receiving an input force for actuating said valve mechanism and receiving a reaction force of the output force. There are provided a device between the output shaft and the power piston for changing the reaction force with respect to the output force on the output shaft, a mechanism for rotating the output shaft around the axis thereof, and a device for preventing the rotation of the power piston relative to the housing at least at the non-actuated condition of the pneumatic booster.

Abstract: A tandem pneumatic pressure booster in a braking apparatus for a motor vehicle, comprising a housing; front and rear movable walls; a center plate; the housing being hermetically closed by front and rear shells; front and rear variable pressure chambers; front and rear referential pressure chambers; a valve body having a control valve therein; a reaction disc containing case; a cylindrical passage member adapted to fit over the barrel of said case; the front movable wall being fixed to the case-passage member assembly, said passage member being provided with a referential pressure chamber communicating passage; and a variable pressure chamber communicating passage, whereby these parts may be formed into a configuration suitable for die casting and for improving mass productivity without deteriorating the differential pressure.

Abstract: A pneumatically operated servo booster has a housing divided by a diaphragm assembly into front and rear chambers respectively. A hub movable with the partition carries a vacuum valve seat and a plunger slidable within the hub carries an atmospheric valve seat, the seats co-operating with a spring-urged poppet valve to control fluid flow to the chamber. A stack of Belleville washers normally transmits input force from an input rod, the washers yielding at a predetermined input force to allow a cup member to engage an abutment carried by the hub, causing the hub to move relative to the valve member and temporarily open the valve seat to cause a reduction in boost compensating for the excess input force.

Abstract: The present invention relates to a booster for automobile braking systems. The booster includes a booster housing with a movable wall disposed in the booster housing and dividing the interior of the housing into a constant pressure chamber connected to a vacuum source and a variable pressure chamber. A hub member is connected to the movable wall and has a projection extending air-tightly from the housing. The hub member is slidable relative to the housing. A control valve is disposed in the hub member and is manually actuated to interrupt fluid communication between the constant and vairable pressure chambers and to introduce ambient air into the variable pressure chamber thereby to generate an operational force of said movable wall. An output member transmits the operational force of the movable wall and the manual force applied to the control valve through a reaction force mechanism to an output arrangement.

Abstract: A pneumatically operated servo-booster has a housing divided by a movable diaphragm assembly into chambers (A, B), and a hub connected to the diaphragm and forming a vacuum valve seat for co-operation with a spring-loaded valve member. A valve element movable relative to the hub forms an atmospheric valve seat for co-operation with the valve member. A sleeve co-axial with but separate from the hub carries an abutment member which forms a fixed abutment for the valve seat when the sleeve is in abutment with the shoulder of the housing. When the seat abuts the member, co-operation of the vacuum valve seat with the valve member under the action of pressure in one of the chambers maintains the atmospheric valve in a position of readiness for activation of the booster. This arrangement contributes to increased sensitivity of operation.

Abstract: In a brake booster a seal unit is provided which maintains a shell hermetically sealed in particular, in a region where a valve body reciprocates with respect to the shell and which guides the valve body in sliding contact with the shell. A portion of a seal member disposed between the shell and the valve body which is in sliding contact with the valve body is supported by a retainer to function as a bearing.

Abstract: The invention relates to a locking arrangement for a key member used in a brake booster. A key member includes an arcuate portion which surrounds substantially one-half the perimeter of a valve body, and engaging recesses are formed at the opposite ends of the arcuate portion on the inner side. A retainer surrounds substantially one-half the perimeter of the valve body at a location opposite to the arcuate portion of the key member. The opposite ends of the retainer are formed with engaging pawls on the outer side for engaging with the engaging recesses under the resilience of the retainer. Accordingly, by merely assembling the key member and the retainer with the valve body, the engaging pawls of the retainer can be automatically engaged with the engaging recesses in the key member, thereby preventing the withdrawal of the retainer and the key member from the valve body.

Abstract: The movable wall structure (4, 5) dividing the housing (1) of the booster on the inside possesses a metal plate (4) having a central annular part (6), to which are fixed a stepped tubular insert (9) protecting the reaction disk (25) and a rear tubular element (8), in which is mounted a plastic body part (7) forming communication ducts (16, 23) for the distributor valve mechanism of the booster.

Abstract: The valve member (5) of the distribution valve mechanism of the booster comprises an active part (19), cooperating selectively with the valve seats (18; 17) in the hub (8) of the piston (2) and on the valve plunger (13), and an axial undulated tubular part (24) mounted, by its rear end, on an internal end (26) of a valve-member support (27) forming bearing zones (282; 281) for a spring (31) causing the return movement of the input rod (14) and for a spring (30) biasing the valve member and mounted, by its external periphery (29), in the tubular hub (8).

Abstract: In the assembly of a master cylinder and an oil-hydraulic booster connected to the rear thereof, the master cylinder has an axial bore consisting of a forward, small-diameter bore section and a rearward, large-diameter bore section and the master cylinder piston in the master cylinder includes a small-diameter section slidably fitted in the small-diameter bore section of the master cylinder and a large-diameter section slidably fitted in the large-diameter bore section thereof. The forward end portion of the piston in the oil-hydraulic booster is formed smaller in diameter than the large-diameter bore section of the master cylinder and is arranged proximate the large-diameter section of the master cylinder piston in the master cylinder so as to enter the large-diameter bore section of the master cylinder when the booster piston is advanced.

Abstract: A vacuum booster comprising a push rod, a housing including a front and rear shells connected with each other, a power piston located in the housing and dividing an interior of the housing into a constant pressure chamber and a variable pressure chamber with a diaphragm, a valve plunger located within the power piston and a control valve member located in the power piston. The power piston has a valve seat contactable with the control valve, and the seat surface of the valve plunger is separable from the control valve member. The seat surface of the valve plunger includes a circular spherical seat surface, and a seal surface of the control valve member contacted with the seat surface includes a concave spherical seat surface which the seat surface of the valve plunger touches internally.

Abstract: The stop member (23), which forms a bearing surface (33) cooperating in abutment with an abutting member (22) carried by the actuating rod (13) of the booster so as to determine the operational dead travel of the booster, has a deformable structure (30) capable of yielding elastically when a pulling force (F) exerted axially by the abutting member (22) on the stop member exceeds a predetermined value. The deformable structure advantageously consists of at least one arm (30) integral with a mounting sleeve (28), fixed by crimping (37) onto the rear central duct (9) of the rear shell (2) of the booster housing. The abutting member (22) is secured, in a given position, to the coupling fork (15) of the actuating rod (13).