Abstract: The improved apply and relief valve mechanism (111, 112, 115, 117, 119, 120, 130, 132) for a fluid power apparatus (10) comprises a valve rod (112) having at one end (114) an integral, enlarged diameter spring retainer section (119), at a second end (113) a plurality of longitudinally extending grooves or passageways (132) in the valve rod (112) and a circumferential groove (111), a generally cylindrically shaped seal/reaction piston (120, 130) attached to the second end (113) of the valve rod (112) by way of a snap ring (115) received within the circumferential groove (111), and a spring mechanism (117) disposed around the valve rod (112) to abut the spring retainer section (119) and bias the reaction piston (120, 130) into engagement with the snap ring (115). The passageways (132) in the second end (113) of the valve rod (112) provide for improved fluid flow so that the fluid power apparatus (10) will not experience self actuation.

Abstract: An improvement of a constant pressure passage formed within a valve body of a brake booster is disclosed. A notch of a given size is formed in the internal peripheral surface of the valve body at a location rearward of the rear end of the constant pressure passage. The provision of the notch allows the diameter of a reaction disc to be increased over the prior art by an amount corresponding to the depth of the notch, thus allowing the durability of the reaction disc to be improved.

Abstract: A brake booster, and more particularly, an improvement of a coiled spring which is disposed within a valve body to return an input shaft to its inoperative position is disclosed. The coiled spring of the invention is generally cylindrical, and is disposed between a retainer secured to a tubular portion of the valve body and a step on the input shaft. The coiled spring includes a seat section which is disposed in abutment against the step on the input shaft and which has an inner diameter chosen to be less than the adjacent coil. Such arrangement enables an arcuate space 20d to be maintained radially between the seat section and its adjacent coil. The arcuate space is utilized as a pressure passage which allows the passage of the atmosphere. If the coiled spring is rapidly compressed upon operation of the booster, the described space is maintained, allowing an unhindered passage of the atmosphere through the space. This improves the response upon operation of the booster.

Abstract: A brake actuator assembly for motor vehicles. A mounting plate (14) formed with a central hole (60) serves for fastening a pneumatic brake pressure booster (22) to the splashboard (10) of a motor vehicle. The brake pressure booster (22) includes a rear housing portion (50) formed with a rearwardly projecting tubular connecting piece (52) which is pushed from the front through the central hole (60) in the mounting plate (14) and through a central recess (70) presented in a stiffening plate (66) which abuts against the mounting plate (60) from the rear. In this manner the brake pressure booster (22) is centered with respect to the mounting plate (14) and the stiffening plate (66). The stiffening plate (66) is formed in one piece with support blocks (68) for a pedal arrangement (20) of the usual kind in motor vehicles.

Abstract: A method of manufacturing a tandem brake booster by selectively choosing a front shell having a first cylindrical body with first effective diameter, a transition shell having a second cylindrical body with a second effective diameter and a rear shell having a third cylindrical body with a third effective diameter. The cylindrical body of the transition shell is an integral component of an end wall which separates the interior the resulting tandem brake booster. The end wall has a peripheral ledge with a flange extending therefrom and a groove located on the flange connected to the second cylindrical body. An annular surface on the first cylindrical body is crimped into the groove on the flange while a corresponding annular surface on the second cylindrical body is crimped onto the third cylindrical to join the transition shell with the rear shell to form an integral unit.

Abstract: An actuating unit for a hydraulic brake system for automotive vehicles for shortening the actuating travel of the brake power booster to pre-charge the brake system. The actuating unit includes a master cylinder and a pneumatic brake power booster connected upstream thereof. A first sealing seat (10) of a control valve (9) of the brake power booster (1), which control valve is arranged in a control housing (8), is designed separately of the control housing (8) to be slidable within limits in relation thereto. The first sealing seat (10) is held on a stop (18) on the booster housing during a predefinable actuating stroke of the control housing (8) and, respectively, of a movable wall (5) generating the boosting force. After the required actuating travel of the brake power booster, the first sealing seat (10) is carried away from the stop (18) which causes a connection between the working chamber (7) and the vacuum chamber (6).

Abstract: To preclude a rolling diaphragm forming together with a metallic diaphragm plate the movable wall of a vacuum brake force booster from being detached from a groove accommodating the radially inward area of the rolling diaphragm, it is provided, in the practice of the invention, that the contour of a supporting face for the diaphragm plate formed on the control valve housing and the contour of the radially inward area (sealing bead of the rolling diaphragm correspond to the curved shaped of the radially inward area (curvature) of the diaphragm plate, and that both the contour of the supporting face and the one of the radially inward area (sealing bead) of the rolling diaphragm correspond to the curved shape of the radially inward area (curvature) of the diaphragm plate, and that the groove with the axial dimension thereof extends into the bearing area of the diaphragm plate of the support face.

Abstract: A vacuum brake power booster and a process is disclosed in which a precise adjustment of the power boost startup characteristic is achieved. The adjustment is carried out as a final step in the manufacture of the booster adjusting the distance between the valve piston and an elastic reaction distance. During adjustment, the vacuum brake power booster has a vacuum applied. A pre-established input force is exerted on the piston rod while simultaneously measuring the output force exerted by the push rod, and the axial length of the valve piston is modified until the measured output force is within a pre-established range. The adjustment is carried out by modifying the length of a two piece valve piston or by temporarily extending a rod within the valve piston until a correct output force is reached and thereafter removing the rod and inserting a transmission pin of a length determined by the extent of travel of the rod at the point at which the desired output force was attained.

Abstract: An arrangement for a master cylinder and a vacuum booster for an automotive vehicle is provided including a vacuum booster having a first travel axis generally parallel with a travel axis of a vehicle and a housing for attachment to the vehicle, a master cylinder for fluidly actuating a braking system, the master cylinder having a piston slidably mounted along a second travel axis generally perpendicular to the first travel axis, a tubular enclosed conduit relay housing having a first end connected with the booster housing having a first opening and a second opening, the relay housing being connected with and supporting the master cylinder housing at a position spaced away from the vacuum booster housing, and a relay link pivotally mounted with respect to the relay housing by the pin, the relay link transmitting force between the booster and the master cylinder via first and second pivotally connected clevises.

Abstract: A power piston assembly for booster, in particular, an improvement of an axial portion of a power piston and a retainer which is engaged therewith is disclosed. A front power piston is formed with a first and a second tubular section around its inner periphery, and the first tubular section is fitted around a flange of a valve body and is prevented from disengagement therefrom by an annular retainer. Around its outer peripheral edge, the retainer is formed with a peripheral tubular portion, which is disposed as a press fit around the second tubular section of the front power piston from the front side, thereby connecting the front power piston to the flange of the valve body. With this arrangement, the front end of the first tubular section of the front power piston may be located rearward of the front end of the valve body (or its flange). Accordingly, the axial size of the first tubular section and hence of the booster may be reduced as compared with a conventional arrangement.

Abstract: The master cylinder comprises a body 10 formed with a bore 13, a piston 19 slidable in the bore to discharge hydraulic working fluid from the bore and an annular reservoir 17 for communication with the bore 13 and which is concentric with the bore. The reservoir contains a flexible diaphragm 30 which separate fluid in the reservoir 17 from ambient air. The use of the concentric reservoir 17 and diaphragm 30 makes the master cylinder particulary compact and suitable for use in a pre-filled clutch release system of a vehicle.

Abstract: The invention relates to a pneumatic brake-booster comprising a casing (10), inside which is situated a piston (20) comprising a rear tubular part (22) and a movable wall (12) defining a front chamber (16) permanently connected to a vacuum source and a rear chamber (18) selectively connected to the front chamber (16) or to the atmosphere by a valve mechanism (20a, 32a, 40) actuated by a control rod (34) adapted to bear, by way of a plunger (32) against one face of a reaction disk (58) fastened to a push rod (56), the valve mechanism comprising a valve closure member (40) cooperating by an active part with a first valve seat (32a) formed on the plunger (32) and with a second valve seat (20a) formed on the piston (20). According to the invention, a guide mechanism (62) for the air in movement are provided upstream of the valve mechanism.

Abstract: A fluid-operated power booster includes a housing having a main piston slidably mounted therein and a regulating chamber formed in the main piston. A regulating piston is mounted within the regulating chamber and is fixed to an input shaft. The input shaft has a valve mounted on it so that movement of the input shaft and regulating piston in a first direction permits the flow of working fluid into both a working chamber and the regulating chamber, while movement of the input shaft in a second direction causes working fluid to be exhausted from the working chamber. The regulating piston is biased by a mechanical spring whose force must be overcome to initiate movement of the regulating piston and thereby the flow of working fluid to achieve booster action. The output of the device is by way of an output shaft connected to the main piston.

Abstract: The invention relates to a brake-booster (10) of a vehicle, comprising a casing (12) and a diaphragm (14) which divides in a sealed manner the interior of the casing into a front chamber (16) and a back chamber (18), a hollow piston (20) movable in the casing receiving an input member (24) adapted to be connected to a brake pedal, an output assembly comprising a lid (30) and an output rod (32) adapted to be connected to a piston (34) of a master cylinder (36), a reaction disk (28) in a deformable material arranged between the hollow piston (20) and the lid (30) so as to receive an image of the output force of the booster (10) when it is put into operation in order to cause a deformation of the reaction disk (28) tending to push back the input member (24) as a function of the image.

Abstract: An improvement of a reaction transmitting mechanism for a booster is disclosed. A forward end face of a tubular portion of a valve body which abuts against a reaction disc is provided with an uneven surface. This presents a resistance to an elastic deformation of the reaction disc when a brake booster is actuated. Accordingly, an enhanced hysteresis, which represents a difference in the output between when depressing and releasing a brake pedal, is provided without increasing the hardness of the reaction disc.

Abstract: A valving arrangement as provided for a vehicle brake booster wherein an inlet valve has two ring members. The inlet valve, by providing the two ring members, one ring member inserted within another member, is less vulnerable to leaks due to a lack of parallelism.

Abstract: A vacuum brake power booster (1) has an electric travel sensor (3) for monitoring the position of a movable wall (4) furnishing the boosting power of the brake power booster. The travel sensor (3) is mounted by a sensor receptacle (2) which is made of plastic material and which is sealed off with respect to the booster housing (10) by means of a seal. In order to assure effective sealing by creating a constant degree of compression of the seal (7) despite different material thicknesses of the booster housing (10), angled tabs (12) are formed against which locking projections (11) are abutted.

Abstract: A vacuum booster has a booster shell formed of a front shell half and a rear shell half interconnected at their open ends opposed to each other, and a diaphragm which divides the shell interior into a vacuum chamber on the front shell half side and a working chamber on the rear shell half side. An outer peripheral bead portion of the diaphragm is clamped between the open ends of both the shell halves with an outer surface of the outer peripheral bead portion being contacted under pressure with an inner surface of the open end of the front shell half. The outer peripheral bead portion is provided at an outer periphery thereof with a first tapered surface tapered toward the front shell half and a second tapered surface tapered toward the rear shell half such that the first and second tapered surfaces are formed into an angled shape in their cross section.

Abstract: A vacuum brake power booster is described wherein the return movement of a valve piston actuating a control valve is limited by a U-shaped element (17) slidable into a control housing (11). In order to improve the ventilation of the working chamber of the brake power booster initiated on actuation and to shorten the booster's response time, exit areas (42, 43, 44, 45) of ventilation ducts (38, 39, 40, 41) permitting an air flow into the working chamber (3) are formed radially outwardly of an area in the control housing (11) between the arms of the U-shaped element (17), the exit areas being confined by the outside walls (34, 35, 36, 37, 46, 47, 48, 49) of air evacuation ducts (28, 29, 30, 31) interconnecting the working chamber (3) and a vacuum chamber(4).

Abstract: A retainer for locating a poppet member of a control valve in a bore while positioning a return spring connected to an input member within bore to direct substantially turbulent free air through slots in the retainer to a poppet member for distribution to a chamber when an input force moves a plunger of the control valve away from the poppet member.

Abstract: The invention relates to a pneumatic brake-booster comprising a casing (10), inside which is situated a piston (20) consisting of a rear tubular part (22) which supports a skirt (14) and which with the aid of an unwinding diaphragm (12) defines a front chamber (16) permanently connected to a vacuum source and a rear chamber (18) selectively connected to the front chamber (16) or to the atmosphere by a valve mechanism (20a,32a, 40) actuated by a control rod (34) adapted to bear, by way of a plunger (32), against one face of a reaction disk (58) fastened to a push rod (56), the valve mechanism (20a, 32a, 40) comprising a valve closure member (40) cooperating with a first valve seat (32a) formed on the plunger (32) and with a second valve seat (20a) formed on the piston (20). According to the invention, the plunger (32) and the piston ( 20) are provided with a second valve mechanism (65, 70).

Abstract: The invention relates to a pneumatic brake-booster comprising a casing (10), inside which is situated a piston (22) consisting of a rear tubular part (22) which supports a skirt (14) and which with the aid of an unwinding diaphragm (12) defines a front chamber (16) permanently connected to a vacuum source and a rear chamber (18) selectively connected to the front chamber (16) or to the atmosphere by a valve mechanism (20a, 32a, 40) actuated by a control rod (34) adapted to bear, by way of a plunger (32) sliding in a bore (30) of the piston (20), against one face of a reaction disk (58) fastened to a push rod (56), the valve mechanism (20a, 32a, 40) comprising a valve closure member (40) cooperating with a first valve seat (32a) formed on the plunger (32) and with a second valve seat (20a) formed on the piston (20 ), a retaining member (50), for the plunger (32) disposed in a radial space (38) in the piston (20) and having an inner end region extending the bore (30) of the piston (20) and forming a stop surfac

Abstract: An improvement of a brake booster is provided which is also provided with the function to serve as an automatic braking unit. A front bead of bellows disposed in a constant pressure chamber is supported by and urged against the wall surface of a front shell by a support of a support member. When the atmosphere is introduced into the internal space within the bellows to cause the brake booster to serve as an automatic braking unit, even though the front bead of the bellows is axially pulled as the bellows expands, a leakage around a seal where the front bead is connected is prevented because the front bead is urged against the wall surface of the front shell by the support member.

Abstract: A seal (22) having a cylindrical body (56) with a first bead (66) located between a mounting flange (42) on a master cylinder (12) and end wall (74) of a front shell (72) of a brake booster (14) and a second bead (68) retained on a piston (18) located in a bore (26) of the master cylinder (12). The cylindrical body (56) maintains the piston (18) in axial alignment with an output push rod (20) in the brake booster (14) when the mounting flange (42)is positioned on bolts (75, 75') extending from the end wall (74) of the front shell (72) to aid in the assembly of the master cylinder (12) with the brake booster (14).

Abstract: The invention relates to a pneumatic brake booster comprising a casing (10), within which is located a piston (22, 14, 102) formed from a rear tubular part (22) supporting a skirt and which, by way of an unrolling diaphragm (12), defining a front chamber (16) connected permanently to a vacuum source and a rear chamber (18) connected selectively to the front chamber (16) or to the atmosphere by a valve mechanism (136, 138, 140) actuated by a control rod (34) capable of bearing, by way of the front face (32b) of a plunger (32), on the rear face (58a) of a reaction disk (58) fixed to a push rod (56), a spring (150) for the return of the control rod (34) being arranged between the skirt (14) of the piston and the plunger (32), the valve mechanism (136, 138, 140) comprising a shutter (138) made rigid by an insert (118) and interacting by an active part with a first valve seat (136) formed on the plunger (32) and with a second valve seat (140) formed on the piston (14), the shutter (138) being formed by a flexible

Abstract: A plunger for a control valve having a head with a tab located in a slot in a hub member and a cylindrical body with a threaded projection connected to the head. Rotation of the cylindrical body moves the head in the slot to establish the space relationship between a reaction disc and a face on the head. The space relationship sets the distance that a reaction disc must be extruded by a reaction force before opposing an input force. The delay in opposing an input force assures that a predetermined force is developed and immediately supplied to a master cylinder.

Abstract: A method of manufacturing a tandem brake booster wherein a rearwall is derived from the separation plate of a single brake booster. The separation plate is modified by creating a passageway therethrough and using splines on the hub which are mated with keyways in a cylindrical body that extends from a front movable wall to assure that passages between the resulting front and rear chambers are aligned. A return spring holds a seal between the cylindrical body and hub to assure cross communication does not occur between the passageways. Thereafter, any operational pressure differential created during a brake application is directed into the development of an output force to effect a brake application.

Abstract: The invention relates to a pneumatic brake booster comprising a casing (10), within which is located a piston (22, 14, 102) formed from a rear tubular part (22) supporting a skirt (14) and, by way of an unrolling diaphragm (12), defining a front chamber (16) connected permanently to a vacuum source and a rear chamber (18) connected selectively to the front chamber (16) or to the atmosphere by a valve mechanism (136, 138, 140) actuated by a control rod (34) capable of bearing by way of a plunger (32) on one of the faces of a reaction disk (58) fixed to a push rod (56), the valve mechanism (136, 138, 140) possessing a shutter (138) made rigid by an insert (118) and interacting by an active part with a first valve seat (136) formed on the plunger (32) and with a second valve seat (140) formed on the piston (14), the shutter (138) being formed by a flexible tubular diaphragm (114), the active part of the shutter (138) being located between the two ends (112, 116) of the flexible tubular diaphragm (114), a stop me

Abstract: The invention relates to a pneumatic brakebooster possessing a casing (10), within which is located a piston (22, 14, 102) formed from a rear tubular part (22) supporting a skirt (14) and, with the aid of an unrolling diaphragm (12), defining a front chamber (16) connected permanently to a vacuum source and a rear chamber (18) connected selectively to the front chamber (16) or to the atmosphere by a valve mechanism (136, 138, 140) actuated by a control rod (34) capable of bearing by way of a plunger (32) on one of the faces of a reaction disk (58) fixed to a push rod (56), a return spring (150) for the control rod (34) being arranged between the skirt (14) of the piston and the plunger (32), the valve mechanism (136, 138, 140) possessing a shutter (138) interacting by an active part made rigid by an insert (118) with a first valve seat (136) formed on the plunger (32) and with a second valve seat (140) formed on the piston (14), the shutter (138) being formed by a flexible tubular diaphragm (114), the active

Abstract: A brake booster provided with a function to serve as an automatic brake is disclosed. Bellows disposed within a shell has a rear bead which is axially held sandwiched between an annular recess formed in the inner periphery of a front power piston and a retainer which is a press fit over the outer periphery of a valve body. When the atmosphere is introduced into an internal space defined within the bellows to operate the brake booster as an automatic brake, the bellows tends to expand, whereby the rear bead becomes pulled axially and radially. However, a displacement of the rear bead is prevented by being held between the annular recess in the front power piston and the retainer, thereby effectively preventing a failure of a hermetic seal in the region where the rear bead is connected.

Abstract: A brake booster is provided having a power piston slidably mounted in a housing. In a preferred embodiment the piston has a generally radial flange. Encircling the power piston is a flexible diaphragm having along its inner periphery a bead encircling the power piston and a sheet-like section radially extending from the bead. A retaining ring has a first section extending radially outward, a second section generally parallel with the piston and a third section with teeth projecting radially inwardly. Pushing the retainer towards the flange causes the bead to be radially compressed and the third section of the retainer to be deformed. The wedging causes the retainer to be retained in place sealably connecting the diaphragm with the power piston.

Abstract: An assembled brake booster, including a method of adjusting a jump value of the booster, in which a load on a valve spring (38) is adjusted by varying the position of a threaded sleeve (50 ) along the control rod (30).

Abstract: The invention relates to a vacuum brake-booster of the tandem type comprising two compartments (22, 24) separated by a stationary plate (20), each of the compartments being divided into a front chamber and a rear chamber by way of a piston (26, 28) and of an isolating diaphragm, at least the inner edge of which is equipped with a bead (38), each of the pistons (26, 28) being fixed to a movable hub (42) containing a valve mechanism, the piston (26) of the front compartment being so fixed by way of a cylindrical sleeve (30). According to the invention, the hub (42) possesses, on its periphery, a groove (32) into which penetrate respectively the inner end (34) of the piston (28) of the rear compartment (24) and the rear end (26) of the cylindrical sleeve (30), the bead (38) of the inner edge of the diaphragm (40) of the rear compartment (24) ensuring the locking of the assembly as a whole.

Abstract: A peripheral wall of a rectangular pedestal is formed bulged on the rear wall of a booster shell and attached to a vehicle body by four connecting bolts. The wall is comprised of a pair of shorter side walls parallel to shorter sides of the rectangle connecting axes of the four connecting bolts, a pair of longer side walls each bent so as to be gradually separated farther from the corresponding longer side of the rectangle at a central portion than at an end portion thereof, and four arcuate corner walls with each corner wall connecting the adjacent shorter and longer side walls. Thus, an intermediate portion of the longer side wall of the pedestal is increased in rigidity, so that an increased burden of stress can be imposed on such longer side wall. This moderates the stress concentration around the corners, thereby improving the durability of the booster shell.

Abstract: A spring and lever arrangement for imparting a spring force to a plunger of a control valve in a brake booster by operating a solenoid member during a brake application. Movement of the plunger by an operator input force allows a pressure differential to develop across a moveable wall and produce an original output force which is supplied to a pressurizing member. Resistance to movement of the pressurizing member creates a reaction force. The reaction force balances the spring force and operator input force to terminate the development of the pressure differential while correspondingly modifying the output force supplied to the pressurizing member. A switch allows an operator terminate the operation of the solenoid to effectively obviate the spring force and allow the original output force to be produced by the operator input force.

Abstract: A diaphragm for a brake booster having an annular inner bead with first and second radial surfaces separated by an apex. The second radial surface has a plurality of indentations that extend from the apex. In response to a positive pressure differential created by vacuum in a first chamber and air in a second chamber, an output force is developed to effect a brake application corresponding to an input force. This positive pressure differential act on the annular bead to urge said first radial face into engagement with a wall to prevent communication between the first and second chambers during a brake application. In the absence of the presence of vacuum in the first chamber, the input force acts on the wall to develop an operational pressure in the first chamber to develop a negative pressure differential between the first and second chambers.

Abstract: A pedestal formed bulged on a rear wall of a booster shell and attached to a vehicle body by four connecting bolts has a pheripheral wall whose length from a general wall of the rear wall of the booster shell to a seating face wall of the pedestal becomes larger toward each of corners of the pedestal. This ensures that the concentration of a stress produced at each of the corners of the peripheral wall of the pedestal can be moderated, thereby providing an improvedment in durability of the rear wall of the booster shell and suppressing an increase in internal volume of the pedestal to the utmost.

Abstract: The control assembly for a hydraulic circuit of a vehicle having an engine compartment and a passenger compartment which are separated by an apron (22) comprises:a vacuum booster (16) having one axis (18) and including:an actuating rod (20) projecting into the passenger compartment;a shell (14) which is intended to be fastened by its periphery to the apron (22) in the engine compartment and to which a master cylinder (10) is fastened; anda cover (26) closing the shell and bearing circumferentially on the apron (22) in the engine compartment,a pedal unit for actuating the booster, including at least one pedal (30) mounted on a lever (32), the pivot (34) of which is retained by a bearing piece (36) fixed to the cover.

Abstract: A vacuum type brake booster includes a housing including a front shell and a rear shell in which a constant negative pressure chamber and a variable pressure chamber are defined by a power piston and a diaphragm, a partition for dividing the variable pressure chamber into a first variable chamber next to the constant negative pressure chamber and a second variable chamber, a normally opened valve mounted on the partition for establishing or interrupting of the fluid communication an output rod movable together with the power piston, an input rod for urging the output rod, a valve mechanism disposed with in the power piston to be operated by the input rod and used for controlling the differential pressure between the constant negative pressure chamber and the variable pressure chamber by controlling the fluid communication of the second variable chamber with the constant negative pressure chamber and the atmosphere and a normally closed valve mounted on a rear shell and the partition and disposed between the f

Abstract: In a tandem type booster, the inner peripheral end of a front booster piston and the inner peripheral bead of a front diaphragm are clamped between a front end of a sleeve fitted over an outer periphery of the piston boss and a flange provided on the piston boss, so that they are connected to a front portion of the piston boss, and a rear booster piston and the piston boss are coupled to each other in a bayonet manner by retaining pawls formed on a inner peripheral end of a rear booster piston and retaining grooves provided in the outer periphery of the piston boss. The rear booster piston, the sleeve and the piston boss are engaged with one another while preventing relative rotation therebetween, and an inner peripheral bead of a rear diaphragm is clamped between the rear booster piston and a set ring and connected to a rear portion of the piston boss.

Abstract: A vacuum booster includes a booster piston having a front surface facing a vacuum chamber, a diaphragm superposed on the rear surface of the booster piston and having a rear surface facing a working chamber adapted to be selectively put into communication with the vacuum chamber or the atmosphere, a piston boss carried on a central portion of the rear wall of the booster shell for a longitudinal reciprocal movement and provided with an annular step with which an inner peripheral bead of the diaphragm engages from the rear, and an annular stopper retained on the piston boss to abut against the inner peripheral bead from the rear. The stopper includes an annular retaining portion at an outer periphery thereof to project forwardly which has a curved front end, and the inner peripheral bead of the diaphragm is formed into a ring shape projecting rearwardly to have its outer periphery engaged with the stopper retaining portion.

Abstract: A pneumatic brake booster (10) capable of operating without being actuated by a pedal (14), possesses at least one fixed part (36) and a control rod (12) with which the pedal cooperates (14). A sleeve (30) bears against the pedal (14) and partially surrounds the control rod (12), the control rod (12) possesses a shoulder (32) forming a stop cooperating with the sleeve (30) at rest and when the brake booster is actuated by the pedal (14), and the sleeve (30) is loaded by a spring (34) maintaining the pedal (14) at a given distance from the fixed part (36) of the brake booster (10) while the pedal (14) is not actuated.

Abstract: An improvement of a liquid pressure booster provided with a reaction piston is disclosed. A guide formed on a housing (plug) is caused to project into a tubular section of a power piston. A reaction piston is slidably supported by the guide, and an input shaft is slidably supported by the reaction piston. A spring which urges the reaction piston is disposed in a clearance defined between the outer periphery of the guide and the inner periphery of the tubular section of the power piston. In this manner, the guide, a sliding portion of the reaction piston, a sliding portion of the input shaft and the spring can be disposed radially of each other while overlapping each other in the axial direction to minimize the axial size of the liquid pressure booster.

Abstract: The invention relates to a pneumatic brake-booster comprising, in series, a control rod (10) substantially fixed to a plunger (12) by a pivot mechanism (14), a reaction disk (16) and a push rod (18), the control rod (10) actuating a three-way valve with two seats (24, 26), s specific space being provided at rest between the reaction disk (16) and the plunger (12). According to the invention, one of the two seats of the valve consists of the end of a sleeve (30) coaxial with the plunger (12), a prestressed compressible mechanism (32) tending to shift the sleeve (30) and plunger (12) axially away from one another, the sleeve (30) coming axially up against one end of a piece (36) fixed to the control rod (10) after the relative positions have been set.

Abstract: The invention concerns a vacuum-type booster comprising a case divided internally into a vacuum chamber and a working chamber by a piston comprising a valve mechanism possessing a double valve (20) enabling, in the rest postion, a communication between the two chambers which are then isolated from the environment and, in the working position, an isolation of the vacuum chamber and a communication between the working chamber and the environment at atmospheric pressure, this valve mechanism being normally controlled by an actuating rod (12) extending out of the case. According to the invention, it comprises, in addition, an electromechanical device (50, 52, 54) for controlling the valve mechanism independent of the actuating rod (12).

Abstract: A brake booster such as of a tandem type having a center plate disposed within a shell is disclosed. A valve body has a stepped end face, from which a cylindrical portion extends rearwardly. The cylindrical portion extends through a rear power piston and a rear diaphragm while maintaining a hermetic seal therebetween, with a distal end of the cylindrical portion being disposed within a variable pressure chamber of a rear chamber. The internal space of the cylindrical portion defines the rear end of a variable pressure passage. This arrangement allows the rear end of the variable pressure passage (the cylindrical portion) to be disposed in radially overlapping relationship with the rear power piston, thereby allowing the external diameter of the valve body to be reduced. In this manner, the effective area of the front power piston connected to the valve body may be increased as compared with the prior art.

Abstract: There is disclosed a liquid-operated booster having a jump-up function, in which the production of an internal pressure in a reaction force chamber in accordance with a reduction of the volume of the reaction force chamber is prevented. To achieve this, a mechanism for relieving the reduction of the volume of the reaction force chamber due to a relative movement of a piston and an input member toward each other is provided at a position facing the reaction force chamber. Most preferably, this relieving mechanism is constituted by a movable small piston provided at the side of an operating input.

Abstract: A liquid pressure booster includes a power piston slidably disposed in a housing, a power chamber in the housing on one side of the power piston, the power piston having a stepped bore including smaller and larger diameter bores, the latter opening into the power chamber, a supply passage communicating the smaller diameter bore to a pressure fluid source, a first valve seat in the smaller diameter bore, a valve element slidable in the smaller diameter bore to seat upon the first valve seat from the side nearer the pressure fluid source, an annular pin abutting the valve element side nearer the larger diameter bore to move the valve element away from the first valve seat, a discharge passage axially through the annular pin and communicating between the power chamber and a reservoir, and a second valve seat formed on the free end of the annular pin to interrupt communication between the power chamber and the discharge passage upon abutment of the annular pin against the valve element, a stepped sleeve having sm

Abstract: In the booster are mounted movably a hollow booster piston (20) and a control rod (30) carrying a plunger (28) seated in the piston (20), the rear end of the plunger (28) forming a first annular valve seat (28a) concentric with a second annular valve seat (20a) carried by the booster piston (20), the first valve seat (28a) and second valve seat (20a) interacting with an annular shutter (34) carried by the booster piston (20), and a reaction disk (48) being interposed between an annular front face (20b) of the booster piston (20) and a rear face of a push rod (46). The process for adjusting the value of the pump of the booster comprises the following steps:applying to the push rod (46) a force equal to the boost force corresponding to the desired jump of the booster,moving the seat (20a) of the booster piston (20) away from the shutter (34),putting the front face of the plunger (28) and the rear face of the reaction disk (48) into contact and maintaining this contact during the next step.

Abstract: A poppet valve for a vacuum brake booster. The poppet valve is connected to a key number which retains a control valve in a bore of a hub of a brake booster. The poppet valve controls fluid communication between a first chamber and a second chamber in the booster while the control valve only controls fluid communication between the bore and the second chamber.