Abstract: A tandem master cylinder for hydraulic brake systems of automotive vehicles comprising a housing in whose bore a first and a second piston are sealingly and slidably disposed. The piston in the inactive position abut on stops in the housing under the action of a first and a second resetting spring and which, within the bore, confine a first and a second pressure chamber which are in communication with a first and a second unpressurized supply chamber via central valves that are open when in the inactive position. The first piston-resetting spring is anchored on the second piston, and its spring rate is greater than the spring rate of the second piston-resetting spring.

Abstract: A master cylinder assembly especially adapted for mounting in the passenger compartment of a motor vehicle in association with the clutch pedal assembly of the motor vehicle. The unit is permanently sealed and is non-serviceable so that no fluid leakage occurs in the passenger compartment as a result of attempts to service the unit. The master cylinder assembly includes a cylinder having an open rearward end and a closed forward end, an external mounting flange intermediate the ends, and an elongated reservoir mounted in piggyback fashion on the cylinder between the mounting flange and the forward end of the cylinder with the rear end of the reservoir pivotally secured to the mounting flange and with a discharge fitting on the forward end of the reservoir moving into telescopic sealing relation with a reservoir fitting on the forward end of the cylinder in response to pivotal movement of the rear end of the cylinder about the pivot axis defined between the rear end of the reservoir and the mounting flange.

Abstract: A master cylinder includes a valve that is slidably mounted in a movable piston means for limited axial movement therein between a closed position wherein the valve is sealingly engaged with the piston and an open position wherein a gap is maintained between the valve and the piston. The valve includes a passage for providing fluid communication between the supply chamber and the pressure chamber when the valve is in the open position. An orifice in the piston limits the flow of fluid from the pressure chamber to the supply chamber at least during the limited movement of the valve from the open position to closed position. An overflow arrangement on the piston is responsive to movement of the piston against the bias of a biasing device for establishing fluid communication between the passage and the supply chamber only when the valve is in the closed position.

Abstract: A compact master cylinder suitable, for example, for vehicle clutch or brake systems. An integral fluid reservoir body is connected to a piston stem extending to a piston head in the cylinder. The stem has a longitudinal passage connected to an orifice at the reservoir inlet. This orifice is valved by a valve closure member having a spherical head and an elastomeric cap. In the retracted state a stop secured to the cylinder limits movement of the piston out of the bore and the valve closure member opens to allow entry of make-up fluid from the reservoir.

Abstract: A fabricated master cylinder having a reservoir part and in interlocked cylinder part defining a cylinder bore and which a slidable piston is supported. The reservoir part that extends into the cylinder bore defines a shoulder that cooperates with a recuperation valve for forming an actuating stop for holding the makeup fluid recuperation valve in an opened position when the piston is at its at rest position.

Abstract: A master brake cylinder including a re-aspiration valve which is disposed as a central valve in pistons of the master brake cylinder. The re-aspiration valve has a porous body, comprising porous metal, which forms a flat valve seat at one end. The sealing body of the re-aspiration valve is raised gently from the valve seat even at high ambient pressure, which makes a re-aspiration valve embodied in this way particularly suitable for use in master brake cylinders of brake systems having slip control. Because the porous body comprises porous metal which differs in length from its wall surface at one end to its axis to form a conical void space. The porous body has an axial flow resistance that decreases from the outside wall inward to its axis.

Abstract: In a tandem master cylinder, the primary and secondary outlet-pressure spaces of which are respectively limited in the axial direction by the push-rod or primary piston and a secondary piston designed as a floating piston or by the latter and an end wall fixed relative to the housing. A restoring spring urging the secondary piston into its basic position is arranged in a central cavity located in the secondary piston which is limited by a blind bore of the latter. The restoring spring is supported on the piston side on the inner face of the bottom of a pot-shaped supporting projection facing toward the primary piston and belonging to the secondary piston and, on the housing side, on a radial stop pin passing through a longitudinal slot of an intermediate part of the secondary piston extending between the two piston flanges which form the respective pressure-tight displaceable limitation of the secondary outlet-pressure space on the one hand and of the primary outlet-pressure space on the other hand.

Abstract: A hydraulic master cylinder piston carries a circumferential seal ring which allows recuperation flow valving. The floating seal has a reinforcing metal girdle which prevents radial expansion and axial crushing. The seal material resists extrusion and has an outer radius slightly greater than the radius of the circumferential girdle. A forward slotted bearing ring maintains the piston in alignment with the bore. During piston return, recuperation occurs through a path comprising the radial clearance between piston and floating seal ring and at least one slot or groove in the bearing ring. Upon full piston return, the seal is withdrawn from the master cylinder working chamber into a larger diameter bore communicating with the reservoir and thus allows relatively free make-up flow.

Abstract: A mechanical arrangement to provide power assistance for the application of vehicle brakes with a positive shut-off of power assistance immediately upon release of the brake control by the user. The shut-off is achieved mechanically by providing pressure relief from the power assist pressure chamber by connecting a pressure relief channel between the power assist chamber and the brake fluid reservoir or by disconnecting the power piston in the power assist chamber from the main piston as soon as the brake control is released by the user.

Abstract: A portless-type master cylinder for use in an automotive fluid brake system has a supporting means which resiliently supports the end of a piston adjacent to a push rod so as to preserve a predetermined gap between the end of a valve rod and a stopper member when the master cylinder is not operating. With this arrangement, the wasteful stroke is minimized and the impact at the time of start-up of the master cylinder is reduced.

Abstract: A master cylinder of the center feed type including a cylinder defining an axially extending pressure chamber and including a reservoir port proximate the front end of the cylinder for connection with a fluid reservoir; a piston slidably positioned in the cylinder and adapted for coaction with a piston rod extending into the rear end of the cylinder; a valve assembly in the pressure chamber including a valving member proximate the reservoir port and a valve stem secured to the valving member and extending axially rearwardly in the pressure chamber; and a retainer on the front end of the piston.

Abstract: A tandem master cylinder has a housing containing two pressure chambers for connection to separate braking circuits. A pressure piston component forms pistons movable in the pressure chambers to supply fluid under pressure to the circuits. A balance piston has opposed surfaces subject to the pressures respectively in the chambers and is movable, in response to a pressure difference between the chambers, to reduce the pressure difference. Control valves operate in response to brake actuating movement of the piston component normally to isolate the chambers from a fluid supply reservoir, and a disabling device disables the respective control valves individually to prevent pressurization of one of the chambers when actuation of one brake only is required.

Abstract: A brake system for automotive vehicles, comprising a tandem master cylinder (1) and a vacuum brake force booster (2). A pump (34) is connected to the supply chambers (10, 11) of the tandem master cylinder (1), which pump is actuated by an electromotor (35) started by a brake slip control device to replenish, in the brake slip control, the pressure fluid volume discharged from the working chambers (4, 5) of the tandem master brake cylinder (1), by way of the supply chambers (10, 11) and the sleeves of the master cylinder pistons (6, 7). To control the pump pressure, a pressure control valve (36) is provided to the control chamber (37) of which a control pressure is applied, which is generated in a control chamber (23) by a control piston (24) coupled ahead of the tandem master brake cylinder (1). The control chamber (23), by way of a magnetic valve (39), is pressure-relieved when the brake slip control device is turned off.

Abstract: A master cylinder and proportioning valve therefor comprises a housing forming a bore with a piston movable therein and a porportioning valve engageable with the piston to control operaton of the proportioning valve in response to movement of the piston.

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

Abstract: Hydraulic assistance device for brake actuation comprising a body (10) having a bore (12) in which first and second piston mechanisms (34, 56) are slidably mounted, the first piston mechanism (34) being displaceable under the effect of the actuation of a third piston (16) mounted slideably in the bore (12), and the second piston mechanism (56) being displaceable by way of a hydrostatic connection formed in a presure chamber (60) defined between the first and the second piston mechanism (34, 56), there being associated with each piston mechanism (34, 56) a respective valve mechanism (52, 78) in a respective hydraulic circuit between a fluid source under pressure (54, 84) and a respective brake circuit (62,88), and a third chamber (30) defined in the bore (12) between the first piston mechanism (34) and the third piston (16), characterized in that the third chamber (30) is partially delimited by a fourth piston (92) which is displaceable under the effect of the pressure in the third chamber (30) as it meets a f

Abstract: A master cylinder (10, 210, 310, 410) includes a housing bore (14) having at one end (16) a bearing member (18) attached thereto and retaining a sleeve member (20) within the bore (14). One piston (30, 230, 530) has at one end (32, 232) thereof a fast fill mechanism (150, 350, 450). The fast fill mechanism (150, 350, 450) includes a seal support (130, 330, 430), fast fill seal (160, 360, 460), a ramp (132, 332, 432) on the fast fill seal support (130, 330, 430), and a ramp (125, 325, 425, 525) at the one end (32, 232) of the piston. The ramp (125, 325, 425, 525) at the one end (32, 232) of the one piston (30, 230, 530) may be disposed within the piston (230, 530, 441) or on a flange support (120) mounted on the one piston (30).

Abstract: Pneumo-hydraulic converter for disc brake callipers, particularly for commercial vehicles, comprising a body intended for application directly to a brake calliper or in the immediate vicinity thereof and having a central axis cavity in which there is sealingly slidable a first piston to which is fixed a second piston sealingly slidable in a pneumatic chamber formed at one end of the body and connected at one end to a pressurized air supply and containing a biassing spring for the first and second pistons at its opposite end. The first piston is operatively associated with a hydraulic chamber formed at the other end of the body and defined by a hollow slider guided axially within the body and intended to operate the brake calliper, and the hydraulic chamber is connected to a hydraulic fluid reservoir.

Abstract: In this portless type master cylinder device, a cylinder bore is formed in a body thereof, and a piston member is fitted in the cylinder bore and is slidably movable from an initial axial position therein and defines a pressure chamber in cooperation with the cylinder bore. An intake valve communicates between the cylinder chamber and the fluid reservoir via a fluid flow path, and is opened when the piston member is in its initial axial position while it is closed when the piston member moves through more than a determinate relatively small axial distance from its initial axial position.

Abstract: A master cylinder assembly (10) and method for manufacturing the same includes a housing 12 for movably receiving a pair of pistons (32, 34) which cooperate with seals (28, 30) to communicate fluid pressure to respective brake circuits during braking. A reservoir 40 is formed by an integrally molded single unit which also extends into the housing bore (11) to define a liner (46) which substantially positions the seals (28, 30) within the bore (11). A sleeve (26) is also positioned in the bore 11 by the liner (46). When the master cylinder assembly (10) is manufactured the reservoir (40) and liner (46) are formed simultaneously.

Abstract: A hydraulic master cylinder has a piston of cylindrical section slidably sealed within the cylinder bore. An insert is mounted on the piston and defines an axial groove for engagement of an abutment projecting laterally into the cylinder bore, and a transverse slot for retention of a lever which is adapted to engage the abutment to control the opening and closing of a breather valve.

Abstract: In this portless type master cylinder device, a cylinder bore is formed in a body thereof, and a piston member is fitted in the cylinder bore and is slidably movable from an initial axial position therein and defines a pressure chamber on its one side and a reservoir chamber on its other side in cooperation with the cylinder bore. An intake valve communicates between the cylinder chamber and the reservoir chamber, and is opened when the piston member is in its initial axial position while it is closed when the piston member moves through more than a determinate relatively small axial distance from its initial axial position. Intermediately along the fluid flow path between the intake valve and the reservoir chamber, there is provided a means for presenting a relatively high flow resistance to flow of fluid in the direction from the intake valve to the reservoir chamber.

Abstract: The master cylinder (10) comprises a housing (12) having a longitudinal bore (14), a housing end (16) enclosed by a bearing member (18) which retains a sleeve member (20) within the bore (14), a reservoir (70) mounted on the housing (12) and a pair of pistons (30, 40) received slidably within the bore (14), one piston (30) extending through an end (24) of the sleeve member (20). The one piston has an end (32) which provides seating for a fast fill valving mechanism (110). The fast fill valving mechanism (110) comprises a piston support guide (120) supporting a fast fill seal (150) and seal retainer (160) between the support guide (120) and the surface (23) of the sleeve member (20). The seal retainer (160) engages one end (142) of a spring (140), the other spring end (143) located at the end (32) of the piston.

Abstract: A braking pressure generator with a master brake cylinder (2) and a hydraulic brake power booster (1) connected upstream thereof and comprising a piston (16) of larger effective surface which latter is incorporated axially movably within limits in a bore (15) in a stepped piston (10) of smaller effective surface extending through the booster chamber (8). The piston (16) serves to actuate a master cylinder piston (31). During an actuating action the two pistons (10, 16) are maintained in their position moved apart from one another even in the event of pressure drop in the booster chamber or in excess of the point of maximum boosting. This is accomplished in that both pistons (10, 16) enclose a pressure chamber (23) which is connectible to the booster chamber (8) through a valve passage (19) closable by the actuating element (6) of the brake power booster (1) as well as through a non-return valve (25) in parallel relationship thereto.

Abstract: A brake power servo booster in which a power piston is slidably disposed in a shell, a master cylinder is connected to the brake pedal side of the shell, an input shaft is used to actuate a valve mechanism in order to generate a pressure difference between the forward and backward sides of the power piston, an output shaft is used to connect the power piston and a piston contained in the master cylinder, and a stopper member is provided in the housing of the master cylinder for limiting the retreat position of the input shaft.

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

Abstract: The master cylinder (10) comprises a housing (12) having a longitudinal bore (14), an end (24) enclosed by a bearing member (18) which retains a sleeve member (20) within the bore (14), a reservoir (70) mounted on the housing (12) and a pair of pistons (30, 40) slidably received within the bore (14), one piston (30) extending through the end (24) of the sleeve member (20). The one piston (30) has a reduced diameter end (32) which provides seating for a fast fill valving mechanism (110). The fast fill valving mechanism (110) comprises a fast fill seal (120) having a flexible arm (122) engaging an interior surface of the sleeve member (20) and the sleeve member (20) having longitudinal grooves (22) adjacent the arm (122), a fast fill spring member (140) trapped between the fast fill seal (120) and a land member (130), the land member (130) having pockets (132) covered by the fast fill spring member (140) and the pockets (132) communicating with passages (133) in the land member (130).

Abstract: A clutch master cylinder comprises a master cylinder body provided thereon with a fluid reservoir tank and therein with an inlet port in communication with the reservoir tank and an outlet port for connection to a slave cylinder, a piston axially slidably disposed within the cylinder body and arranged to be moved inward by a push-rod, a valve seat arranged between the inlet and outlet ports within the cylinder body to permit fluid flow passing therethrough, a valve body associated with the piston to cooperate with the valve seat in response to inward movement of the piston, a fixed plug mounted on the cylinder body, and an adjusting plug disposed within the cylinder body to adjust an axial space between the valve seat and the valve body, the adjusting plug having an outer end portion adjustably threaded into the fixed plug and fastened in place by a lock nut threaded thereon and being provided at an intermediate portion thereof with an annular flange engageable with the inner end of the fixed plug to restrict

Abstract: A pressure cylinder is disclosed having at least one master cylinder piston, provided with a compensating bore which is in connection with opposite sides of the piston and which is closable by a valve piston movable relative to the master cylinder piston. The valve piston is fastened at the end of an extensible central tension element which projects into the pressure chamber of the pressure cylinder and secures through two spring retainers a piston return spring at the master cylinder piston. In order to reduce the idle travel of the master cylinder, the distance between a stop and an abutment face on a flange of the cylinder is first determined and then added to a predetermined functional distance desired to be maintained between the abutment face and a pressure surface on an actuating piston, so that an assembled dimension is determined. The extensible element is adjusted during assembly to position the pressure surface spaced from the stop equal to the assembled dimension.

Abstract: A piston defines in a cylinder housing a pressure chamber connected to a brake pipe and a fluid supply chamber connected to an oil reservoir. The piston has a recess facing the pressure chamber at one end thereof. A valve member is provided in the recess for making or breaking fluid communication between the pressure chamber and the oil reservoir through the supply chamber. A compression spring is disposed in the recess for urging the valve member into its closed position. A spring retainer is fitted about the end of the piston for holding the spring in the recess. A supporting member is provided in the housing on the opposite side of the pressure chamber from the piston. The valve member is supported by a connecting rod extending axially movably through the spring retainer and the supporting member. A compression spring is connected between the spring retainer and the supporting member for urging the connecting rod in the direction which causes the valve member to open.

Abstract: In a hydraulic dual-circuit brake system for motor vehicles, especially high-powered heavy passenger cars, in which the front wheel brakes combined in a front-axle brake circuit are exposed to higher thermal loads than the rearward brakes, brake fluid is conveyed by means of a feed pump to the outlet-pressure space for cooling the front wheel brakes following a braking phase. Circulated brake fluid flows from the master cylinder outlet pressure space assigned to the front-axle circuit, to the wheel brake cylinders, to an additional functional space of the primary piston in the master cylinder, and back to the supply vessel. The circulating fluid pump is controlled by a timing relay which is tripped by the brake-light switch and remains energized for a predetermined time interval to allow sufficient cooling by fluid circulation.

Abstract: A dual-piston hydraulic brake master cylinder includes a large hydraulic piston which supplies an initial large brake fluid volume and a small hydraulic piston which continues to supply brake fluid to the brakes when the large piston stops moving forward in its cylinder at higher brake pressures. The small, central hydraulic piston is connected to the end of a piston rod extension of a pneumatic booster piston. The large piston surrounds the small piston and opens a reservoir line tilt-valve in the piston retracted position. A passageway between the large and small hydraulic chambers is open in the retracted position to allow communication of braking fluid therebetween. During brake actuation a seal arrangement interrupts this communication. The large and small hydraulic chambers supply the brake circuits through delivery passages.

Abstract: A short hydraulic master cylinder includes a secondary pressure chamber recuperation valve assembly which is mounted in the side of the master cylinder body and incorporates a center valve operable by a lever which engages the rear surface of the front seal support flange of the secondary piston. Thus, the portion of the secondary chamber defined by the master cylinder bore is devoid of all valve and operating linkage components. Recuperation flow to the primary chamber is via a center valve assembly connected by bores to the space between the seals of the secondary piston, and the passage through which the lever extends.

Abstract: A method of attaching a master cylinder (12) to a shell (78) of a vacuum brake booster (14) through a sleeve connecting member (62). The sleeve connecting member (62) has internal threads (64) and external threads (66). The master cylinder (12) has an insert 30 which is screwed into the internal theads (64) and the shell (78) of the booster (14) screwed onto the external threads (66) until the internal components (52, 54, 98 etc.) of the master cylinder (12) and vacuum brake booster (14) are in proper alignment. Thereafter, the master cylinder (12) and shell (78) are held stationary and the sleeve (62) is screwed into the shell (78) to lock the master cylinder (12) and shell (78) in a fixed relationship.

Abstract: A master cylinder (10) having a sleeve (24) for positioning first (22) and second (30) seal members within a bore (14) of the housing (12). The first (22) and second (30) members each have a primary seal (52), a retainer (58) and secondary seals (54 or 55). The primary seals (52) have a base member (60), a peripheral ring (64) and a flexible bellows section (66). The retainers (56) have a groove (70) for holding the base member (60), radial slots (74, 74') connect to a source of fluid and either a rib (100) or projection (94) for positioning the secondary seals (54 or 56). First (38) and second (40) pistons which engage the first (30) and second (22) seal members, have communication passages (80, 82) through which the radial slots (74, 74') (75, 75' ) are connected to first (46) and second (42) chamber.

Abstract: The piston of the generator (6, 8) has a smooth lateral surface and cooperates in sliding sealing engagement with a pair of seals (9a, 9b) fixedly mounted in annular grooves formed in the interior surface of the single bore (2) of the tubular body (1) of the generator. The bore opens at either end of the body and comprises, in its interior surface, at least one longitudinal groove (17) extending over the entire length of the bore, the bore being closed at one end by an obturator element (4) fitted onto the body (1).

Abstract: A master cylinder employed in connection with a fluid actuated motor vehicle clutch system. The master cylinder includes an internal reservoir formed by a portion of the same cylindrical housing which makes up the clutch actuating working chamber. A plug is provided within the cylindrical housing to divide the housing into two sections, a working chamber and a reservoir chamber. The plug further includes a check valve system which permits fluid to flow into and out of the working chamber from the reservoir as the fluid capacity of the associated hydraulic circuit changes. Flow into and out of the reservoir is permitted to occur only when an externally applied load to the master cylinder is released. The reservoir chamber includes a slidable piston and a low spring constant helical spring which biases the reservoir plunger to provide a slight hydrostatic pressure for the fluid contained by the reservoir, thereby preventing the ingestion of air or contaminants.

Abstract: Hydraulic assistance device, comprising a body (10) comprising a bore (12) in which a first piston mechanism and a second piston mechanism (18, 20) are slideably mounted, the first piston mechanism (18) being movable under the effect of the actuation of a third piston (16) slidably mounted in the body (10), and the second piston mechanism (20) being movable by the intermediary of a hydrostatic connection formed in a pressure chamber (22) defined between the first and the second piston mechanism (18, 20), a respective valve mechanism (60, 100) being associated with each piston mechanism (18, 20) in a respective hydraulic circuit between a source of fluid under pressure (52, 96) and a respective braking circuit (74, 110); and a third chamber (36) defined in the bore (12) between the first piston mechanism (18) and the third piston (16), the third chamber (36) being connected to a low pressure reservoir (25) through a passage in which a valve mechanism (42 ) is mounted, characterized in that the device incorpora

Abstract: Fluid actuation device with compensation for wear, particularly for friction clutch mechanisms of the type having a cylinder in which there are placed a first piston resting on a spring and a second piston extended by a declutching control rod, and in which the space between the pistons is filled with an incompressible fluid. The cylinder carries a separation wall between two compartments which house respectively the first and the second pistons. An orifice for communication between said compartments carried by the separation wall is associated with a stopper valve rigidly connected to a membrane that is subjected to a pressure for control and transmission of a thrust force on the cylinder and for driving the control rod.

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

Abstract: A hydraulic brake system with slip control, in particular for automotive vehicles, comprising a master cylinder (2) actuatable by a hydraulic power booster (1), in which brake system valve means (23, 24, 28, 29, 32, 33, 34, 35) are inserted between the master cylinder (2) and the wheel brakes (25, 26, 30, 31), connected to the master cylinder (2) which allow to remove pressure fluid from the wheel brakes (25, 26, 30, 31), while the pressure fluid taken from the wheel brakes (25, 26, 30, 31) can be replenished out of the pressure chamber (10) of the hydraulic power booster (1), wherein the master cylinder piston (5) is designed as a stepped piston and an annular surface (18) of the master cylinder piston (5) remote from the working chamber (16) is adapted to be acted upon by the pressure of the working chamber (16), and wherein the chamber (19) confined by the annular surface (18) is connectible to an unpressurized supply reservoir (11) by way of a travel-responsively controllable valve (51).

Abstract: A dual-circuit master cylinder having hydraulic equalization is disclosed including a casing having two parallel bores and elongated pistons defining two power chambers in the casing connected to wheel brakes, a yoke including two blind bores receiving extending portion of the pistons defining two equalization chambers, an auxiliary piston operatively connected to the yoke, and a brake actuating member defining an auxiliary chamber connected to a supply reservoir via a check valve for supplying equal pressurized fluid to the equalization chambers upon movement of the auxiliary piston and yoke to displace the power pistons.

Abstract: In a tandem master cylinder for a vehicle hydraulic brake system having a push-rod piston designed as stepped piston and an intermediate piston designed as stepped piston both pistons being aligned in a stepped bore of the cylinder housing for the purpose of obtaining a particularly short and compact design. The working cylinder communicates with the connecting bore of the one brake circuit provided in the large-diameter step of the intermediate piston, while the small-diameter step of the intermediate piston fits in the working cylinder formed by the small-diameter step of the stepped bore so that the working cylinder is in communication with the other brake circuit via the connecting bore.

Abstract: A slip control hydraulic brake system for wheel brakes wherein a sliding booster piston and a second piston form a working chamber with hydraulic pressure that acts upon a wheel brake. The booster piston and the brake system housing form two annular chambers, the second annular housing chamber larger than the first, whereby upon actuating travel of the booster piston the first annular housing chamber increases in volume and the second annular housing chamber decreases in volume.

Abstract: An arrangement for supplying pressurized fluid into a user circuit, particularly a master cylinder of a clutch, includes a cylinder housing defining a bore. A cylinder sleeve is slidably accommodated in the bore and bounds an external feeding compartment with the housing, as well as an internal pressure chamber. A piston is received in the pressure chamber for displacement in the axial direction of the arrangement in response to the application of an external force, especially that of a clutch pedal, thereto, to exert pressure on the fluid present in the pressure chamber. The sleeve has a connecting port at its end remote from the point of application of the external force, and the housing has an auxiliary port communicating with an auxiliary reservoir and a supply port which communicates with the user circuit.

Abstract: A master cylinder includes a housing with a pair of pistons movable therein to develop fluid pressure in a pair of pressure chambers. One of the pistons carries a seal assembly in order to provide a fast-fill feature. The seal assembly engages a large diameter section during initial braking and separates therefrom after a predetermined fluid pressure level is reached so that the one piston moves relative to a small diameter section to continue fluid pressure buildup during braking.

Abstract: In a master cylinder assembly separate master cylinders are connected by a common transfer passage through which the pressure spaces of the master cylinders in advance of pistons are in communication when the master cylinders are operated simultaneously, and communication between the pressure spaces is cut off by a transfer valve mechanism when one of the master cylinders is operated on its own. Each piston is guided to slide in its respective bore only by the sliding engagement with the bore of a guide portion of the piston and the guide portion is disposed on the outermost side of a transfer port with which the transfer passage is in communication when the piston is in a retracted position.

Abstract: The piston of an hydraulic master cylinder is guided to slide in portions of a bore in a body on opposite sides of a port in the wall of the body by a guide portion of the piston which is disposed on the outermost side of the port and by a cylindrical, axially extending, guide part at the outer end of a radial flange on a retainer. The retainer is mounted on an extension at the inner end of the piston and forms an abutment for a return spring for the piston.

Abstract: A tandem master cylinder which has a compensating bore in communication with a chamber on the rear side of the master piston. The bore is provided in the front wall of master cylinder piston and is adapted to be closed by means of valve body movable relative to said master cylinder piston. The valve body is provided on the end of a central clamping element interconnecting the two spring retainers of a piston restoring spring of master cylinder piston. The valve body is urged against compensating bore as soon as the piston restoring spring is loaded. In order to maintain a predetermined filling pressure in the chamber behind the master cylinder piston and in the output position of the piston in pressure chamber, the piston restoring spring is supported on a spring retainer that is held through a stop on the cylinder housing.

Abstract: A piston for a cylinder device which is formed of fiber glass strengthened resinous material and includes a concave portion, where a plug may remain, formed on an end thereof. The piston is engageable with a push rod and in particular an end surface of the push rod. The concave portion may be formed on approximately the center portion of the end concave surface of the piston and may be of circular configuration. Correspondingly, the concave portion may be formed on a flat surface of the end surface of the piston.