Abstract: A hydraulic block of a slip regulation system of a hydraulic external force vehicle brake system that has a master brake cylinder bore and forms a master brake cylinder. In order to prevent a hard impact of a master brake cylinder piston on an end stop when the master brake cylinder is released, in particular when there is a sudden release, for example when the driver's foot slips off the brake pedal, the present invention provides a hydraulic return flow damper that is integrated in the master brake cylinder piston.

Abstract: The invention relates to a master cylinder for an actuating device of a clutch or a brake of a motor vehicle, including a cylinder housing having a pressure cylinder section, as well as a piston mounted movable relative to the cylinder housing, wherein the piston is arranged inside the pressure cylinder section in an actuation state in order to control a fluid pressure in a fluidically sealed pressure chamber by a sealing device on the piston side, and is arranged in a pressureless state such that the pressure cylinder section is fluidically connected to a retention system, wherein a seal of the sealing device is configured, and attached to the piston, such that it rests on a seal protection area of a stop element at least in a parking position in the pressureless state; as well as a method for mounting such a master cylinder.

Abstract: The control apparatus includes operating fluid feeding and delivery lines, a pump-brake having a containment body which defines a sliding chamber and a main piston housed sliding inside the chamber, a control element controlling the movement of the main piston which can be operated by an operator, a control device for controlling the motion transmission of a vehicle or of an operating machine including a fixed part and a moving part suitable for cooperating together, wherein the moving part is suitable for moving through the operation of the control element and includes an auxiliary piston moving between a reference position and at least a detection position and mechanically connected to the moving part to move it with respect to the fixed part during its movement between the reference position and the detection position, the auxiliary piston moving towards the detection position through the movement of the main piston.

Abstract: Disclosed is a brake master cylinder configured to sense a variation in magnetic flux in accordance with operation of a piston installed with a magnet, and thus to control activation of brake lamps. The brake master cylinder includes a cylinder body connected to a booster, first and second pistons to reciprocate in the cylinder body, a Hall sensor installed at an outside of the cylinder body, to sense operation of the pistons, for control of activation of brake lamps, a coupling shaft formed at an end of the second piston facing the first piston, and a magnet ring assembly installed at the coupling shaft such that the magnet ring assembly faces the Hall sensor. The magnet ring assembly includes a bushing centrally formed with a fitting hole to receive the coupling shaft, and a ring-shaped magnet fitted around the bushing, to exert magnetic force on the Hall sensor.

Abstract: A primary piston assembly for a master brake cylinder of a braking system of a vehicle, including a first primary piston component having a first piston element to which a driver braking force is transmittable in such a way that a pressure chamber volume of a pressure chamber of a master brake cylinder of the braking system which is fillable with liquid is reducible by moving the first piston element with the aid of the driver braking force, and a second primary piston component having a second piston element to which the first braking assisting force is transmittable in such a way that the pressure chamber volume of the pressure chamber is reducible by moving the second piston element with the aid of the first braking assisting force.

Abstract: A hydraulic-pressure generator including: primary and secondary pistons displaced corresponding to displacement of a brake pedal; a first pressure chamber communicating with a first hollow in the primary piston and generating in brake fluid hydraulic pressure corresponding to the displacement of the primary piston; a second pressure chamber communicating with a second hollow in the secondary piston and generating in the brake fluid hydraulic pressure corresponding to the displacement of the secondary piston; one or more first communication openings formed in a peripheral wall surrounding the first hollow; and second communication openings formed in a peripheral wall surrounding the second hollow. The flow rate of the brake fluid through the one or more first communication openings is different from the flow rate of the brake fluid through the second communication openings.

Abstract: A hydraulic pressure multiplier having a housing, a bore in the housing and an outer piston slidably positioned within the bore. The pressure multiplier also includes an inner piston having a bore therethrough, the inner piston being positioned within a bore within the outer piston. An opening is provided through an end wall of the outer piston, and a mechanism is provided to selectively control hydraulic fluid flow into the bore within the outer piston. Hydraulic fluid first flows through the opening in the outer piston and through the bore through the inner piston to actuate a slave cylinder or a hydraulic piston within a brake. After a threshold pressure is reached within the slave cylinder, the valve closes and the outer piston is caused to move axially, thereby providing an increased hydraulic pressure within the slave cylinder.

Abstract: The invention relates to a system for the hydraulic control (10) of a clutch (12), e.g. a motor vehicle clutch, comprising an upstream master cylinder (14) which is connected to a down-stream slave cylinder (18) by means of a conduit (16). The invention is characterized in that the system comprises a servo cylinder (30) which is disposed in the conduit (16) between the master cylinder (14) and the slave cylinder (18), said servo cylinder comprising at least one servo piston which can be subjected to an assist force produced by a servo device.

Abstract: A hydraulically-operated press-driven tool actuation system includes a press-driven hydraulic power device and/or a hydraulically-powered tool actuator. In the tool actuator, at least two pistons are carried by a housing, and at least one return device is carried by the housing laterally inboard of the pistons. In the power device, a pump includes a piston disposed in a pump cylinder for pressurizing hydraulic fluid therein. An accumulator is in fluid communication with the pump cylinder, and includes a piston disposed in an accumulator cylinder that houses hydraulic fluid on one side of the piston. A body supports the pump and accumulator thereon and is in fluid communication between the pump and accumulator cylinders. The body includes a pressure relief valve downstream of the pump cylinder and upstream of the accumulator cylinder, and a check valve downstream of the accumulator cylinder and upstream of the pump cylinder.

Abstract: A hydraulically-operated press-driven tool actuation system includes a press-driven hydraulic power device and/or a hydraulically-powered tool actuator. In the tool actuator, at least two pistons are carried by a housing, and at least one return device is carried by the housing laterally inboard of the pistons. In the power device, a pump includes a piston disposed in a pump cylinder for pressurizing hydraulic fluid therein. An accumulator is in fluid communication with the pump cylinder, and includes a piston disposed in an accumulator cylinder that houses hydraulic fluid on one side of the piston. A body supports the pump and accumulator thereon and is in fluid communication between the pump and accumulator cylinders. The body includes a pressure relief valve downstream of the pump cylinder and upstream of the accumulator cylinder, and a check valve downstream of the accumulator cylinder and upstream of the pump cylinder.

Abstract: A fuel cell system comprising a plurality of fuel cells combined together to form a fuel cell stack, with the fuel cell stack having an anode side with an inlet for a fuel and an outlet for non-consumed fuel and exhaust gases arising at the anode side as well as a cathode side with an inlet for a gaseous oxidising agent such as air and an outlet for exhaust gases which arise at the cathode side, and a compressor having a compressor inlet and a compressor outlet, the compressor outlet of which is connected to the oxidising agent inlet of the fuel cell stack provided at the cathode side, is characterised in that a gas dynamic pressure wave machine having a driven rotor is provided, with an inlet for exhaust gases arising at the cathode side, an inlet for fresh oxidizing agent, an outlet for oxidising agent compressed by the cathode side exhaust gases and also an outlet for the cathode side exhaust gases being associated with the rotor and with the outlet for the oxidising agent compressed by the cathode side ex

Abstract: A hydraulic system in a motor vehicle for operating a friction clutch is described, including a slave cylinder acting upon a spring plate of the clutch, and a manually or automatically operated master cylinder acting upon the slave cylinder. The hydraulic system includes a two-stage spring device.

Abstract: A master cylinder wherein an input force applied to a bearing assembly pushes and rotates an input piston into a bore of a housing through the engagement between a helical groove on its outer surface and a pin on the housing to act on a primary piston in the bore that supplies pressurized fluid to wheel brakes. A threaded connection that connects the input piston to a primary master cylinder piston has an opposite direction thread from that of the helical groove in the input piston and as a result the input piston moves at a different rate of travel within the bore than the primary piston such that initial movement of the input piston is accentuated in the movement of primary piston and after a predetermined travel of the input piston into the bore, the input piston and primary piston travel in unison to effect a brake application.

Abstract: A pneumatic servomotor for an assisted braking of a motor vehicle having a unidirectional clutch device (56). The clutch device (56) has a coaxial sleeve (58) that slides on a plunger (46), and a substantially ring-shaped key (60) that is arranged with a given clearance around the sleeve (58) and driven by a moving piston (22). When an input force is applied at a determined speed onto a control rod (38) that is integral with the plunger (46), the key (60) rocks and locks a finger (52) that biases the piston (22) with respect to the sleeve (58) in an axial position. The key (60) includes a peg (78) for axial indexing of the locking position of the sleeve (58).

Abstract: A master cylinder is disclosed which is switched from a normal operating mode to a secondary mode when available vacuum is insufficient to operate the booster or at booster run-out. In these circumstances where the normal power assist from the booster is not available, the effective area of the input plunger of the master cylinder is reduced to reduce the manual actuating force required to generate braking pressure, thereby enabling the vehicle operator to more easily generate braking pressure.

Abstract: A master cylinder having variable input/output characteristics includes a cylinder body in which is formed a cylinder bore and a piston fitted in the cylinder bore and movable upon brake operation. The piston is divided into a front portion and a rear portion, with a pressure chamber being defined at the front side of the front portion and an auxiliary chamber being defined at the rear side of the front portion. The auxiliary pressure chamber is located at the same position as the rear portion of the piston. A first changeover valve is provided between the auxiliary pressure chamber and the pressure chamber to establish and interrupt fluid communication between the auxiliary pressure chamber and the pressure chamber.

Abstract: For a hydraulically actuated device a hydraulic power cylinder with an actuator slidably received for reciprocation within the cylinder and a piston slidably received for reciprocation within a sleeve of the actuator and defining a gas chamber on one side of the piston and a hydraulic fluid chamber on the other side of the piston so that the maximum pressure in the hydraulic fluid chamber is limited as a function of the force of compressed gas in the gas chamber acting on the piston. In this way, the maximum system pressure is a function of and substantially corresponds to the pressure of the compressed gas within the gas chamber and acting on the piston. Desirably, the pressure of the compressed gas in the gas chamber can be readily changed to change the maximum hydraulic fluid pressure.

Abstract: A brake system 1 of the invention comprises a brake pedal 2, a booster 3 which boosts the input force applied by the brake pedal 2 and outputs the boosted force, a travel amplifying mechanism 4 which amplifies the travel of an output shaft of the booster 3 and outputs the amplified travel, a master cylinder 5 which develops master cylinder pressure when the output from the travel amplifying mechanism 4 is applied to the master cylinders 5, and wheel cyclinders 6 which develop braking forces when the master cyclinder pressure is introduced into the wheel cyclinders. By the travel amplifying mechanism 4, the travel of the brake pedal 3 in the initial stage of operation is amplified by the travel amplifying mechanism and is then transmitted to the master cylinder 5, whereby the idle stroke of the operating member caused by various idle portions in stroke in the brake system can be effectively shortened.

Abstract: A hybrid brake system for a vehicle propelled at least by a rotating electric motor powered by a storage battery and in communication with at least one ground-engaging wheel. The hybrid brake system includes a vehicle braking control device and an electrical brake system including the electric motor and the battery, the battery providing an electrical load on the motor during times when the vehicle braking control device is actuated. Rotation of the motor during actuation of the vehicle braking control device provides electrical power to the battery, whereby the battery receives an electrical charge. The motor rotation is slowed by the electrical load, whereby the vehicle is braked by the motor. The hybrid brake system also includes a mechanical brake system including a hydraulic cylinder, a piston sealably and slidably disposed therein and partially defining with the cylinder a chamber of variable volume, the pressure of the fluid in the chamber varying with movement of the piston in the cylinder.

Abstract: Hydraulic Brake System with a Device for Active Braking In order to enable a hydraulic brake system which has a self-priming return pump (14) to quickly fill the wheel brakes (5) in an active braking operation, the present invention discloses the provision of a pressure-volume converter (20) on the pressure side of the return pump (14). The converter (20) causes a large pressure fluid volume to be conducted into the brake line (4) to the wheel brake (5) concerned at a small delivery volume of the return pump (14). This is possible because a return pump can generate high pressure and, thus, produce a sufficient amount of force to displace a stepped piston which can then displace a large quantity of pressure fluid. To permit the development of a sufficient back pressure on the pressure side of the return pump (14), a pilot pressure non-return valve (19) is arranged in the pressure line (18) which extends in parallel to the pressure-volume converter (20).

Abstract: The present invention is directed to a hydraulic brake apparatus for applying braking force to each wheel of a vehicle in response to depression of a brake pedal. An auxiliary pressure source is provided for pressurizing the brake fluid in the reservoir to discharge power pressure. A control piston is slidably disposed in a cylinder body ahead of a master piston to be movable in response to movement thereof, so that a regulator chamber is defined ahead of the control piston, and a rear end thereof is exposed to a pressure chamber. A first pressure receiving device is operatively connected with the control piston for applying thereto first counter brake pressure having a first pressure characteristic, with the power pressure received from the auxiliary pressure source, against the hydraulic brake pressure generated in the pressure chamber and applied to the control piston.

Abstract: A tandem master cylinder comprising first and second oil chambers having first and second pistons and first and second springs disposed in each of said respective chambers, the second piston being connected with a hydraulic push rod; a bypass chamber; and two one-way valve means mounted at one side of the bypass tube and in the body of the first piston for establishing one-way oil flow passage from the second chamber to the first chamber and then to the second chamber. The tandem master cylinder allows the braking power increasing ratio between the front wheels and the rear wheels to follow a nonlinear curve for improving braking efficiency.

Abstract: A two-stage pressure cylinder having a work cylinder (17,100) with a work piston (18,108), and piston rod (20,110) for contact with a work piece, in which the work piston is movable, an oil cylinder (56,116) to contain hydraulic fluid (H), an oil piston (58,118) in the oil cylinder, an air cylinder (72,122), an air piston (74,124) in the air cylinder, and an air piston rod (80,126) connected to the air piston and communicating with the hydraulic fluid, and valves allowing hydraulic fluid to pass from the oil cylinder to the work cylinder to operate the work piston, and on a reverse stroke flow being operable to permit return flow of fluid from the work cylinder into the oil cylinder.

Abstract: A hydraulic pressure transmitting apparatus for energizing power cylinders of the kind useful in moving load-carrying platforms on vehicles or the like, being of extremely compact structure on account of a manifold constituted by an end section of a cylinder housing all essential pressure fluid conduits and control valves, as well as connectors for external pressure cylinders being provided with the manifold.

Abstract: The hydraulic booster device for a brake circuit, comprises a body (30) pierced with a bore (32), in which slide coaxially a pusher (25) controlled by a brake pedal and a piston means (34) located between first (5) and second (33) chambers containing a brake fluid, the first chamber (5) receiving at least one spring (51, 52) which loads the pusher (25) and the piston means (34) away from one another, the first (5) and second (33) chambers being connected respectively to sources of fluid under low pressure (11) and under high pressure (13) by valve mechanism (15). An auxiliary chamber (4) of a volume variable as a function of the position of the pusher (25m), made in the bore (32), communicates with the first chamber (5), on the one hand permanently by way of a restriction (6) and on the other hand by an auxiliary valve mechanism (3) allowing communication during an increased in the volume of the auxiliary chamber (4) and preventing it during a reduction of the latter.

Abstract: A hydraulic brake system comprising a master brake cylinder (10), a brake force booster (12) and a filling chamber (38) by means of which in the initial phase of a brake actuation the brake system on relatively short pedal travel is rapidly filled with hydraulic brake fluid up to a predetermined switch-off pressure, the filling chamber (38) being in conductive communication with a primary chamber (22) of the master brake cylinder (10) and connectable to a hydraulic fluid reservoir (62) via a first valve (82) which closes when the brake force booster (12) is functioning and a pressure obtains in the hydraulic fluid below the switch-off pressure and opens when the brake force booster is not functioning, is characterized in that in the connecting conduit (60, 72, 74, 78) between the filling chamber (38) and the primary chamber (22) a second valve (76) is arranged which closes at a pressure in the hydraulic fluid above the switch-off pressure.

Abstract: A fluid pressure actuator according to the invention is suitable for use as a master cylinder for a vehicle brake or clutch system. The actuator includes a housing having a bore extending therethrough and at least a primary piston movably disposed within the bore and extending out of the housing through one end thereof. The other end of the bore is closed by a removable end cap. A pressure chamber is defined within the bore between the end cap and the piston. Preferably a cylindrical cartridge is located within the housing and that cartridge defines the bore with which the piston is in engagement. The cartridge is removable from the housing when the end cap is removed and this facilitates maintenance or repair of the master cylinder. A fast fill seal assembly may be included on the piston and the actuator preferably a double piston and pressure chamber assembly with a secondary piston being located between the primary piston and the end cap.

Abstract: A hydraulic braking system for an automotive vehicle having a power source for generating a hydraulic power pressure, a reservoir, a master cylinder, a regulator and a plurality of wheel brake cylinders for braking respective road wheels, which are divided into a first group of wheel brake cylinders communicated with the master cylinder and a second group of wheel brake cylinders communicated with the regulator. The regulator has a housing defining therein a regulator chamber for introducing the hydraulic power pressure thereinto from the power source and regulating the hydraulic power pressure into a regulated hydraulic pressure in response to the hydraulic braking pressure generated in the master cylinder, and which is positioned in substantially coaxial relationship with the master cylinder and responsive mechanically to depression of a brake pedal.

Abstract: For attaining an abrupt change in ratio, in a slip-controlled brake system for automotive vehicles, the chamber (11) of a fast-fill cylinder (4) is connected to a plunger chamber (41) of the braking pressure generator (1) which is acted upon by the booster piston (40), while the pressure line (7) leading from the plunger chamber (41) to the fast-fill cylinder (4) contains a pressure-controlled directional control valve (8) governing a pressure-fluid conduit to the pressure-supply reservoir (31). The annular chamber (50) of the fast-fill cylinder (4) is connected by way of a return line (55) to the pressure-supply reservoir (31) and with the prechamber (18) of the master cylinder (15) by way of a pressure line (56), while a pressure-controlled two-way/two-position directional control valve (9) with a non-return valve connected in parallel thereto is arranged in the return line (55).

Abstract: A hydraulic power booster, for the actuation of a master cylinder in an automotive vehicle brake system, in which a booster piston and a brake valve are essentially arranged in parallel with the booster piston. In dependence on the actuation force applied to the brake system, a hydraulic pressure may be developed in a booster chamber which is essentially defined by a pedal-operable piston rod and by the booster piston. In order to supply at least the required absorption volume to the brake actuating devices without considerable reaction force at the brake pedal, the piston rod may be supported at the booster housing, against an actuating force. The booster piston is positively connected with the piston rod so as to enable a limited relative displacement between the booster piston and the piston rod.

Abstract: An improved quick fill type master cylinder having a structure in which a piston consisting of a smaller diameter piston portion and a larger diameter piston portion is slidably fitted into a stepped cylinder bore to define a hydraulic pressure chamber as well as a hydraulic oil supply chamber therein, a relief port opening to the hydraulic pressure chamber and a supply port opening to the hydraulic oil supply chamber are placed in communication with an oil reservoir via a hydraulic oil flow passage formed longitudinally in a cylinder casing, and a valve device is incorporated in the hydraulic oil flow passage. The hydraulic oil flow passage is formed by drilling and the like from the rear end face of the cylinder casing and a valve chamber of the valve device is provided in the oil flow passage near outside opening thereof.

Abstract: A vehicle hydraulic brake system with slip control, wherein a master cylinder (2) is pressurizable by a hydraulic poser booster (1). Valve means (23, 24, 29, 28, 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 valve means serve to remove pressure fluid from the wheel brakes (30, 31, 25, 26). Pressure fluid taken from the wheel brakes is replenished out of the pressure chamber (10) of the hydraulic power booster (1). A stroke limitation of the brake pedal (8) is effected during slip control. To simplify the design of the braking pressure generator (1, 2), the end surface of the master cylinder piston (5) close to the working chamber (16) is larger than the effective surface of the booster piston (4), and that a stepped piston is employed as master cylinder piston (5), an annular surface of said master cylinder piston (5) being adapted to be acted upon by the pressure prevailing in the working chamber (16).

Abstract: A hydraulic vehicle servo brake comprises a master cylinder (11) accommodating at least one stepped main-piston assembly (12). A booster piston (12') is provided which is acted upon by a controlled pressure with the controlled pressure being delivered by a brake valve (29) governed by the brake pedal. When the brake pedal (13) is not depressed, a valve contained in an annular chamber is opened and connects the annular chamber to the supply reservoir. In the event of slight advance movement of the main-piston assembly (12), the valve (20) will close. In this case, a wheel-slip brake control unit will shut off the annular chamber (19) hydraulically towards the outside. To accomplish a compact design, the booster piston (12') and the tapered main piston part (12") are united to form an integral piston (26) of constant diameter.

Abstract: The present invention relates to a hydraulic power booster, in particular for the actuation of a master cylinder in an automotive vehicle brake system, wherein there is a booster piston and a brake valve arranged essentially in parallel to the booster piston. In response to an actuating force applied to on a brake pedal, pressure fluid is adapted to be metered into a booster chamber of the hydraulic power booster, the booster chamber being confined by a pedal-operable rod and by the booster piston. In the presence of relatively small actuating forces at the brake pedal, the wheel brakes connected to the working chamber of the master cylinder are supplied with at least the absorption volume required. The booster piston has a projection at the end remote from the pedal extending into a blind-end bore of a master cylinder piston. A hydraulic connection between the blind-end bore and the booster chamber is adapted to be closed by a pedal-operable valve assembly.

Abstract: A pedal-operated booster incorporates a valve mechanism for controlling pressurization of a boost chamber. The valve mechanism comprises a pedal-operated piston and a pressure-responsive valve spool which is coupled to the piston for limited relative movement in a longitudinal direction within a working chamber in the piston. The spool is movable with the piston in an initial brake-applying direction in which the spool is operative to isolate the boost chamber from an exhaust port and the piston is operative to place an inlet port in communication with the working chamber. This causes the spool to move relatively away from the piston in response to pressure fluid in the working chamber which is admitted to the boost chamber.

Abstract: A dual power brake booster assembly in which the hydraulic boost section is initially operated, the vacuum booster section is then operated to runout while the hydraulic section maintains a hydraulic boosted force level, the hydraulic section is then further operated to further increase the hydraulic boosted force as the vacuum booster section maintains the vacuum boosted force level attained by it at runout, and additional master cylinder actuation by additional manual force. The invention also includes the method of generating brake actuating pressure. The brake booster assembly may be operated only to the extent necessary to produce the desired amount of master cylinder actuation. The booster assembly will operate when the power source for one section is diminished or not available. It is also operable manually when pressure from neither power source is available.

Abstract: A differential master cylinder adapted for use as fluid pressure generating source in a brake system comprises a cylinder body having a stepped cylinder formed therein; a stepped piston arranged to be slidable within the stepped cylinder; a first chamber defined by the end of a portion of smaller diameter of the stepped piston and a portion of smaller diameter of the stepped cylinder; a second chamber defined by the stepped piston and a portion of larger diameter of the stepped cylinder; a first fluid passage provided at the stepped piston and arranged to have the first and second chambers intercommunicate; a check valve arranged in the first fluid passage to close when fluid pressure within the second chamber reaches a first setting value; and a relief valve arranged to open to return the fluid from the second chamber to a reservoir when the fluid pressure within the second chamber reaches a second setting value which is higher than the first value.

Abstract: A master cylinder includes a sleeve (31) which defines fixed positions for a pair of seals (30, 32). A pair of pistons (36, 38) cooperate with the seals (30, 32) to form pressure chambers (40, 42) which communicate fluid pressure to brake circuits during braking. A bearing member (44) cooperates with one (36) of the pistons to define an auxiliary pressure chamber (50) and the bearing member (44) is provided with an additional passage (140) for communicating fluid into and out of the auxiliary pressure chamber as well as an end (46) directing movement of the one piston (36).

Abstract: The present invention is an improved hydraulic booster in which there is a ratio chamber between a power piston and a slave piston. The ratio chamber communicates with a low pressure fluid source through a check means which allows fluid from the low pressure fluid source to flow into the ratio chamber and prevents higher pressure fluid in the ratio chamber from flowing to the low pressure source. The check means can also be modified to allow air to be bled from the low pressure chamber.

Abstract: The object of the invention is a synchronized hydropneumatic control of clutch and gearbox.In accordance with the invention a hydropneumatic servomotor clutch control has been provided which includes a jack the piston of which is assisted by a pneumatic motor and a master cylinder which feeds the said jack with hydraulic fluid and controls the feed of air to the said motor, characterized in that the control chamber of the said jack is connected to the hydraulic circuit for locking/unlocking the gearbox, the feed to the said circuit being carried out through a valve mounted in the piston. The admission of the hydraulic fluid from the master cylinder having as its effect during a first period the closing of the said valve, thus interrupting the admission of fluid into the said chamber, then the causing of the transfer of the fluid contained in the latter towards the circuit for the gearbox which becomes unlocked in synchronism with the clutch.Application to controls of clutch and gearbox of vehicles.

Abstract: A two-stage master cylinder includes a housing with a stepped bore for receiving at least one piston. The one piston cooperates with the housing to substantially define a primary chamber communicating with a brake circuit and an auxiliary or fast- fill chamber. The auxiliary chamber is contracted during a braking application to communicate pressurized fluid to the primary chamber. A valve member is exposed to the fluid pressure within the primary chamber and the auxiliary chamber to communicate the latter with a reservoir. The valve member defines a first differential area and a second differential area which cooperate with the primary and auxiliary chambers, respectively, to meter the communication of fluid from the auxiliary chamber to the reservoir as the fluid pressure within the primary chamber is increasing.

Abstract: A twin-piston (e.g. tandem) master cylinder is provided for a split braking system having disc brakes on some wheels of a vehicle and drum brakes on others. A delay valve is incorporated in the master cylinder for the supply to the disc brakes, the delay valve having a valve member controlled by one of the master cylinder pistons to initially shut-off the supply of fluid to the disc brakes after the piston has moved a short distance. A plunger moves against a control spring to re-open the supply to the disc brakes above a predetermined pressure.

Abstract: An apparatus for controlling hydraulic pressure delivered to brake cylinders for rear wheels of a motor vehicle in dependence on load states and deceleration thereof comprises a first hydraulic chamber communicated with a master brake cylinder operable by a brake pedal, a second hydraulic chamber communicated with the brake cylinders for the rear wheels, a communication passage for communicating the first and second hydraulic chambers with each other, a ball valve disposed in the first hydraulic chamber and adapted to be displaced under inertia to close the communication passage, and a differential piston having pressure receiving regions exposed in the first and second hydraulic chambers for controlling the rate of increase in the hydraulic pressure within the brake cylinders for the rear wheels relative to the increase in the hydraulic pressure within the master cylinder.

Abstract: A two stage master cylinder having a bore with a first diameter and a second diameter separated by a shoulder. A first piston is located in the first diameter of the bore to establish a first chamber. A second piston has a first section located in the first diameter of the bore to establish a second chamber and a second section located in the second diameter of the bore to establish an actuation chamber therein. A first passage in the second piston connects the actuation chamber with the second chamber. A second passage in the second piston connects the first passage to a reservoir in the housing. A shuttle piston located in the first passage has a first surface area exposed to the second chamber and a second smaller surface area exposed to the actuation chamber. A spring urges the shuttle piston toward the second chamber. An input force from an operator moves the second piston causing fluid to flow from the actuation chamber through the first passage to the second chamber.

Abstract: A master cylinder of the dual pressurizing chamber type for pressurizing brake fluid in separate brake actuating circuits has the primary piston reciprocably mounted in a stepped bore so that the piston rear land moves within a larger bore section than does the piston front land. The secondary piston moves in the same bore section as does the primary piston front land, and has a pair of spaced lands with oppositely facing lip seals. The front land of the primary piston is also provided with a lip seal. These seals operate to permit the build-up of pressure in the pressurizing chambers located on either side of the secondary piston, while permitting fluid to flow past the seals into the pressurizing chambers when the chambers adjacent the pressurizing chambers are producing a greater pressure than that being produced in the pressurizing chambers.

Abstract: A brake force booster installation with a mechanical, pneumatic or hydraulic actuating mechanism acting on a servo- and adjusting-unit, which in turn acts on the master cylinder, with filling devices and with control- and shifting-devices; the filling devices and the actuating mechanism are thereby actuated by movement of the brake pedal lever pivotally connected at two connecting points to the piston rods of an actuating piston and of a filling piston while the filling devices and the actuating devices are so arranged separated from one another and are so connected with the control and shifting devices that the brake pedal lever during its idle path is actuated with one lever ratio by holding fast one piston rod and thereupon the working effect is realized by automatically shifting to a different translation ratio.

Abstract: Apparatus for transferring gas from a first container to a second container of higher pressure comprising a free-piston compressor having a driving piston and cylinder, a smaller diameter driven piston and cylinder, and a rod member connecting the driving and driven pistons for mutual reciprocation in their respective cylinders. A conduit may be provided for supplying gas to the driven cylinder from the first container. Also provided is control apparatus for intermittently introducing gas to the driving piston, from the first container, to compress gas by the driven piston for transfer to the second higher pressure container.

Abstract: The invention relates to a hydraulic servomotor comprising a housing provided with a bore slidably receiving two pistons separating an actuating chamber from an utilization chamber, said pistons including an annular outer piston and an inner piston received within the annular piston. Releasable coupling means are provided between both pistons to permit said pistons to move in unison when high pressure fluid is available in the actuating chamber and to permit the inner piston to be moved alone by the push rod in the event of a high pressure failure in the actuating chamber. The motion of the outer piston towards the interior of the actuating chamber is limited by an abutment fixed to the housing.

Abstract: A hydraulic transmission is provided between the booster piston and the master cylinder piston which is automatically interrupted if the booster power is not present. In this arrangement, when booster power is not present, a sufficient pressure can be generated with brake pedal effort alone, making use of the full permissible pedal travel.

Abstract: The invention relates to a master-cylinder having a two-part cylinder, one part being of narrower diameter than the other, and a two-part piston slidable in the cylinder. Two pressure chambers are defined by the cylinder and the piston. Advance of the piston reduces the volume of both. One, the high pressure chamber feeds an external pressure system, and is itself fed by the other chamber through a valve system during an initial phase of the piston stroke. In a later phase the feed from the second in the first chamber ceases and instead the second chamber feeds the fluid reservoir through a control valve. Pressure-transmitting means such as a rod is arranged between the high pressure chamber and the control valve to open the control valve when the pressure in the high pressure chamber exceeds a predetermined value.