Abstract: For the control of a brake-slip controlled brake system the brake pedal force assisted by auxiliary force is transmitted onto a master cylinder (10, 10', 33) and from said onto the wheel brake cylinders via several pressure fluid paths that are adapted to be closed independently of one another. The wheel rotational behavior and the vehicle velocity will be measured with sensors (S1 through S4), the signals will be logically combined, and therefrom control signals will be generated for electromagnetically actuatable directional control valves (15, 16, 17, 19, 35, 36, 37, 42, 43, 52). During control action, the pedal force (F) that is directed to the master cylinder and assisted by auxiliary force will be compensated temporarily by an opposed force, as a result whereof the pressure rise in the master cylinder will be retarded or pressure will even be decreased.

Abstract: A hydraulic vehicle brake system of the type having a high system return pressure is provided. In order to minimize the size and strength of brake return springs required, the invention provides a device to be interposed between the brake and the brake control valve. Preferred embodiments of the device include an inlet port communicating with a brake valve and an outlet port communicating fluid pressure to a vehicle brake. A control assembly is provided intermediate the inlet and outlet ports and includes mechanisms for amplifying the hydraulic pressure effect in the direction from the outlet port to the return pressure system so that the brake return pressure exerted by the brake return springs can be substantially less than the hydraulic system return pressure.

Abstract: A proportioning valve assembly (10) in a housing (12) is pressure responsive to control the flow of fluid to a wheel brake cylinder. The proportioning valve (20) is connected to a channel (31) opening into a reservoir or fluid-containing chamber (13), a second valve (34) being disposed in the channel (31) and engaging at one end an inertia sensitive ball (40) located on a variable slope surface (17), and engaging a third valve (35) at the other end. The proportioning valve (20) includes a second piston (80) having a reduced diameter end (82) engaging a third piston (105) of enlarged diameter disposed in a portion of the channel (31), the channel (31) communicating by an opening (90) with the fluid-containing chamber (13). During initial brake application by the operator, the third valve (35) remains closed so that the third piston (105) does not move and prevents further movement of the second piston (80), thereby preventing higher braking pressure from being communicated to the wheel brake cylinder.

Abstract: A master cylinder-reducing valve assembly has a master cylinder and a reducing valve for transmitting output hydraulic pressure from the master cylinder to a rear wheel brake at a reduced level. The reducing valve includes a valve housing provided on the master cylinder and having an inlet communicating with the output port of the master cylinder and an outlet communicating with a rear wheel brake. A pressure receiving piston is slidably received in the valve housing to divide the interior of the housing into an input hydraulic chamber communicating with the inlet and an output hydraulic chamber communicating with the outlet. The pressure receiving piston has a communication bore connecting between the input and output hydraulic chambers. A valve member is disposed in the input hydraulic chamber to open and close the communication bore. A valve spring is received in the valve housing and biases the valve member toward the pressure receiving piston.

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 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 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: A brake system comprises a tandem master cylinder (24) with working pistons (19, 27), each of which confining a working chamber (25, 29). Upstream of the tandem master cylinder (24) a power booster (1) is connected which is connected to an auxiliary energy source (8) for the pressure supply. Connected to the booster chamber (3) are valves (22, 23) which are controllable by the pressure of the booster chamber (3) and by which a pressure medium communication may be established from the auxiliary energy source (8) to the working chambers (25, 29) of the tandem master cylinder (24) and a dynamic inflow of pressure medium takes place.

Abstract: The device incorporates an actuating piston (6) in tandem with a master cylinder piston (7) both defining first (8) and second (9) braking pressure chambers. A valve mechanism (34), in line with the control valve mechanism (12) of the device, is controlled by a mode selector piston (31) exposed to the actuating pressure coming from the source of fluid under pressure (25) so as normally to isolate the first chamber (8) of the braking circuit (I) joined to the working chamber (5). In the case of failure of the pressure source, the braking circuit (I) is joined to the primary chamber (8).

Abstract: A hydraulic brake booster including main cylinders operative relative to a pedal stroke by which a sufficient pedal stroke is still available in the event of a failure in the pressure supply so that the brakes can be actuated by the pedal stroke and furthermore flooring of the brake pedal is avoided in the event of failure of the fluid medium power supply.

Abstract: A main brake cylinder for vehicle brake systems, in which a control valve effects the application of an auxiliary force to at least one brake piston. Additionally engaging the control valve and supplementarily for possibly adjusting the brake pedal is an arbitrarily actuatable final control element, which is triggered by electrical signals of any desired form and duration. As a result, a feeding of pressure into the brake circuit is effected independently of the brake pedal actuation and as a function of electrical control signals, as a result of which a multiplicity of further possible applications of such a brake valve are afforded, for instance in order to realize a drive slippage regulation, self-diagnosis as to tightness, function, output and pressure supply, and stepped braking.

Abstract: An actuating device for a vehicle hydraulic brake system of the type having electromagnetically operated valves in the hydraulic circuits to each wheel brake for providing slip control wherein the device includes a master cylinder having a brake pedal force responsive hydraulic booster piston for actuating a master cylinder piston slidably mounted within a slidable positioning sleeve within the bore of the master cylinder. The positioning sleeve is adapted to be mechanically coupled to the booster piston in the brake actuation direction. A stationary projection on the interior end of the master cylinder protrudes into the positioning sleeve and cooperates with the sleeve and master cylinder piston to vary the master cylinder volume.

Abstract: A proportioning valve (10, 110) in a master cylinder housing (12, 112) is pressure responsive to control the flow of fluid to a wheel brake cylinder. The proportioning valve (10, 110) is connected to a fluid channel (31, 131) opening into the master cylinder reservoir (13, 113), a second valve (34, 134) being disposed at the opening (32, 132) and being engaged by an inertia sensitive ball (40, 140) located on a ramp (17, 117). The ball (40, 140) is responsive to deceleration of the vehicle whereby the ball (40, 140) moves up the ramp (17, 117) and permits the second valve (34, 134) to close. Closure of the second valve (34, 134) prevents fluid communication between the fluid reservoir (13, 113) and the proportioning valve (10, 110) in order to vary the outlet pressure (P.sub.Out) of the proportioning valve (10, 110) in response to deceleration of the vehicle. The proportioning valve (10, 110) may be contained completely within the housing (12, 112) of the master cylinder (10, 110).

Abstract: This invention relates to a hydraulic brake system for automotive vehicle with a master cylinder (2) and with a hydraulic power booster (1) connected upstream of the master cylinder (2) and having a pressure chamber (4) in which an auxiliary pressure depending on the actuating force (F) may be modulated via a pedal-operable brake valve (7). Wheel brakes (51, 53) of a first brake circuit are connected at the pressure chamber (4), wheel brakes (50, 52) of a second brake circuit being connected at the master cylinder (2). The braking pressure active in the wheel brakes (50 through 53) is controllable by valve members (39, 54 through 59) controllable in dependence on the slip. In case of control, a hydraulic communication will be established between the pressure chamber (4) of a hydraulic power booster (1) and the master cylinder.

Abstract: The present invention relates to a device for actuating an automatic device comprising a plurality of combined mobile members, wherein this device comprises an electric motor actuating a hydraulic master jack which in turn actuates a plurality of hydraulic slave jacks connected to said mobile members.

Abstract: The present invention relates to a dual-circuit hydraulic brake system with slip control, in particular for automotive vehicles, wherein wheel brakes (26, 27, 41, 42) are connected via electromagnetically actuatable multiple-position valves (38, 39, 88, 40, 24, 89) to brake circuits which are hydraulically isolated from one another, wherein the brake circuits are adapted to be pressurized by a tandem master cylinder (1), on the one hand, and are connectible to a dual-circuit pump aggregate (76, 77) adapted to be driven electromotively, on the other hand. Both outlets of the pump aggregate (76, 77) are connected to normally closed brake valves (43, 44) which are governed by the master cylinder pressure and separating valves (11, 12) which are adapted to be closed by the outlet pressure of the brake valves (43, 44) are inserted into the connections between the tandem master cylinder (1) and the wheel brakes (26, 27, 41, 42).

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 brake system for a vehicle comprises a booster unit including a power piston disposed slidably in a housing for defining a first chamber and a second chamber in the housing, a regulator disposed slidably in the power piston, a flow restrictor formed between the first chamber and a fluid pressure source for restricting flow of fluid in response to movement of the regulator, a pilot pressure chamber disposed upstream of the flow restrictor, a movable member moved by the internal pressure of the pilot pressure chamber thereby permitting communication between the second chamber and the fluid pressure source, and a reaction spring disposed between the power piston and the regulator. A master cylinder is connected to the power piston of the booster unit to supply braking hydraulic fluid at controlled pressure to front and rear brakes, and a brake pedal actuates the regulator of the booster unit to cause movement of the regulator relative to the power piston.

Abstract: A power valve for a vehicle braking system includes a main pressure chamber (4) defined between the body (1) and spool (2) and connected to the outlet (5), the spool being displaceable under an input effort to close communication between the chamber (4) and a reservoir port (8) and open communication of the chamber (4) with an inlet (7), and an auxiliary chamber (10) to which fluid pressure may be supplied through a port (11) to exert a force on the spool for reducing the pressure supplied to the outlet (5) for a given input effort applied to the spool (2).

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 wheel cylinder assembly has telescoping brake actuating pistons with a brake pressure proportioner in the larger actuating piston to proportion brake actuating pressure.

Abstract: A pair of tandem master cylinders have primary pressure spaces connected to the brakes on one pair of wheels on opposite sides of the vehicle, and an actuator for the brakes on a trailer is supplied with fluid under pressure from pipe-lines connected to each of the four pressure spaces and under the control of first and second disabler valves. Each disabler valve has a pair of inlet ports, each connected either to respective primary pressure spaces or respective secondary pressure spaces, and an outlet port connected to the actuator. When one master cylinder is operated on its own both disabler valves are closed to prevent the actuator from being operated. Failure of one pressure space, when both master cylinders are operated simultaneously, causes the corresponding disabler valve to close but the actuator can still be operated from the operative pressure spaces, through the other disabler valve.

Abstract: An arrangement for controlling the admission of a hydraulic fluid to respective wheel brake actuating cylinders either from an auxiliary pressure source or from a master cylinder includes a pressure limiting valve and a hydraulically operatable switching valve including a valve body movable only when the auxiliary pressure source is fully operational from a first position in which it connects the master cylinder with the actuating cylinders to a second position in which it connects the auxiliary pressure source with the actuating cylinders and the master cylinder with the pressure limiting valve. The limiting pressure of the pressure limiting valve is adjusted in dependence on the brake pedal travel. The respective master cylinder piston carries a deflectable seal which permits fluid to flow past it in one direction but not in the opposite direction. The pressure at which the switching valve member moves into its second position has a predetermined level, preferably 1 to 2 bar gauge.

Abstract: An improved pneumatic-hydraulic driving device for the knockout mechanism associated with the slide of a press-machine wherein the device serves to actuate the knockout mechanism in a controlled manner to provide cushioning motion during punching of the work, and knocking out motion after punching to permit removal of the punched work by a transfer machine, with the device being particularly useful in the fabrication of printed circuit plates wherein the device serves to decrease cycle-time of fabrication and increase quantity of production.

Abstract: A shortened master-cylinder comprising longitudinal grooves on the inner surface of the bore of the cylinder and provided to allow permanent communication between a fluid pressure chamber and the corresponding fluid output.

Abstract: A hand held manually operable hydraulic auxiliary device for lifting or pressing of loads or for operating of tools includes a hydraulic cylinder having pressure and activating pistons disposed between which is a valve housing including inlet and discharge channels and being furnished with non-return valves.The hydraulic cylinder including both the actuating piston operable by a manually operated lever, and the pressure piston, as well as the valve housing are disposed within an outer casing receiving the hydraulic fluid. The outer casing at least on the pressure piston side thereof is provided with a tool adapter. The valve members include a forced reset guide. Disposed in the area of the pressure side of the hydraulic cylinder is a randomly operable detent.

Abstract: This mechanism makes it possible to obtain in succession a fast approach stroke (C), and then a work stroke with a substantial developed stress, in operations such as riveting or marking, the work stroke being started as the tool (16) comes into contact with the part to be pressed (25). A control stem (4) and a body (9) are movable along one and the same axis (3), means such as a clack (31) providing for their non permanent locking. The stem (4) is integral with a primary piston (8) penetrating into a hydraulic circuit (10, 11) of the body (9); this circuit communicates, on the one hand, with an expansible casing (19) surrounding the body (9) and making it possible to block this body with respect to the frame (1), and on the other hand, with a chamber (12) in which a secondary piston (15), drawn back by a spring (18) and integral with tool (16), slides.

Abstract: A fast-fill master cylinder with integral proportioning includes a housing with a stepped bore defining a large diameter and a small diameter. A piston is disposed with the large diameter and the small diameter to form a fast-fill chamber in the large diameter and a pressure chamber in the small diameter. A passage extends between the fast-fill chamber and an outlet port to bypass the pressure chamber.

Abstract: A combination air brake cylinder and hydraulic slack adjuster for a railroad car brake system includes an air operated piston positioned within a housing. There is an air port in the housing in communication with the air piston and there is a return spring in the housing operable upon the air piston. The housing includes a fluid outlet port and a fluid piston and valve arrangement within the housing connected to the air piston and responsive to brake application movement thereof to supply a brake shoe application fluid pressure at said outlet. A fluid reservoir is associated wtih the fluid piston and valve arrangement and has check valve controlled connecting passages thereto for adjusting slack in the brake rigging during brake application functions.

Abstract: In a vehicle braking system of the kind in which brakes mounted on opposite sides of the vehicle are associated with respective pedals (1) and can be operated together for normal vehicle retardation or independently to assist vehicle steering, the brakes are connected to respective chambers (14, 15) of a tandem master cylinder (5) through respective control devices (7) which are actuated by the pedals (1) and control communication between the respective chambers (14, 15) and a reservoir.

Abstract: Modular proportioners such as those of U.S. Pat. No. 4,213,655 are machined and separated into parts provided with appropriate O-ring seals so that the proportioners may be installed in an auxiliary bore of the master cylinder body. Threaded proportioner connections are eliminated. The proportioner parts are assembled by dropping them in place, in order, in the bore. They are retained in place by a retaining ring. This eliminates threaded connections and is adapted for automatic assembly.

Abstract: A master cylinder assembly comprising two separate master cylinders is disclosed. Pressure spaces of the master cylinders are interconnected through outlet passages and a transfer passage, and a transfer valve is housed within each outlet passage. When the master cylinders are inoperative both transfer valves are retained by yieldable spacers in intermediate positions in which a limited flow can take place through both valves in both directions. This prevents hydraulic fluid from being trapped in the transfer passage which otherwise might cause a fracture to occur upon expansion with temperature of the fluid. Each transfer valve comprises a valve member which is engageable with a seating. The yieldable spacers by which the valve members may be held away from the seatings may be the thickness of a film of hydraulic fluid therebetween.

Abstract: An arrangement for controlling the supply of pressurized hydraulic fluid from a master cylinder and from a pressure source into hydraulic circuits leading to wheel brake actuating cylinders includes a valve device including a control piston acted upon by a spring-loaded auxiliary piston in one direction and by the pressure in a return conduit in the opposite direction. Upon brake pedal depression, hydraulic fluid pressure from the pressure source acts on the auxiliary piston in opposition to the spring force so that the auxiliary piston ceases to act on the control piston. Then, as hydraulic fluid is discharged from the brake actuating cylinders during antiskid control action, pressure builds up in the return conduit and propagates to the control piston to move the same into its open position in which it admits pressurized fluid from the pressure source to check valves which are acted upon in opposition to their opening by the tandem master cylinder pressures.

Abstract: An apparatus for controlling braking liquid pressure produces a proportionate reduction in an input liquid pressure supplied from a master cylinder before it is output to a rear wheel cylinder. The apparatus includes a body which is formed of a single member and which is formed with a bore in which a plunger slides. An annular retainer having an inner diameter less than that of the bore is fitted into the bore at its end nearer the master cylinder. One end of the plunger extends through the annular retainer.

Abstract: A tandem brake master cylinder comprising a longitudinal bore having two pressure chambers therein each associated with a different one of two pressure pistons, each of the two pressure chambers and its associated one of the two pressure pistons are associated with a different one of two brake circuits. Two parallel inlet sockets are provided in the housing of the tandem master cylinder, each of the two inlet sockets connecting a different one of the two pressure chambers to a brake fluid reservoir. A transverse bore is also provided in the housing of the tandem master cylinder containing a pressure control device for one of the two brake circuits, the control device including a stepped piston and a valve controlled by the stepped piston. The transverse bore intersects a plane containing the axes of the two inlet sockets in an approximate perpendicular manner between the two inlet sockets and beween the longitudinal bore and the reservoir.

Abstract: A hydro-pneumatic actuator for providing a two-stage buildup of the hydraulic output pressure. A primary hydraulic piston, to which a pneumatic input piston actuator is connected, acts in a larger bore of a hydraulic cylinder to transfer fluid via a central passage in a spring-loaded, differential area, secondary hydraulic piston, that is coaxially disposed in the hydraulic cylinder in spaced-apart relationship with, and downstream of, the primary piston. A larger face of the secondary piston is in the larger bore and the smaller face is in a reduced diameter bore of the hydraulic cylinder, so that a pressure buildup in the hydraulic cylinder effects actuation of the secondary piston to close a check valve and thereby inter-fluid communication between the larger and smaller bores of the hydraulic cylinder via the central passage.

Abstract: The control valve comprises a member defining an orifice for fluid and a resilient plate arranged to control flow of fluid through the orifice by flexing movement relative to the orifice. The plate may comprise a disc which is freely movable between first and second stops. The plate is arranged to engage the first stop to control fluid flow in one direction through the orifice by said flexing movement and is arranged to engage the second stop to permit relatively greater flow when fluid flows in the opposite direction through the orifice.

Abstract: A concrete pump comprises a pair of separate pump assemblies each having a cylinder, a piston subdividing same into a piston-side front compartment and a rod-side rear compartment, and a piston rod connected to the respective piston and extending out of the respective cylinder through the respective rod-side rear compartment. The pump also has a liquid supply having a high-pressure side and a low-pressure side for supplying liquid under high pressure at the high-pressure side and for taking in liquid at the low-pressure side.

Abstract: A master cylinder includes a housing (22) with a bore (24) for receiving a pair of pistons (36, 38). The housing defines a reservoir (28) with an outer wall (26). The housing also defines at least one outlet passage (62, 66) communicating fluid from the bore (24) to a brake assembly (16). The outlet passage (62, 66) is partially defined by a boss (60) formed integrally with the housing (22) and the boss (60) cooperates substantially with the outer wall (26) to separate the reservoir (28) into a pair of cavities (84, 86).

Abstract: There is disclosed an air operated demand only hydraulic power unit for supplying hydraulic fluid under presure to one or more hydraulic working motors, comprising an extensible pneumatic power motor including an extensible power transmitting member, an extensible hydraulic slave motor including an extensible slave member powered by said power transmitting member, said slave motor being connected to each said hydraulic working motor to power same, valving for controlling the supply of air and oil to said power and slave motors, and a reset valve for insuring full volume cycling of said slave member in said slave motor. In one embodiment the reset is indicated by sensing the various pressure changes after all working motors are extended and then valving leftover oil to a reservoir. A second embodiment accomplishes the reset on a time delay basis.

Abstract: A method and apparatus for simultaneously adjusting the fluid pressures in a dual hydraulic circuit arrangement in which in a first hydraulic circuit pressurized fluid is supplied from a first pressure source to a first fluid pressure activated device and in a second hydraulic circuit pressurized fluid is supplied from a second pressure source to a second pressure activated device, comprising a cylinder having opposite closed ends and spaced bulkheads therein defining a central chamber between the bulkheads and a pair of chambers on respective opposite sides of the bulkheads. A pair of spaced first pistons are slidably mounted in the central chamber to define a control pressure chamber therebetween and first and second primary fluid pressure chambers between respective pistons and the bulkheads. The first primary fluid pressure chamber is connected to the first pressure source while the second primary fluid chamber is connected to the second pressure source.

Abstract: In a pneumatic-hydraulic system for driving a hydraulic actuator, a single pneumatic-hydraulic converter includes a cylinder casing with inlet and outlet ports and a plunger reciprocably disposed within the casing to form a hydraulic chamber in open communication with the inlet and outlet ports and a pneumatic chamber for connection to a pneumatic pressure source, the hydraulic chamber having a displacement capacity filled with a predetermined amount of hydraulic fluid necessary for producing at least one reciprocating motion of the actuator.

Abstract: A tandem master cylinder has a primary and secondary pistons disposed within cylinder bore formed in a cylinder housing, in tandem relationship. The secondary cylinder is formed with a longitudinally extending bore in which is disposed a pressure regulating valve. The pressure regulating valve has a variable set pressure which defines a split point with respect to the pressure applied to the front and rear wheel cylinders. The pressure regulating valve includes a member for varying the set pressure in response to damage to the hydraulic circuit of the front wheel cylinders for setting the split point higher than in the normal state.

Abstract: The present invention relates to a simple valve device capable of reducing hydraulic pressure to the front wheel brake cylinders of a vehicle to reduce the tendency of front wheel skidding.

Abstract: A brake unit comprising a hydraulic booster unit connected to hydraulic auxiliary energy and controllable by a brake pedal via a control piston drives a master brake cylinder unit to supply brake pressure to wheel brake cylinders through at least one hydraulic line connected to an output of the master brake cylinder unit. A bypass line connected to the work chamber of the booster unit supplies a preliminary feed of the auxiliary energy to the wheel brake cylinders to overcome the brake clearance. A two way, two position changeover valve is connected to the hydraulic line, the bypass line and the wheel brake cylinders to connect during a braking operation either the bypass line or the hydraulic line to the wheel brake cylinders dependent on the pressure in the two lines. This brake unit requires only a few hydraulic connections external of the unit, has a single construction, has small dimensions, has exact operation and has quick response.

Abstract: A brake valve useable in conjunction with a vehicle braking system monitored by an anti-locking device and operable by a brake pedal through a trailing spring sometimes also called a simulating spring. The brake valve is provided with a control slide valve longitudinally displaceable by the trailing spring. The slide valve regulates a metered feed of the pressure medium conducted from a pressure source to the wheel brake cylinders. The pressure medium is relieveable at the wheel brake cylinders by anti-lock valves. The slide valve includes two control slide valves of which is associated with a pressure reservoir. One control slide valve cooperates with an emergency piston providing free through-flow during normal operation of the braking system. The emergency piston, upon a failure of the pressure medium source, after an emptying of the pressure reservoirs, is operable mechanically by the brake pedal after a spring-loaded ball valve has been closed at the emergency piston.

Abstract: A master cylinder includes a housing defining a reservoir containing fluid. A bore within the housing communicates with the reservoir and movably receives a pair of pistons which substantially define a pair of pressure chambers. One of the pistons includes a cavity movably receiving a position sensitive piston which cooperates with the one piston to define an auxiliary pressure chamber. When the one piston is moved during a brake application, the position sensitive piston is movable relative to the one piston to generate fluid pressure within the auxiliary pressure chamber. A passage between the auxiliary pressure chamber and one of the pair of pressure chambers provides one way communication between the auxiliary and one pressure chambers.

Abstract: Dual circuit pressure control valves for brake system are known in which the control pistons are located parallel to each other with each control piston controlling a different one of two brake circuits. Both control pistons are loaded by a common preloading force. The known arrangement is complicated in its construction and has a large overall length. According to the present invention, the construction is simplified and the overall length is reduced by providing a torsion spring which provides the preloading force acting on the control pistons via stationarily supported swivelling levers.

Abstract: A liquid cable transfer device is provided for transmitting input forces and/or displacements to corresponding output forces and/or displacements. The transfer device includes a section of tubing adapted to accommodate liquid under pressure, and terminal units attached to opposite ends of the tubing. Each unit includes a piston and a biasing element acting against the piston whereby the pistons of both units coact to maintain a certain minimum liquid pressure within the tubing. The piston displacement stroke within one terminal unit caused by either a pull or push input force being applied thereto is transmitted to the piston within the second terminal unit whereby the latter piston is displaced from its initial equilibrium position a predetermined amount.

Abstract: A master cylinder having a fluid pressure control valve mechanism which is constituted by a cylinder body, pistons slidably received in the cylinder body for defining pressure chambers in cooperation with each other and with one end wall of the cylinder body, respectively, a fluid pressure supply chamber in communication with a reservoir and isolated from the pressure chambers, a fluid pressure passage extending between one of the pressure chambers and a brake cylinder and a fluid pressure control valve mechanism having an annular space in communication with the fluid pressure supply chamber and isolated from the one pressure chamber.