Abstract: The modulator is intended, under the control of a solenoid valve, for diverting a flow of fluid under high pressure from the fluid supply circuit of a hydraulic motor.The solenoid valve is a progressively acting solenoid valve, the shutter (70) of which is capable of more or less closing communication between the fluid inlet (56) and the inlet chamber (108) of the regulator as a function of the signal applied to the solenoid valve; furthermore, the spring (116) bears on a piston (132) which closes the regulating chamber (117) and behind which is formed a reaction chamber (128) communicating with the fluid inlet (56).

Abstract: The invention relates to the braking of a motor vehicle. During periods when the anti-lock device is in operation, pressure pulses occur in the brake circuit. To prevent these pressure pulses from being transmitted to the master cylinder, a non-return valve (11) is arranged in the circuit so as to prevent any return of the brake fluid into the master cylinder during periods of anti-lock braking. The non-return valve (11) is closed as a result of the pressure of the fluid from the accumulator (24), itself fed by the pump (23) which is started up by the computer of the anti-lock device at the same time as the expansion of the brake fluid is controlled by the solenoid valve (16). At the end of the braking period when the petal (3) is released, the fluid in the brake circuit can return into the master cylinder via the line (28) and the non-return valve (12). The invention is used for eliminating pulses in the brake pedal during the periods when the anti-lock device is in operation.

Abstract: The invention relates to the control of a hydraulic jack which can be used, for example, for controlling the orientation of the rear wheels of a vehicle with front guiding wheels. In the event of a failure in the supply of fluid under pressure to the chambers (3, 4) of the jack, these chambers are isolated and the piston (2) is maintained in the position which it occupied when the failure occurred, by means of non-return valves (12). However, when certain conditions are satisfied, for example a sufficiently low speed, the electronic control member (20) activates an auxiliary circuit (30 to 39) in order to return the piston to its middle position and allow driving of the conventional kind with the rear wheels in line.

Abstract: The circuit comprises a primary circuit (2) feeding brake motors (5) and (7) and a secondary circuit (3) feeding a brake motor (9). In normal operation a valve (11) isolates the brake motor (22) from the secondary circuit (3). The pressure in the primary circuit then controls the pressure prevailing in the brake motor (22) with the aid of a pressure balancing device (25) installed between the feed lines of the brake motors (7 and 22). In the event of the failure of the primary circuit (2) the valve (11) establishes communication between the brake motor (22) and the secondary circuit (3) to effect the braking of the wheel associated with the brake motor despite the fact that the balancing device (25) is put out of action in this situation. Application to a brake circuit equipped with an anti-wheel-lock device.

Abstract: The circuit according to the invention is provided with a wheel anti-lock device of the type with independent control of the front wheels and control of the back wheel brakes by way of the pressure in the brake associated with the back wheel having the lowest resistance to skid. It comprises a safety device protecting the normal functioning of the circuit against escapes from the release valves (18, 18', 18") of the isolation-release electrovalves (11, 11', 11") and against the failure of a single pump (28) which resupplies the circuit directly from the reservoir (3) of the tandem master cylinder (2). A pressure regulator (7) avoids reactions on the brake pedal (2). The circuit may be applied to an anti-locking brake circuit having increased compactness and reliability.

Abstract: This distributor comprises an external element (3) mounted rotatably in a housing (1) and an internal element (10) mounted rotatably in the external element and capable of a limited rotation on either side of a neutral position. The external element (3) has inlet passage ports (17a), (17b) communicating with a fluid pressure source (5), at least one pair of distribution ports (19, 20) communicating selectively with one of the two opposite chambers of a drive means (8), and return recesses (18, 31) communicating permanently with the tank (15). The internal element (10) has longitudinal grooves (16) which, in the neutral symmetrical position, throttle the distribution ports in the same proportion and also ensure permanent communication between the inlet ports and some of the return recesses.

Abstract: The device comprises a pilot slide (27) controlled by a pressure differential (P-P') determined by an electromagnetic pilot valve element (43) located in a return circuit to a tank (7) which is common to both the hydraulic installation and a branch pipe (8). The device preferably includes an isolating valve (40) connected to the pilot valve element (43) so as to isolate a pilot chamber (30) in the event of a failure of the electromagnetic actuator.

Abstract: Hydraulic pressure servo-regulator, intended to provide a hydraulic fluid pressure corresponding to a given electrical signal, comprising an electromechnical device (10) connected to a valve mechanism (12) of a high-pressure fluid circuit (38), characterized in that the electromechanical device (10) comprises a geared motor, the valve mechanism (12) comprising a spool valve (44) connected to the geared motor (10) by way of a spring (58).

Abstract: Hydraulic booster device intended to be arranged in parallel with a primary actuation circuit between an actuator mechanism and a receiver, the device comprising an electromagnetic valve mechanism (10) arranged between an actuator (12) and a pressure-fluid source (16), the actuator (12) comprising a piston means (56, 66, 92) displaceable under the effect of the pressure-fluid and intended to actuate the receiver independently in response to an electrical control signal supplied to the valve mechanism (10).

Abstract: The solenoid valve comprises a mounting base (1) having an inner projecting part (7) supporting an upper piece (14) via a tubular supporting piece (13), the assembly being joined together by way of a cover (21) crimped (26) on the mounting base. The plunger structure comprises a core of magnetizable material (31), sliding in a bore (15) in the upper piece (14), and a tubular extension piece (27) made of non-magnetic material and sliding in a bore (10) in the projecting part (7) of the base, inserts of various shapes (36; 41) being arrangeable in the base (1) and in the upper piece (14).

Abstract: Hydraulic booster comprising a housing provided with a bore inside which there is slidably mounted two pistons each associated with a respective pressure chamber intended to be connected to a respective brake circuit; an actuating piston slidably mounted inside the bore and intended to be displaced by a brake pedal, displacement of the actuating piston being capable of causing displacement of the two pistons; and two valve mechanisms each associated with a respective brake circuit and intended to control the flow of pressurized fluid from a respective source to the brake circuit, characterized in that the two valve mechanisms are arranged parallel to the bore and are intended to be actuated simultaneously by the actuating piston.

Abstract: Hydraulic assistance device comprising a housing (10) provided with a bore (12) in which a piston mechanism (30, 42) is slidably mounted, which mechanism is displaceable by a brake pedal between a first position linking a first chamber (38, 56), connected to a brake circuit (60), with a low-pressure reservoir and isolating this chamber (38, 56) from a high-pressure fluid source (66), and a second position isolating the chamber (38, 56) from the low-pressure reservoir and linking it with the high-pressure source (66), the piston mechanism (30, 42) being displaceable by the brake pedal in the event of failure of the high-pressure circuit (66) thereby producing pressure increase in a second chamber (69) connected to the brake circuit (60), characterized in that the working area of the piston mechanism (30, 42) is equal to the cross-section of the bore (12).

Abstract: In a branch hydraulic line (6.sub.a, 6.sub.b) upstream of the distribution servovalve (1) of the assisted steering system, a valve mechanism with electromagnetic control (10) is situated, which comprises a valve member biased by an electromagnetic actuator (16) having two states, energized and unenergized, which is controlled by a switch (20.sub.a, 20.sub.b) actuable by the lever (21) of the gear changing mechanism of the vehicle so as to close the branch line (6.sub.a, 6.sub.b) during engagement of the parking gears (first and reverse) and thus to obtain maximum hydraulic assistance power, the assistance power being reduced during other conditions of use (driving along the road) of the vehicle.

Abstract: In a bridging circuit (6.sub.a, 6.sub.b) connecting the two opposing chambers ( V.sub.1 V.sub.2) of the hydraulic assistance actuator (5), a valve seat (11) is interposed which may be closed selectively by a valve member which is biased by an electromagnetic actuator (14) having two states, energized and unenergized, which is controlled by at least one switch (18.sub.a, 18.sub.b) actuatable by the lever (19) of the gear changing mechanism of the vehicle so as to close the bridging circuit (6.sub.a, 6.sub.b) when the parking gears are engaged (first and reverse) in order to obtain maximum hydraulic assistance power, the assistance power being reduced during other conditions of use of the vehicle (driving along the road).

Abstract: Hydraulic assistance device, incorporating a casing (10) provided with a bore (12) in which first piston means (16, 18) is slideably mounted, the piston (16, 18) being able to move under the effect of the actuation of a brake pedal between a first position allowing communication between a first chamber (72) which is connected to a braking circuit (70) and a low pressure reservoir (40), and isolating this chamber (72) from a source of high pressure fluid (76), and a second position isolating the chamber (72) from the low pressure reservoir (40) and causing it to communicate with the high pressure source (76), the device also incorporating a second chamber (38) formed in the casing (10), the communication between the first chamber (72) and the reservoir (40) incorporating a second bore (52) in which a control piston (54) of second piston means (54, 60) is slideably mounted, incorporating a bore (56), the first piston having a bore in which a plunger (31) is slideably mounted, the plunger (31) joining the first

Abstract: In a body (3) enclosing at least one brake-pressure control device actuated manually (1, 1') there is mounted an isolating and pressure-reducing solenoid valve mechanism (18, 24) which selectively establishes communication between a brake circuit (22) and, on the one hand, the fluid outlet (8) of the device (1) and, on the other hand, a reservoir (10), the solenoid valve mechanism comprising a discharge end (30) emerging in an extension (33) of the reservoir (10).

Abstract: The device for controlling flow (10) situated in a branch hydraulic line (6), comprises a piston slide (15) sliding a bore (14) into which an inlet passage (36) and an outlet passage (20, 21) open, the slide forming with the outlet passage (21) a modulable restriction (s); the device comprsies a fluid passage between the inlet and outlet passages which includes a first portion (32, 33, 34), formed in the slide (15), and a second portion (19, 24, 23, 22) which is formed in the body (13) and is closed selectively by a spring biased (27) valve member (26) and the plunger (28) of an electromagnetic control member (9) piloted by an electrical signal which is a function of a significant parameter, for example the speed of a vehicle for the assisted steering of a vehicle.

Abstract: The servo device for controlling flow (10) situated in a branch hydraulic line (6), incorporates in a body (11) an inlet passage (12) and an outlet passage (9) connected by an intermediate passage (13) forming a seat (14) for a valve component (15) which is pushed against its seat by a spring (26) and by an electromagnetic actuator (16) via a push-rod (23) which is slidingly sealingly mounted in a bore (22) between the intermediate passage (13) and an internal chamber (19) which is connected to the inlet passage (12).

Abstract: The device for controlling pressure (20) situated in a branch hydraulic line, comprises a distributor slide (23) which slides in a bore (22) into which an inlet passage (27) and an outlet passage (28) open, the slide forming with the outlet passage a restriction which can be modulated selectively, the slide having an internal passage (32, 30, 29) which is provided with a restriction (30) which establishes permanent communication between the inlet passage (27) and a pilot chamber (24), a passage (36, 37) communicates with the outlet passage (28) which opens into the pilot chamber (24) through a valve seat (35) which may be closed selectively by a valve member (38) which is controlled, as a function of electrical control signals, by an electromagnetic control component comprising typically a main coil (42) and a secondary coil (45) mounted on a non-magnetic support (39) which is firmly fixed to the valve member (38).

Abstract: The invention concerns a hydraulic amplifier for a braking system incorporating a body (10, 110), a first component (18, 124) capable of being displaced in the body (10, 110) under the effect of the operation of a brake pedal, between a first position causing a first chamber (16), joined to a braking circuit, to communicate with a low pressure reservoir (44, 138), and isolating this chamber (16) from a high pressure source (32, 130), and a second position isolating the chamber (16) from the low pressure reservoir (44, 138) and causing it to communicate with the high pressure source (32, 130), characterized in that it incorporates a second chamber (12, 112) formed in the body (10, 110), a circuit (42) causing this second chamber (12, 112) to communicate with the low pressure reservoir (44, 138), and a valve means (34, 116) responsive to the pressure of the high pressure source (32, 130) normally closing this circuit under the effect of the pressure of the high pressure source (32, 130).