Abstract: A hydraulic pump for vehicles controllable by handlebars, having an unusually small space requirement, including a reservoir suitable for containing a working fluid having a free surface at the top, a pump body provided with a wall which delimits a cavity, and also freely conveying the fluid from the reservoir to the cavity of the pump body through an opening provided in the wall of the pump body. The opening is provided in a portion of the wall of the pump body at a distance from the top thereof, so that, during the operation of the pump, the free surface of the fluid contained in the reservoir is able to fall below the top without the fluid exposing the opening.

Abstract: A pressure cylinder for a hydraulic actuation device in motor vehicles includes a housing (1) with an internal cylinder (2,3). A piston (6) is displaceable in the internal cylinder for forming a pressure space (12) for a hydraulic fluid. The piston includes a hemispherical socket (10) in an indentation (9). A spring (18) is arranged in the pressure space (12), and a tappet (7) is connected by a transmission part with a hemispherical cap (8). The tappet (7) is in a frictional and swivelable engagement in the socket (10) in an indentation (9) by the force of the spring (18). The piston is a deep-drawn, cup-shaped part and includes a filling piece (13) in the interior of the piston (6). An annular space (15) is disposed at a piston surface (14) facing toward the pressure space (12). The annular space (15) is for receiving the spring (18) in a compressed state when the piston (6) is in a top dead center position.

Abstract: A master cylinder (10) having an axial body (12) with a bore (14) for receving a piston (16, 18), a front seal (26, 28) and a rear seal (30, 32) to delimit a rear supply chamber (34, 38) from a front pressure chamber (36, 40). A supply duct (42, 48) in the body (12) that connects a reservoir to the rear supply chamber (34, 38) has an opening between the front seal (26, 28) and the rear seal (26, 28). The front seal (26, 28) is mounted in a groove (110, 112) of the body (12) and has an interior lip that contacts the piston (16, 18) and lifts off the piston (16, 18) as the piston (16, 18) returns from a position of application to a position of rest to allow hydraulic fluid to be resupply the front pressure chamber (36, 40).

Abstract: A master cylinder having a body with a bore therein delimited by a piston into a work chamber and a supply chamber. The work chamber (16) is connected to wheel brakes, while the supply chamber is connected to a fluid supply, through a supply duct. The piston has a shank retained by a guide ring mounted in the bore and a head bears against a thrust ring in a rest position. A first end of the supply duct is connected to the fluid supply, while a end is connected to the supply chamber. A hydraulic damping arrangement that dampens movement of the piston toward the thrust ring and includes structure for shutting off the second end of the supply duct such that brake fluid flows at a reduced flow rate from the supply chamber to the supply duct through at least one exhaust duct.

Abstract: A master cylinder for a bicycle hydraulic disc brake includes a cylinder having a port in fluid communication with a hydraulic fluid reservoir. The port opens to the cylinder between first and second ends of the cylinder. A piston within the cylinder is movable between a select starting position with the seal between the first end of the cylinder and the port opening with the piston a select distance from the port opening and a pressurized position with the seal between the port opening and the second end of the cylinder. A dead-band adjustment structure is operatively associated with the piston for moving the select starting position to adjust the select distance between the port opening and the seal. A lever is pivotably attached to the housing and is operatively associated with the piston to move the piston between the select starting position and the pressurized position as the lever is pivoted between a rest position and a fully-actuated position.

Abstract: A master cylinder includes a cylinder housing having a cylinder bore, a seal cup disposed inside the cylinder bore, and a piston slidably disposed in the cylinder bore in sliding contact with the seal cup and defining a pressure chamber in cooperation with the housing and the seal cup. The piston includes a connecting passage which fluidly connects the pressure chamber with an atmospheric pressure chamber when the piston is in a retracted position. The seal cup cuts off fluid communication between the pressure chamber and the atmospheric pressure chamber through the connecting passage when the piston moves in its axial direction by a prescribed distance from its retracted position. The connecting passage is a stepped hole having a first end portion with a small diameter which communicates with the pressure chamber and a second end portion with a large diameter which opens onto an outer peripheral surface of the piston.

Abstract: Hydraulic master cylinder for a motor vehicle braking circuit, comprising means for concealing the dead travel of the primary (16) and secondary (44) pistons, these concealing means consisting of additional valve shutters (80) borne by the valve shutters (26, 56) that shut off the axial passages (22, 58) formed in the primary (16) and secondary (44) pistons, these additional valve shutters allowing the pressure in the primary (18) and secondary (52) chambers to increase right from the start of movement of said pistons over their dead travels.

Abstract: The present invention relates to an actuation device for an electrohydraulic brake system of the ‘brake-by-wire’ type which is configured as a tandem master cylinder with a first and a second piston that are respectively biased by a resetting spring in opposition to the actuating direction. The resetting spring associated with the first piston is additionally used as a travel simulator spring which determines the pedal characteristics, and a valve device is provided which closes or opens a hydraulic connection between a pressure chamber accommodating the travel simulator spring and a pressure fluid supply reservoir.

Abstract: The piston of a master cylinder in the power train of a motor vehicle is made, at least in part, of a thermosetting plastic material and cooperates with one or more annular seals to ensure that a source of hydraulic fluid is communicatively connected with the chamber in the housing of the master cylinder when the piston is moved by one or more springs or otherwise in a sense to increase the volume of the chamber. When a pedal or another actuator causes the piston to expel pressurized fluid from the master cylinder into a slave cylinder, the seal or seals cooperates or cooperate with the housing and/or with the piston of the master cylinder to seal the source from the chamber of the master cylinder. The slave cylinder can actuate the friction clutch between the prime mover and the transmission in the power train of the motor vehicle.

Abstract: A master cylinder including a cylinder body having a cylindrical bore and an opening in the circumferential wall for a relief port communicating with the interior of hydraulic reservoir. A piston is slidably inserted into the cylindrical bore to form a hydraulic pressure generating chamber in the cylindrical bore. A cup seal is provided with an inner circumferential lip portion contacting with the piston, an outer circumferential lip portion slidably contacting with the inner circumferential wall of the cylindrical bore, and a base portion connecting the lip portions, which are so arranged as to face to the hydraulic pressure generating chamber. The cup seal cuts the communication between the hydraulic pressure generating chamber and the hydraulic reservoir through the relief port when the top end of the outer circumferential lip portion passes by the relief port.

Abstract: A hydraulic piston and cylinder assembly comprising a casing structure defining a reservoir port, a cylindrical bore, and an internal annular groove opening in the bore and communicating with the reservoir port; a piston slidably mounted in the bore for movement between a rearward retracted position in which the forward end of the piston is positioned proximate but forwardly of the internal groove and a forward extended position in which the forward end of the piston is positioned remotely forwardly of the internal groove, and an annular seal positioned in the internal groove and including an inner annular flexible lip sealingly and resiliently engaging the outer periphery of the piston as the piston moves between its retracted and extended positions.

Abstract: A piston for the variable delimitation of a pressure chamber in a housing of a hydraulic cylinder, in particular a clutch master cylinder for motor vehicles, has a main section on which a running surface is provided for a sealing element on the housing side. The sealing element seals a pressure chamber in an operating position of the piston. The piston also has an after-running device, which, in a normal position of the piston, connects the pressure chamber to an after-running area. The after-running device is made separately from the main section and is connected without play to the main section to form the piston. As a result, a piston that is easy to manufacture is created and which, with reference to the after-running device, has an improved functionality compared with prior art.

Abstract: A master cylinder formed of a forward plastic part snapingly secured to a rearward plastic part. The forward part has a tapered draft angle bore and the rearward part has a purely cylindrical bore aligned with the draft angle bore of the front part and conforming to the diameter of the piston of the cylinder. An annular groove is defined by the parts in surrounding relation to the aligned bores and an annular bearing, having a true cylindrical inner surface corresponding to the diameter of the piston, is positioned in the groove to guide the front end of the piston as the piston moves forwardly into the tapered bore of the forward part.

Abstract: A master cylinder assembly in which the casing defines an annular seal groove defining a forward bore portion forwardly of the annular groove and a rearward bore portion rearwardly of the annular groove. The front end of the piston in the retracted position of the piston is received in the forward bore portion to provide total bearing support for the piston and axial grooves are provided in the forward bore portion to allow recuperative fluid to flow from the associated reservoir and through the axial grooves to the forward bore portion forwardly of the retreating piston.

Abstract: A housing (2) for a master cylinder (1) having a bore (3) in which a piston (4) is slideable to pressurize fluid ahead of a main seal (5) on the piston for the supply of pressurized fluid to an outlet (10). Two inlet openings (7,8) are provided into the bore, a first opening (7) for recuperation of fluid from an associated reservoir to that part (6) of the bore ahead of the main piston seal (5) when the piston is in a retracted position and a second opening (8) placing that portion (11) of the bore between the main piston seal and a second piston seal (9) behind the main seal in permanent communication with the reservoir. The housing also has an external inlet connection (41) formed integrally with the housing. The inlet connection has a free end for direct connection with a conduit (41a) connected with the associated reservoir and having a passage (42) for connection with the conduit which opens into the housing bore at the first (7) and second (8) openings.

Abstract: A master cylinder of the invention supplies a brake fluid from a large diameter pressurizing chamber 56 to a small diameter hydraulic chamber 49 by opening a reverse flow checking opening and closing portion 61 by sliding movement of a stepped piston 16 forwardly, that is, fast fill and when the hydraulic pressure of the large diameter pressurizing chamber 56 rises, a control valve 86 escapes the hydraulic pressure of the large diameter pressurizing chamber 56 to a reservoir 12 to gradually lower in accordance with rise of the hydraulic pressure of the small diameter hydraulic chamber 49, thereby capable of reducing a strange feeling in a pedal feeling caused by sudden pressure release of the large diameter pressuring chamber 56.

Abstract: A brake master cylinder for a vehicle brake system in which the assembling precision of a guide and a cup seal, the structure of a communication conduit, and the structure of a cylinder cap and the guide are improved to thereby improve the performance of the brake master cylinder while also reducing the cost and improving the sealing structure between a body and the cylinder cap to thus reduce the size of the cylinder cap. The brake master cylinder includes the cylinder cap positioned in an internal bore opening portion of the body, a first piston inserted into a cylinder housing through the cylinder cap and slidably supported by the guide in the axial direction, a second piston positioned coaxially with the first piston at the front of the first piston and slidable in the axial direction in the cylinder housing, and a cup seal at the front of the guide for liquid-tightly sealing a first pressure chamber formed between the first piston and the second piston.

Abstract: A hydraulic cylinder has a piston (13) with a seal (21) in sealed sliding contact within a bore (12) to define a working chamber (16) ahead of the piston for the discharge of pressurised fluid from the bore via an outlet (17) when the piston is undertaking working stroke, an inlet (20) is provided into the bore from an associated reservoir to allow connection between the reservoir and the working chamber when the piston is in a fully retracted state for recuperation of fluid from the reservoir to the working chamber. The connection between the reservoir and working chamber is provided via a sleeve (27) in the bore (12) winch includes axially extending grooves (28), the grooves being closed by the piston seal (21) during a working stroke of the cylinder but the ends (30) of the grooves being open when the piston (13) is in a fully retracted condition within the sleeve thus by-passing the piston sleeve to connect the working chamber and reservoir.

Abstract: A master cylinder for vehicle braking systems includes a housing having a central cavity, at least one fluid supply inlet port, at least one pressure outlet port, and a flange at one end thereof. A piston actuation mechanism within the central cavity is moveable between a first position wherein the central cavity is in fluid communication with the fluid supply inlet and a second position where the central cavity is in fluid communication with the pressure outlet. A cup-shaped end cap is fastened to the housing flange in a fluid sealing relationship wherein the cup-shaped end cap receives at least a portion of the piston actuating mechanism therein and further retains the piston actuation mechanism in an operational configuration within the housing.

Abstract: The invention relates to a device (10) comprising a cylinder body (17) in an inner bore hole (22) in which a piston (21, 42) is mounted in such a way that it can slide axially, whereby the cylinder body (17) comprises at least one part in the front of the blind hole (17a) and one center part bearing a sealing joint, whereby both parts are fitted axially and consecutively from front to back and are interfixed in a sealed manner. Said inner bore hole comprises two front and rear sections which are substantially coaxial and concentric and are used to guide the piston (21,42) in an axially sliding manner. The invention is characterized in that both front (62) and rear (60) sections which are used to guide the piston (21,42) in a sliding manner belong to the center part (17B,64) of the cylinder body.

Abstract: A clutch control device (10) comprising a cylinder body (17) and a piston (21, 42) axially sliding in an inner bore (22) of the cylinder body (17) and at least a dynamic seal (59A, 59C) borne by the cylinder body (17, 17B). The cylinder body (17) comprises, axially arranged successively from the front rearwards, a blind front component (17A) comprising a base (24), a central component (17B) and a rear component (17C) open rearwards made of plastic material and assembled together sealed by welding (58A, 58C) with indirect heat input, and the inner bore (22) comprises a front portion (22A) and a rear portion (22C), and the dynamic seal (59A, 59C) is housed in the central component (17b) of the cylinder body (17).

Abstract: A brake handle device for a hydraulic brake assembly includes a barrel received in a housing and having an outer peripheral depression for forming an annular chamber between the barrel and the housing. A plunger is slidably received in the barrel and has an outer peripheral recess for forming an annular space between the plunger and the barrel. The barrel has two apertures for communicating the annular chamber and the annular space. The housing has a cavity for receiving a spring-biased panel and for regulating the oil when the oil is expanded.

Abstract: A master cylinder for braking of reduced size and complexity and a method of making a master cylinder. The master cylinder includes a sub-tank for supplying working oil for braking, the sub-tank being integrally connected to a master cylinder main body. A first port and a second port are formed close to one another in a partition wall separating the master cylinder main body from the sub-tank. The sub-tank has a first opening and a second opening. The axes of the first and second ports in the partition wall pass through the first opening in the sub-tank, which allows tools to be inserted through the first opening to form both ports.

Abstract: A master cylinder having a body (1) pierced with a bore (100) that is partially closed by a guide ring (11). A piston (3) mounted to slide in the guide ring (11) and bore (100) to define a pressure chamber (4) within the bore (100). An inlet (2) having a filling duct (21) which connects the bore (100) with a source of hydraulic fluid having a low pressure when the piston (3) is in a position of rest. The filling duct (21) is located between a flared portion (104) of the bore (100) and a front edge (62) of a ring (6) which slides in the body (1) between the guide ring (11) and pressure chamber (4). The piston (3) and sliding ring (6) have respective a first stop (31) and a second stop (61) which allows the piston (3) to drive the sliding ring (6) along when the piston returns to a position of rest.

Abstract: A fluid injection port 10 is formed in the upper portion of a reservoir 5 at the front side of a vehicle. A first union hole 13 and a second union hole 14 are formed in a bottom wall 6g, and a level detector 15 is provided in a fluid chamber 4. The fluid chamber 4 is divided by partition walls 6i and 6j into a first fluid chamber 4a, a second fluid chamber 4b and a third fluid chamber 4c. The fluid injection port 10 communicates with the first fluid chamber 4a, the first union hole 13 communicates with both the first and the second fluid chambers 4a and 4b, and the second union hole 14 and the level detector 15 are placed in the third fluid chamber 4c. The second fluid chamber 4b and the third fluid chamber 4c communicate with each other via an opening 19.

Abstract: A hydraulic master cylinder for a clutch or brake of a motor vehicle is simultaneously optimized for cost-effective mass production and for functional properties.

Abstract: An object of the present invention is to reduce the work cost of a piston, and to decrease the resistance of flow in a communicating passage between a pressure chamber and a reservoir, and to reduce the ineffective stroke, too, and the means is as flows: a small outside diameter portion (28) whose outside diameter is reduced by forming a step surface (27) on the periphery of a piston (24) and a sleeve (30) to be fitted onto the periphery of the small outside diameter portion (28) are provided; and a radial passage groove (32) formed along the radial direction between the step surface (27) and the end surface of the sleeve (30) opposite to the step surface (27) and an axial passage groove (33) formed along a direction crossing the radial passage groove (32) between the inner surface of the sleeve (30) and the peripheral surface of the small outside diameter portion (28) are provided; and the radial passage groove (32) and the axial passage groove (33) are used as a communicating hole.

Abstract: A master cylinder realizes a stroke simulator function without the need to change the structure around a brake pedal and without impairing brake pedal feel, is easy to form by machining, and also facilitates a hydraulic fluid charging and air bleeding operation. A secondary piston is split to make the axial length thereof variable, thereby imparting the stroke simulator function to the secondary piston. By doing so, brake pedal feel is improved more than by separately adding a stroke simulator.

Abstract: As the primary piston 3 is driven forward, a cup seal 32 moves forwardly of a communication path 17c in a first sleeve 17 to interrupt a communication between a first reservoir chamber 11 and the first liquid pressure chamber 5, thus generating a liquid pressure in the first liquid pressure chamber 5. As the secondary piston 10 is driven forward, a cup seal 25 moves forwardly of a communication path 18c, interrupting a communication between a second reservoir chamber 19 and a second liquid pressure chamber 6, thus generating a liquid pressure in the second liquid pressure chamber 6. The invention provides a master cylinder 1 which is simple in construction and inexpensive to manufacture.

Abstract: The invention concerns a device comprising a shift cylinder with a cylinder body (17) bearing a first sleeve (54) for guiding a second sleeve (42) enclosing an axially mobile piston (21) with an intervening piston seal between the second sleeve (42) and the piston (21) and a secondary seal (59) between the body (17) and the second sleeve (42) penetrating into the hydraulic chamber. The invention is applicable to motor vehicles.

Abstract: A master cylinder includes a cylinder, a piston slidably provided in the cylinder, an annular cup seal held on an inner circumferential surface of the cylinder, and a relief port formed in the piston. The piston and the cylinder define a pressure chamber for generating fluid pressure in front of the piston, and the cylinder and an outer circumferential surface of the piston define a fluid supply chamber which communicates with a reservoir. The cup seal is adapted to slide against the outer circumferential surface of the piston to separate the fluid supply chamber from the pressure chamber. The relief port provides communication between the pressure chamber and the fluid supply chamber. A control taper surface is formed on the outer circumferential surface of the piston rearwardly from the relief port. The control taper surface is tapered toward the front of the piston and is capable of abutting against an inner circumferential surface of the cup seal.

Abstract: An electrically actuated hydraulic power cylinder for use in a vehicle braking system. The power cylinder includes an electric motor, a rotary-to-linear actuator for converting rotary motion of the electric motor to a linear motion, and a hydraulic cylinder. In a preferred embodiment, the rotary-to-linear actuator is a roller screw assembly. The roller screw assembly converts rotational motion generated by the motor into axial movement of a piston which is disposed within the hydraulic cylinder. The movement of the piston pressurizes a volume of fluid. The pressurized fluid flows through an outlet port connected to either a single wheel brake cylinder or a plurality of wheel brake cylinders, thereby actuating the associated wheel cylinder. In a specific embodiment of the invention, the roller screw assembly is incorporated into the internal structure of the motor for compactness and weight reduction.

Abstract: A main object of the present invention is to provide a technique capable of improving the assembling performance of a double seal ring. According to the first embodiment of the invention, on the piston 31 side to which a seal ring is attached, there are provided a ring retaining portion 300 having an outside diameter L0 and for retaining a double seal ring 51, a first land portion 310 adjacent to the ring retaining portion 300 and having an outside diameter L1 (where L1>L0), and a second land portion 320 adjacent to an opposite side of the ring retaining portion 300 to the first land portion 310 and having an outside diameter L2 (where L2<L1). The outside diameter L2 of the second land portion 320 is set to be equal to or smaller than an inside diameter of the outer peripheral resin ring 55, and one side surface of the outer peripheral resin ring 55 on the side of the second land portion 320 is supported by a retainer ring 80 retained by the piston 31.

Abstract: To ensure pressure compensation and the replenishment function of a master cylinder, the present invention discloses the provision of supply channels configured as slits (40). The slits (40) are adequate to ensure pressure compensation and the replenishment action when the brake system is bled. Due to their large cross-section, the slits permit a large fluid flow which is required, for example, to supply the pump in brake systems which independently initiate a braking operation.

Abstract: A boosted braking device having a master cylinder and a pneumatic booster wherein the force for actuating the master cylinder is derived from a combination of an input force and a boost force of the booster. A main hydraulic piston of the master cylinder has a holler cylinder for receiving the input force. A secondary hydraulic piston located within the holler cylinder of the main hydraulic piston receives a hydraulic reaction force to impart an increasing braking force corresponding to an input force applied over an entire travel of a brake pedal.

Abstract: A master cylinder includes a housing and a piston movable therein, which is sealed relative to a pressure chamber by way of a sealing element fixed on the housing. The pressure chamber is connectable to an unpressurized supply chamber by at least one transverse bore provided in the piston, wherein the transverse bore has a slot-shaped configuration and opens into at least one groove provided on the outer surface of the piston.

Abstract: A hydraulic master cylinder having a cylinder body (1) with a piston (3) slidable therein. The piston carries a sealing assembly (20) to permit pressurization of a pressure chamber (6) and fluid recuperation upon retraction of the piston. The sealing assembly includes a first seal (23) of relatively hard material slidable against the internal cylinder wall and a relatively resilient second seal (25) arranged to act between the sealing surfaces of the piston and the first seal to provide a fluid tight pressure seal during pressurization of the chamber.

Abstract: A brake-pressure modulation device in which a hydraulic unit, fitted with solenoid valves, with return pumps, accumulators and dampers of an anti-lock brake system also has a tandem brake master cylinder. The hydraulic unit has a housing with a standard location hole, into which four lip seals identical at least in their outside diameters are inserted. The lip seals hold a primary and a secondary piston of the tandem brake master cylinder. The use of four lip seals with the same outside diameter makes it possible to use the same housing with the standard location hole for different types of vehicle, even when the piston diameter and the operating stroke are changed.

Abstract: A dual acting master cylinder and reservoir assembly includes a pair of bayonets on the reservoir that are received within primary and secondary bosses of the master cylinder. The bayonets each include disks within their central openings wherein each disk has a control orifice for controlling the pressure rise in the associated primary and secondary braking circuits during the initial filling process of the master cylinder and reservoir assembly. Through means of the control orifices, the initial filling process of the braking system through the reservoir is effected while minimizing pressure differential establishment across the secondary piston.

Abstract: A traction control low-restriction check valve for use in a compensating port master cylinder used with a traction control system and an antilock braking system. The check valve is a poppet valve mounted in a primary piston of the master cylinder. The popper valve is resiliently biased in a sealing position but allows brake fluid to be drawn by a traction control pump from a brake fluid reservoir against the resilient bias when the primary piston is not being translated to increase brake fluid pressure within the master cylinder.

Abstract: A brake master cylinder includes a shiftable seal that provides an apparatus for maximizing compensation fluid flow during minimal fluid draw conditions such as occur through automatic traction control brake intervention type operation. The shiftable seal moves forward to compress a low load spring during fluid draw from the master cylinder's high pressure chamber to open a compensation flow path between the seal and the piston.

Abstract: A gear shift device for gear boxes for vehicles, comprising at least one pair of mutually connected, double-acting hydraulic cylinders (1,2), where the pair consists of a master cylinder (1) and a slave cylinder (21). The master cylinder can be operated via a gear lever and the slave cylinder moves a mechanism which is connected to gear selector carriers in the gearbox. According to the invention each end section of the master cylinder's (1) piston (4) has an outer (54 or 55) and an inner (56 or 57) piston sealing ring which are arranged at intervals, calculated in the piston's longitudinal direction, and in these end sections there is provided a drilling (52 or 53) whose first end leads into the piston surface between the respective end sections outer and inner sealing rings (54, 56 and 55, 57 respectively), and whose second ends leads into the adjacent end face of the piston (4).

Abstract: A master cylinder for use in a brake system having an anti-spin apparatus to provide traction control for the drive wheels of a vehicle. The brake system has a pump responsive to an input from the anti-spin apparatus for directly drawing fluid from a reservoir into the brake system through a separate valve located in a pump compensation port connected to a pressurizing chamber of the master cylinder.

Abstract: A master cylinder (1) has a cylinder housing (2) composed of a body (3) having an opening at one end thereof and a cap (4) screwed into the opening of the body; pistons (6, 7) installed movably and guided and supported by a piston (5) and guide sleeve (10) in the cylinder housing; and pressure chambers (8, 9) in the housing in communication with a reservoir (2, 6) via through holes (13, 14) which are closed to cut off communication between the pressure chambers and the reservoir as the pistons move into the pressure chambers during application of the pistons to send under pressure the fluid in the pressure chambers to an operation system. A piston guide section (17) extending in the radial direction is integrally formed on the inner peripheral surface of the cap, and a passage (25) having one end (25a) open on the sliding surface of the piston (6) and the other end (25b) in communication with the reservoir (26) is formed in the cap.

Abstract: A piston arrangement for a master cylinder having a pin for linking a center compensation valve in primary and secondary pistons with a stop members. The primary and secondary each have a pin located in a blind bore which has a cylindrical body with a first semi-spherical head on a first end and a second semi-spherical head located on a second end. A valve return spring acts on a poppet assembly of each compensation valve to position a stem between the first and second semi-spherical heads to hold the pins in the primary and secondary pistons. When a piston return spring moves the primary and secondary pistons toward a rest position, the second semi-spherical heads are held stationary as the pins pivots about the first semi-spherical heads to act on stems and move poppets away from seats and communicate fluid from a source to pressurizing chambers associated with the primary and secondary pistons.

Abstract: An anti-lock-controlled hydraulic brake system is described having a pump (9) and a master brake cylinder (1). An arrangement for controlling the pump pressure is integrated in the master brake cylinder ( 1 ) and consists of the combination of a connection of the pump to the master cylinder and reservoir, and a primary seal (30, 34) cooperating with a compensating hole (36) in the master cylinder wall. The seal (30, 34) consists of an elastic ring (37) lying on the inside and of a slide ring (38) lying on the outside. The necessary communication between the storage reservoir ( 7 ) and the brake circuits, which enables the brake circuits to be resupplied via a non-return valve, is effected via the nonreturn valves (10, 11) of the pump (9). The double seal can be backed by a secondary seal (41) which completely seals the working chamber against leakage flow past the primary ring seal.

Abstract: The invention relates to a master cylinder comprising a body (12) comprising a bore (14) in which slides, in leaktight manner, at least one piston (16, 18) movable between a rest position and at least one working position and defining at least one pressure chamber (20, 22) connected to an application fluid system, the piston (18) having a peripheral groove (44). According to the invention, a finger (42) actuated by an external mechanism (46) is capable of entering the groove (44) so as to lock the piston in one of its positions.

Abstract: In a master cylinder, a communicating passage is formed in a piston guide which is disposed in a cylinder housing so that the communication passage is in communication with the through hole in said piston guide for supplying oil, and an annular spacer is interposed between the annular seal disposed at the side of the piston guide and the piston guide, an annular spacer which has a plurality of projections protruding outward from the external surface at intervals, so that the annular spacer is positioned in the cylinder housing with the projections of the annular spacer abutting the internal surface of the cylinder housing, and an oil passage is formed between the external surface of the annular spacer excluding the projections and the internal surface of the cylinder housing.

Abstract: A master cylinder includes a second piston that is provided with a hollow portion. The hollow portion includes a yoke portion for receiving an end of the second return spring, a cylindrical portion having a diameter that is larger than the diameter of the second return spring, and a tapered portion located at the open end of the hollow portion. The second return spring is disposed within the yoke portion so that the second return spring is coaxially arranged with respect to the second piston. Thus, although the second return spring is capable of moving rapidly to and fro within the hollow portion, the construction of the second piston and the arrangement of the second return spring within the hollow portion of the second piston helps avoid interference between the second piston and the second return spring. Thus, unpleasant noise can be reduced or eliminated. Moreover, small particles that would normally result when the second return spring scratches the second piston are not as likely to arise.

Abstract: A two-stage brake valve includes a stepped valve bore and pressure piston defining a first stage with a large effective area and a second stage with a smaller effective area. The two stages become effective in succession so that, initially the first stage is used to fill a system and then, following a transitional phase, the second stage generates an operating pressure. A relief channel communicates the pressure chamber of the first stage with a reservoir. A relief valve closes the relief channel in response to an excess pressure generated by operation of the second stage.