Abstract: A casing (10) has an inlet (20) and a valve chamber (40) connected to the same as well as an outlet (60). In the valve chamber (40) a valve seat (54) is arranged at the entrance of a passage (52) leading to the outlet (60) and furthermore a valve member (42) is arranged for brake fluid to flow around it. The valve member is movable in response to deceleration from an inoperative position against the valve seat (54). A barrier member (26) is arranged between the inlet (20) and the valve member (42) for flow of brake fluid around or through the same. The barrier member is movable from an inoperative position remote from the valve member (42) until it hits the valve member (42), at least approximately in the direction of movement thereof.

Abstract: A fluid pressure controlling valve for a dual-path brake system having a small of number of parts, compact construction, low cost and high reliability. The valve includes a pressure reducing valve for outputting an input fluid pressure of the first system and a follower valve for outputting a fluid pressure of the second system substantially equal to that of the first system and following the output fluid pressure of the first system. The follower valve is connected in series with the pressure reducing valve and has a first pressure receiving portion receiving an output fluid pressure of the first system in a valve opening direction and a second pressure receiving portion receiving an output fluid pressure of the second system acting in a valve closing direction and having an area equal to that of the first pressure receiving portion.

Abstract: Two separate hydraulic master cylinders are connected with pressure lines to the front and rear brake cylinders. These two master cylinders are mechanically connected together by an articulating balance bar, all of which is mounted on a slidable mounting bracket. The mounting bracket is slidably movable by a reversible electric motor driving a worm gear that is connected to the mounting bracket. The relative position of the mounting bracket on its mounting plate in relation to the input point of a push rod determines the proportioning ratio of the two master cylinders. The assembly may be moved to obtain any proportioning ratio from 100% front brake to 100% rear braking.

Abstract: A pressure control device to be inserted into a connection between a front wheel brake and a rear wheel brake which determines the rear brake hydraulic pressure in dependence upon front brake hydraulic pressure. The pressure control device provides a plurality of valve pistons hydraulically connected in parallel and displaceable by front axle hydraulic pressure in opposition to a control force. A predetermined change-over hydraulic pressure develops a braking pressure in the rear brake which is less than the front brake pressure. The valve pistons are provided by stepped pistons guided within stepped bores, each of which pistons provides smaller and larger effective pressure surfaces.

Abstract: A deceleration-sensitive braking pressure control unit having a ball valve freely movable in an inlet chamber of the housing of the unit. The ball opens or closes a channel for the passage of pressure fluid through a longitudinally slidable, pressurized stepped piston upon attainment of the change-over pressure with the vehicle loaded. The stepped piston is movable in the longitudinal bore of a pressurized annular piston which is supported slidably in the housing. In this arrangement, the annular piston is slidable in the housing to control the pressure fluid passage between its annular end face and the surface of the ball upon attainment of the change-over pressure, with the vehicle unloaded. Both the stepped piston, which contains the channel and the annular piston are comprised of varying effective surfaces acted upon by pressure fluid and are maintained in their initial positions in the housing by springs.

Abstract: A brake pressure regulator for an hydraulic vehicle braking system. A first inlet chamber (14) and an outlet chamber (20) for a first brake circuit (HzI-RzI) are defined by piston surfaces of different sizes of a stepped piston (30) which controls a valve (40) disposed in a connection between these two chambers (14, 20). The pressure in a second inlet chamber (24) adapted to be connected to a second brake circuit (HzII-RzII) acts on an annular control piston (50) which is acted upon in opposite direction by a spring (60). The control piston (50) surrounds the stepped piston (30) without contacting the same and is sealed radially inwardly against a plug (16) which is inserted in the housing (10) and which in turn surrounds the stepped piston (30) in sealing fashion. When as switching pressure in both brake circuits (HzI-RzI, HzII-RzII) is surpassed, the stepped piston (30), aided by the control piston (50), adopts a position at which the valve (40) closes.

Abstract: In a brake pressure control valve having two valve units arranged therein, there is disposed a free piston self-centering promoting arrangement. The arrangement comprises a shoulder portion of a hollow member which is retained in each valve unit to retain the substantially all essential parts in a casing, a radially outwardly projected portion of the free piston which is axially slidably received in the hollow plug with its outside end contacting with the pair, and an annular spring seat which supports one end of a biasing spring of the pressure control piston of the unit, wherein the spring seat is in abutment with both the shoulder portion and the radially outwardly projected portion at the same time when the free piston assumes its home position.

Abstract: The brake comprises a torque control valve comprising a main piston which cooperates via a bearing piece with a shoe of which the bearing force is representative of the torque supplied by the brake during operation of the brake motor. The main piston controls the pressure admitted to the brake motor by a cut-off valve responsive to displacement of the main piston and by a variable volume decompression chamber of which a movable wall decompresses the fluid contained in the brake motor when the torque generated by the brake exceeds the limit of a predetermined torque-pressure law.

Abstract: In a brake oil pressure controlling valve device for vehicles of the type wherein a reducing valve adapted to proportionally reduce output oil pressure from a master cylinder to transmit it to a rear wheel brake and a pressure adjusting spring for urging the reducing valve in the valve opening direction and determining the reduction starting pressure thereof, are interposed in an oil path connecting between an output port of the master cylinder and the rear wheel brake, the disclosed valve device is further provided with: a pressure reducing piston which is normally held by virtue of resilient force of a set spring at its advanced limit position where the reducing valve is made open and which is retreated to close the reducing valve and to reduce oil pressure on the output side of the reducing valve when the resilient force of the set spring is released; a controlling oil pressure chamber supplied with oil pressure from an oil pressure source when a rear wheel is about to come into a locked state; and a contr

Abstract: An interlock braking system for motorcycles comprising a brake pedal, a single master cylinder which generates a braking pressure according to an external force applied to the brake pedal, first and second brake mechanisms connected to the master cylinder for applying first and second braking forces according to the braking pressure to the front and rear wheels, respectively, and an anti-lock mechanism for changing the braking pressure according to rotational speeds of the front and rear wheels to prevent the wheels from becoming locked. In this manner, the interlock braking system effectively avoids the occurrence of a wheel-lock condition when braking the front and rear wheels of a motorcycle.

Abstract: Dual-circuit pressure control valves are known in which the two control pistons are acted upon by a common preloading force through the intermediary of a preload distributor. The disadvantage of the known devices is that the valve closure travel is great resulting in a large fluid volume input to the control valve. According to the present invention this disadvantage is overcome by providing adjustable stops which cooperate with corresponding extensions of the distributor as soon as an unsymmetrical mode of operation of the valves occurs.

Abstract: A brake pressure control valve for a diagonal brake circuit having two pressure regulating valves is proposed. If one of two brake lines fails, the pressure regulating valves are adapted to be made inoperative so that the brake pressure will not be reduced. The valve head on the plunger passes through a lip seal of an elastic material.

Abstract: A hydraulic pressure control valve for an automobile brake mechanism which is provided with a first hydraulic pressure passage communicating with each brake units of, for instance, front wheels, and a second hydraulic pressure passage communicating with each brake units of, for example, rear wheels, and in which a plunger 5 is disposed in at least one or both of the hydraulic pressure passages and at least one hydraulic pressure regulating mechanism for converting the hydraulic pressure of a brake liquid as desire for instance, a poppet valve 14, is provided in association with the plunger in the hydraulic pressure passage having disposed therein the plunger, and in which blocking member is provided for inhibiting the plunger 5 from moving in a direction in which to cut off the brake liquid when the hydraulic pressure of either one of the hydraulic pressure passages fails.

Abstract: A hydraulic pressure control valve for use in a dual circuit braking system of an automotive vehicle, and including a plunger slidably received in an elongated bore in a housing with opposite ends thereof being exposed to respective pressure circuits, and two pressure proportioning valve mechanisms being mounted on the housing with the axii thereof being perpendicular to the plunger, each valve mechanism including a stepped piston, an axial passage extending through the piston, a valve seat defined on one end of the passage, and a valve member cooperating with the valve seat.

Abstract: A hydraulic brake system for a vehicle includes first and second brake lines communicating with first and second rear wheel brakes, respectively, for supplying hydraulic fluid under pressure thereto and first and second valves arranged in the first and second brake lines, respectively. Each valve has a deceleration and acceleration responsive movable valve member controlling, as a function of its position, the flow of hydraulic liquid through the brake line with which the movable valve member is associated and a guide track guiding the associated movable valve member with a single degree of freedom of motion. Each guide track slopes downwardly towards the vehicle rear at an angle .alpha. with respect to a horizontal plane and further, each guide track inclines away from the longitudinal vehicle axis outwardly towards the vehicle rear in the direction of the associated rear wheel brake at an angle .beta. which a vertical projection of each guide track onto a horizontal plane defines with the vehicle axis.

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: An improved fluid pressure controlling device for a vehicle braking system has a valve housing provided with an input chamber communicating with an output port of a master cylinder and an output chamber communicating with a rear wheel brake. A resilient valve seat separating the input and output chambers from each other is disposed in the input chamber. The resilient valve seat is provided with a valve port through which the input and output chambers are communicate with each other. A valve member is accommodated in the output chamber for opening and closing the valve port. The valve member is resiliently biased by a spring in a direction to move the pressure-receiving piston away from the resilient valve seat. The valve seat has an inner peripheral portion with a conical valve seat surface opposing the valve member and an annular thin-walled portion surrounding the inner peripheral portion.

Abstract: A deceleration sensing valve is provided which includes a valve body adapted to move under its own inertia as the deceleration of a road vehicle exceeds a given value, and a valve seat on which the valve body seats. The valve seat is located rearwardly of the valve body as viewed in the direction of movement thereof under its inertia, whereby there can occur no change in a control pressure derived by the deceleration sensing valve, in particular when the vehicle is empty, as it does occur in the prior art in response to any slight shift in the timing when the valve body becomes seated. Consequently, when used in combination with a proportion valve, the deceleration sensing valve of the invention assures a stable braking characteristic when the vehicle is empty as well as when the vehicle is occupied.

Abstract: An improved hydraulic braking pressure control device for a dual braking system including a pair of first and second hydraulic lines extending from a dual type brake master cylinder to the front and rear wheel brakes. The device includes a common housing mounted across the first and second hydraulic lines, and a pair of differential pistons slidably received in the aligned cylinder bores in the housing to respectively define on their opposite sides a first input and a first output hydraulic chamber and a second input and a second output hydraulic chamber, the adjacent input and output chambers being in communication with each other through respective valves which are operated to open and close by a pair of valve actuating pistons slidably fitted in the respective input chambers. A pressure control spring is arranged between the differential pistons to urge them in the direction away from each other.

Abstract: An hydraulic brake actuator comprises opposed pistons which work in bore portions in a housing and fluid pressure in a pressure chamber urges the pistons in opposite directions to separate adjacent ends of a pair of brake shoes. A pressure proportioning valve controls communication between pressure spaces constituted by the pressure chamber. The valve is normally open to equalize the pressure in the pressure spaces but closes at a predetermined pressure so that any further increase in pressure is operative in only one pressure space, the pressure in which space acting to keep the valve closed. In use in a brake of the one-leading one-trailing shoe-drum type the increased pressure acts on the piston which applies the trailing shoe to the drum, in order to equalize the torque.

Abstract: The invention relates to an improvement in a valve for a tractor air brake system for changing the pressure delivered to air brakes on a tractor rear axle during "bob tail" operation and particularly to a valve wherein the ratio is changed by communication of control pressure to a second control surface in accordance with the presence of trailer emergency pressure. The improved ratio control valve enables fluid pressure communication to both control surfaces of the ratio valve until a predetermined input pressure is reached so that the "crack-open" input pressure for both the "trailer-connected" and the "bob tail" modes of operation will be the same. Further in accordance with the invention, a blend-back valve is provided which is biased by the available fluid pressure in the tractor reservoir tank so that the maximum available tractor reservoir pressure may always be applied to the tractor rear axle brakes even when the trailer is operating in the "bob tail" mode.

Abstract: A free piston is reciprocally disposed within a first plunger unit associated with one of two circuits which plunger also houses a poppet valve actuatable by the free piston. A second plunger is reciprocally received in one end of the first plunger unit and also has a poppet valve actuatable by the free piston. The second plunger is biased toward the first by an actuator piston/spring arrangement subject to control by a valve responsive to vehicular deceleration. During pressure modulation the free piston reciprocates back and forth rapidly, opening and closing each of the poppet valves. Upon failure of one of the dual circuits both of the plungers shift in the same direction causing one poppet valve to remain open and prevent pressure modulation. Upon failure of the other circuit, the pressure transmitted by the arrangement markedly increases to produce the necessary deceleration to close a deceleration sensitive valve and induce modulation.

Abstract: An hydraulic actuator comprises a first piston and a second piston both working in a bore in a housing and the actuator incorporates a pressure proportioning valve. The valve comprises a valve head for engagement with a seating, first and second stems projecting from the head and through the first piston in each of two opposite directions, each stem being of an area smaller than that of the head, a seal between the first stem and the first piston, a first spring acting between an abutment adjacent to the seal and a shoulder on the first stem to urge the head in a first direction away from the seating and into engagement with a stop, and a second spring acting on an enlargement on the second stem also to urge the head in the first direction and to augment the force in the first spring. The second piston is provided with a longitudinally extending recess into which the second stem and the second spring both project.

Abstract: A hydraulic braking system is provided for vehicles which frequently experience variable loading conditions ranging from maximum to near minimum gross vehicle weights. The system comprises dual proportioning valves, hydraulically in series with one another, one valve includes a unique spring driven digital cam which, in response to compression of the vehicle suspension system, selects the desired master cylinder to brake pressure relationship for the vehicle load condition.

Abstract: Valve assemblies for single and dual circuit braking systems are described. An assembly for a single circuit (FIG. 1) has a primary piston provided with a normally open valve seat engageable by a deceleration sensing ball housed in the primary piston. An annular secondary piston is slidably mounted on the larger diameter end of the primary piston. Primary piston has an area (A.sub.2) exposed to outlet pressure in a chamber and a smaller area (A.sub.1) exposed to inlet pressure in a housing bore portion, and is capable of rearward movement against biassing of a spring. Rearward movement of secondary piston is restricted firstly by a flange on the primary piston and secondly by a step on the housing.

Abstract: A hydraulic pressure control valve for use in a vehicle hydraulic braking system having first and second pressure circuits include a common valve housing, first and second pressure control mechanisms including respectively stepped pistons, valve mechanisms and inlet and outlet chambers, a spring force controlling pressure chamber normally connected to the inlet chamber of the first pressure control mechanism and transmitting the force of a spring to the pistons of the both mechanisms, and an inertia valve arranged in a passage connecting the inlet chamber of the first mechanism and the spring force controlling pressure chamber. The inertia valve closes when the deceleration of the braked vehicle exceeds a predetermined level as determined by the loading condition of the vehicle and the pressure in the inlet and outlet chambers in the respective pressure control mechanisms.

Abstract: A brake system for motor cycles is disclosed which includes a hydraulic master cylinder supplying a front brake and a rear brake and a pressure-regulating valve having a calibrating spring adapted to limit the maximum pressure on the rear brake to a predetermined value. The compression of the calibrating spring of the pressure-regulating valve is controlled by the relative motion of two distinct points on the rear shock spring.

Abstract: A deceleration detecting valve for use in a vehicle hydraulic braking system having a master cylinder, a first circuit connecting the master cylinder with front wheel brakes and a second circuit connecting the master cylinder with rear wheel brakes. The valve has a chamber, and a gravity ball received in the chamber and movable from a first position to a second position in receiving a predetermined deceleration thereby restricting the pressure acting on rear wheel brakes. A slidable member is provided in the chamber with one end thereof receiving the pressure in the first circuit, and ball guiding surfaces are defined on the wall of the chamber and on the slidable member. When the first circuit fails the slidable member retracts in the chamber, and a gap is formed between the ball guiding surface on the slidable member and that of the wall of the chamber thereby impeding the movement of the ball.

Abstract: A hydraulic pressure control valve for a dual-circuit brake system of a vehicle. In this control valve a pair of valve pistons for controlling the braking hydraulic pressure delivered to each of rear wheel brakes are disposed in a housing parallelly and imparted with biasing force directed inwards of the housing by one biasing device. The biasing device is assembled or set within a cover of cup-shape such that the biasing device has been given a preload substantially equal to a biasing force necessary for the control valve before the cover is fixed to the valve housing. The biasing device includes a swingable guide rod attached at one end thereof to the cover with a pivot pin, a sliding member slidably fitted on the guide rod, and a compression spring disposed between the sliding member and a free end of the guide rod for biasing the sliding member toward the pivoted end of the guide rod.

Abstract: In a pressure control valve for a hydraulic brake system for vehicles, the closure member is carried by a control piston which has one of its ends guided through an annular seal and in a housing bore, which is preferably connected to atmosphere, and carries adjacent its other end a support plate for engagement with a valve spring. The valve seat is part of an annular body encircling the control piston and held in place by a tubular body surrounding the annular body and the control piston and secured to the housing. A return channel is formed between the annular body and the tubular body and incorporates therein a check valve opening in the direction from the outlet chamber to the inlet chamber. The annular seal is in abutment with a step in the housing and the annular body is in abutment with an inner flange of the tubular body. To obtain a minimum possible overall axial length, the annular body and the annular seal are arranged adjacent each other, leaving a clearance for radial channels.

Abstract: A brake pressure regulating valve inserted inside the pressure chamber of a wheel brake cylinder of a vehicle comprises a differential or stepped piston having its smaller diameter section slidably supported in a bore of a wheel brake cylinder piston and its larger diameter section guided in the bore of a housing for the wheel brake cylinder. The larger diameter section of the stepped piston has an internal bore between an inlet chamber and an outlet chamber. A regulating valve controlling the inlet of the internal bore is provided by a sealing ring resting against a surface of the larger diameter section of the stepped piston adjacent the inlet chamber and an adjacent end of the wheel brake cylinder piston.

Abstract: In a fluid pressure control valve unit, a pair of first and second partition members are assembled within a housing to subdivide the interior of the housing into first and second chambers and to provide a space between the partition members. The first chamber is in open communication with an outlet port for connection to rear wheel brake cylinders, and the second chamber is in open communication with an inlet port for connection to a master cylinder. Assembled within the first chamber are a stepped piston and a control valve assembly cooperable with the piston. The piston extends through the first partition member into the space, and a control plunger is slidably disposed within an axial bore of the second partition member to provide a third chamber opening toward the second chamber. An inertia-control valve assembly is disposed within the second chamber to control the pressure in the third chamber in accordance with the rate of deceleration.

Abstract: A fluid pressure proportioning valve (48), particularly of the type which is used in the hydraulic braking systems of automotive vehicles, includes a plug member (28) movably carrying a piston member (50). The piston member (50) defines a through bore (88) communicating pressurized fluid to an outlet on the plug member (28). The piston member also carries a valve member (116) opening and closing the through bore (88) in response to reciprocation of the piston member (50). A lip seal (62), spring seat (100), and a coil spring (110) are carried by the piston member (50). The plug member (28), piston member (50), valve member (116), lip seal (62), spring seat 100, and coil spring 110, comprise a unitary subassembly (142) which may be assembled with a housing providing a bore for receiving the coil spring (110) and lip seal (62) and providing an inlet communicating pressurized fluid from a master cylinder (10).

Abstract: There are known dual-circuit pressure control valves including a pressure control valve having a stepped piston for each of the dual brake circuits with each of the stepped pistons being subjected to a common control force by a circular compensation member. This known device is, however, insecure in its operation and expensive to manufacture due to the material used and the construction of the parts. These disadvantages are overcome in accordance with the present invention by providing a compensation member in the form of a solid of revolution whose radius of curvature is considerably smaller than the radius of curvature of the supporting surface. The control pistons are disposed in a V-shaped with respect to the compensation member.

Abstract: A hydraulic pressure control valve for controlling braking pressure of two independent circuits and including two stepped pistons with the large ends being exposed respective outlet pressure and the small ends thereof being exposed to a control chamber which is connected through an inertia valve mechanism to the inlet of one circuit. The stepped pistons receive the pressure in the inlets of respective circuits at the intermediate portions thereof and incorporate therein valve mechanisms connecting normally the inlets and outlets. There are further provided a spring biased plunger retractable in receiving the pressure in the control chamber, and a stepped emergency piston with the large end being exposed to the control chamber and normally separated from the small end of the stepped piston of the other circuit. The small end of the emergency piston is exposed to the pressure of the inlet of the other circuit.

Abstract: A valve for a tractor air brake system for changing the pressure delivered to air brakes on the rear axle depending on whether the trailor is attached or whether the tractor is operating in the "bob tail" mode. According to the invention, a rear axle ratio control valve provides an automatic selection of input to output ratio in accordance with the presence or absence of trailor emergency pressure. In the ratio control valve, service brake control pressure always acts against a first effective area of a piston for providing a first ratio of input to output. A second effective area of the piston receives pressure with the presence of the trailer emergency so that the ratio of pressure delivered from the valve will be changed. Further in accordance with the invention, a blend-back valve operates at a higher, predetermined pressure range, even when the pressure communication is closed by the absence of the emergency pressure to enable the valve to deliver the maximum pressure at high input pressure.

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 braking fluid pressure control apparatus for a dual circuit type vehicle brake system. The control apparatus is provided with a pair of pressure reducing or pressure limiting valve plungers disposed in a housing parallelly one another, with respective rear ends being protruded out of the housing, and a biasing device for commonly biasing both rear ends into the housing. The biasing device includes a guide rod pivoted to the housing at an intermediate position of the pair of valve plungers oscillatably in a parallel direction to a plane including the axes of both plungers. On the guide rod a transmitting member having an operating portion abuttable to the rear ends of both plungers is slidably fitted and biased by a spring toward the rear ends of the plungers.

Abstract: A deceleration sensing valve is provided which includes a valve body adapted to move under its own inertia as the deceleration of a road vehicle exceeds a given value, and a valve seat on which the valve body seats. The valve seat is located rearwardly of the valve body as viewed in the direction of movement thereof under its inertia, whereby there can occur no change in a control pressure derived by the deceleration sensing valve, in particular when the vehicle is empty, as it does occur in the prior art in response to any slight shift in the timing when the valve body becomes seated. Consequently, when used in combination with a proportion valve, the deceleration sensing valve of the invention assures a stable braking characteristic when the vehicle is empty as well as when the vehicle is occupied.

Abstract: In a known dual-circuit braking pressure control valve, a tilting lever arrangement is provided for distribution of the preloading force to the two control pistons, whereby the change-over point of the intact brake circuit is increased upon failure of one brake circuit. The tilting lever arrangement is complicated with respect to its construction and assembly, and its mode of operation is not safe. According to the present invention the tilting lever arrangement is replaced by a carrier bridge at the ends of the two pistons which synchronizes the points of application of the preloading forces by allowing a slight relative movement betweeen the two pistons when both of the brake circuits are operative.

Abstract: In general pressure regulators for motor vehicle brake systems are arranged in the pressure medium line between the master brake cylinder and at least one wheel brake cylinder. The pressure regulator comprises a plunger valve with different pressure surfaces, which above a certain pressure level, reduce the brake pressure of the rear axle compared to the brake pressure of the front axle. In order to achieve a high reliableness and a simple construction of the pressure regulator, a non-return valve in the form of a sealing lip movable by a movable part of the plunger valve is provided. The sealing lip extends into the inlet chamber when the plunger valve is closed and closes a channel which leads through the valve plunger and/or valve body to the outlet chamber.

Abstract: In an anti-skid braking system, a first proportioning valve has a plunger which is axially movable in a direction against a spring in response to the application of hydraulic pressure to a first fluid inlet port to control the magnitude of hydraulic pressure at a first fluid outlet port. A second proportioning valve functions to open and close a passage between a second fluid inlet port and a second fluid outlet port. A free-piston is axially movably disposed between the first and second proportioning valves to provide these valves with synchronous opening and closing operations, thereby allowing the second proportioning valve to control the magnitude of a hydraulic pressure at the second outlet port in response to the application of a hydraulic pressure to the second fluid inlet port.

Abstract: A deceleration-sensitive brake pressure control device is disclosed which has a pressure proportioning valve, an inertia body, a sealing chamber, a piston and two springs. The piston is adapted to move without affecting the operation of the proportioning valve until its stroke reaches a predetermined value. An orifice is provided upstream of the sealing chamber to cause some delay in the increase in the pressure in the sealing chamber.

Abstract: The correcting valve comprises two identical parallel pistons which control the opening or closing of two valves which are disposed between two inputs and two outputs of two braking circuits. Two thrust members which are subjected to a control pressure urge the pistons in the direction for opening the valves. Two reaction springs co-operate with two transmission members for urging the thrust members in the opposite direction. When the two brakes circuits are supplied, the correcting valve has an identical cut-off pressure for the two circuits. In the event of failure of one of the circuits, the transmission members come into mutual engagement, resulting in a doubling in the cut-off pressure in the circuit which is still intact. The invention is used for dual-circuit braking systems for motor vehicles.

Abstract: In a dual-circuit pressure control valve for hydraulic brake systems, the control pistons disposed parallel to one another are each loaded by a first arm of an associated angular lever. Each of the levers have a second arm perpendicular to the first arm acted upon by a common tension spring disposed therebetween. The levers are located approximately in a plane defined by the axes of the control pistons. The tilting axes of the levers are disposed perpendicular to this plane and are disposed outside the axes of the control pistons. This results in a short overall length in both the axial and radial direction. In addition, a carrier device is provided which couples one of the control pistons with the lever of the other control piston after a small relative movement of the control pistons. This carrier device becomes effective upon failure of one brake circuit. The carrier device may be formed by extensions of the first arms which overlap one another with play.

Abstract: In known brake pressure control units having two pressure control valves arranged in parallel, a tipping lever arrangement is provided for the distribution of the preload force provided by a spring to the control valves which in the event of a failure of one brake circuit will increase the change-over point of the intack brake circuit. This tipping lever arrangement is complicated. Therefore, a brake pressure control unit having two pressure control valves arranged in parallel is disclosed in which the arrangement for the distribution of the preload force comprises a piston tiltable within limits which piston is subjected to the spring force and is directly operatively connected with ends of the two control pistons.

Abstract: An improved hydraulic pressure control valve device includes a valve housing having first and second inlet ports of the master cylinder, respectively, first and second inlet ports communicated with the left and right rear wheel brakes of the vehicle, respectively, a first control pressure chamber interconnecting the first inlet port and the first outlet port, a second control pressure chamber interconnecting the second inlet port and the second outlet port, and a cylinder bore interconnecting the first and the second outlet ports; a pressure reducing valve adapted to normally open the first control pressure chamber and to open and close the first control pressure chamber as the pressure at the first inlet port exceeds a predetermined level so as to transmit the pressure to the first outlet port while proportionally reducing the pressure; a cut-off valve adapted to normally open the second control pressure chamber in the normal state, a valve rod integrally connected to the reducing valve to operate the cut-of

Abstract: A double piping type hydraulic pressure control device in which hydraulic pressure control of a hydraulic pressure channel A is transmitted to another channel B in such a manner that the hydraulic pressure to be exerted on a balance piston for hydraulic pressure control is obtained solely from the hydraulic pressures of the two output chambers while two input hydraulic pressures are arranged to have nothing to do with the control action.

Abstract: An improved brake pressure control device is disclosed which has an inertia valve, a sealing chamber, a piston and a pressure proportioning valve. Between the piston and the valve plunger are arranged two springs carried by a U-shaped plate so that the piston will not act on the valve plunger until the pressure in the sealing chamber reaches a predetermined level.

Abstract: A brake pressure control device of deceleration responsive type includes an inertia-controlled valve element cooperating with a valve seat in a valve chamber to control the ratio of brake fluid pressures being applied to front and rear wheel brake cylinders in response to the attainment of a predetermined rate of deceleration of the vehicle. In the control device, a partition member is assembled within the valve chamber to ensure the precise initial setting of the valve element, the partition member being further provided with a fluid passage to ensure the optimum control of fluid flow acting on the valve element.