Abstract: The invention concerns a hydraulic, in particular clutching, actuator for receiving control data from a hydraulic circuit in the form of pressure variations. The concentric-type actuator (8) for hydraulic control comprises a fixed part (9) consisting of an external body (21) and a guide tube (22), both cylindrical and coaxial, and a piston (11) mounted sliding coaxially to the fixed part (9) and defining therein a chamber with variable volume (13) designed to be connected to the hydraulic control hydraulic transmitter, the external body (21) comprises on its internal face (35) a groove wherein is inserted a radial edge (31) with which the guide tube (22) is provided at one of its ends and which partially constitutes the variable volume chamber (13) bottom.

Abstract: A transmitter for hydraulic control controlled by a controlling member including a hydraulic chamber having a piston mounted thereto by means of a joint. The hydraulic chamber defines a pressure chamber with variable volume connected to a hydraulic line. A reservoir is connected to the pressure chamber via a passage. A mechanism for preventing the fluid from returning to the reservoir and a mechanism for transmitting the control member movement to the piston is also provided. The hydraulic chamber is extends along its axis defining a reserve volume and is adapted to receive the piston and containing hydraulic fluid up to a level sufficient for the joint to be immersed therein. The hydraulic chamber and the reservoir volume are arranged in a single housing. The transmission mechanism includes of two parts. The first part is internal to the housing and connected to the piston and the other part is external to the housing.

Abstract: The friction clutch has on the one hand a clutch engagement device comprising a diaphragm (3) and on the other hand a linkage (80), an actuator (50, 60, 70, 90, 91) for controlling the said linkage, and an adjustment device (10), for compensating for the wear on the friction linings (7) the actuator has an electric motor (50), a mechanical transmission (60) with an input element (51) and an elastic assistance device (70) bearing on a fixed part (91, 66) and on a movable part (61) forming a nut for cooperating with the output shaft (51) of the electric motor, the movable part (61) forms the output element of the mechanical transmission (60) while being able to act on the linkage (80) while the device for taking up wear (10) is mounted inside the declutching device.

Abstract: A master cylinder for a motor vehicle clutch is coupled to the clutch pedal by means of a fastening and articulating device comprising a ball which is mounted pivotally in a ball housing. The ball housing is in the form of a tulip, the base of which has a thrust seating surface configured as a hollow spherical bowl; the petals of the tulip consist of fingers deformable axially to enable the ball to be introduced into the housing along the general axis of the housing, so as to be resiliently gripped within the housing by the fingers.

Abstract: The invention concerns a fluid pressure ram having a fixed cylindrical control chamber defined radially by inner and outer partitions, in which one axial end of the chamber is closed off by a piston which has a cylindrical housing and in which, in the retracted position of the piston, the inner partition of the chamber is received in the housing. The piston, in the protruding position, is fully disengaged axially from the fixed chamber. Two cylindrical shells provided axially in line with the chamber are provided when the piston is in the retracted position. The shells are able to slide axially with respect to the piston and with respect to the chamber so as to define, in the protruding position of the piston, an intermediate annular chamber which axially extends the fixed chamber and which is closed axially by the piston.

Abstract: An actuator, particularly for the operation of a vehicle clutch in which an annular piston (10) slides between cylinder walls (11, 12) to define an annular working chamber (20). A sealing means (15) seals the piston to the cylinder walls and an overflow chamber (26, 27) retains any fluid which leaks past the sealing means from the working chamber. A return means (28) is also provided for returning fluid from the overflow chamber when the piston is not undertaking a working stroke.

Abstract: A sealed hydraulic coupling comprises two coupling elements, each of which has an outer body, a rigid sleeve, and one part of a deformable duct which is fitted and gripped between the outer body and sleeve of the coupling element associated with it. The interior of each sleeve communicates with the interior of the associated duct part. An obturator is associated with each sleeve, which is closed by a closure member. Each sleeve is rigid and has a fluid flow port in its side wall, the end of each sleeve being closed by an end plug. The obturator of each coupling element comprises a sealing element interposed between the outer body and the corresponding end plug. One of these end plugs is fixed and carries a seating for a movable sealing ring, while the other one is movable and carries a further sealing ring. The invention is especially suitable for use with hydraulic clutch control systems for motor vehicles.

Abstract: A hydraulic master cylinder and reservoir assembly having a master cylinder body with a fluid reservoir, and a master cylinder bore with a piston assembly sealingly reciprocal within the bore. The fluid reservoir has at least a portion thereof concentric with the master cylinder bore and is sealed from the atmosphere by a rolling diaphragm, which is sealingly slidable relative to an internal surface of the reservoir allowing the volume of fluid within the reservoir to expand or contract.

Abstract: A vehicle brake pressure proportioning valve in which a stepped plunger in a stepped bore shuttles in first and second opposite directions when inlet hydraulic pressure from a master cylinder increases to a predetermined value. The aforesaid shuttling causes a ball valve, in which the ball is loaded by a spring, to close and open a bore through the plunger leading to an outlet to the brake so that during the shuttling the outlet brake pressure increases at a lower rate than the inlet pressure. Eventually the increasing inlet pressure attains another predetermined value sufficient to hold the ball valve closed against the spring loading so that the ball blocks the bore no matter which direction the plunger moves and thus the brake pressure cannot be increased any further.

Abstract: A hydraulic assisted steering device for a motor vehicle, of the type having a rotary distributor, comprising a distribution sleeve which extends a steering control member, a rotor of generally tubular shape, which is disposed within the sleeve, a torsion bar which is housed within the rotor and which has one end fixed to the rotor and the other end fixed to the steering control member, and a hydraulic circuit for generating a control value in response to an angular movement imparted to the rotor.According to the invention, the torsion bar comprises an active portion of constant section of high-resiliency steel, and two end members and ordinary steel, which are respectively engaged on the ends of the active portion and are fixed to said ends, the end members being respectively fixed with respect to the rotor and the steering control member.

Abstract: A method of braking a vehicle having an antiskid brake circuit of the type having a modulator of which the modulator chamber is connected to a set of brake actuators, and a plunger projecting into the chamber, the plunger being moved by way of a driving assembly operated by a motor driven by an antiskid control device, responsive to rotary motion of the vehicle. The curve ploting the variation with time, in the volume of the modulation chamber from the position of maximum penetration by the plunger follows substantially the same course as the absorption curve for the set of brake actuators connected to the modulator. This absorption curve represents the increase in pressure in the brake actuator as a function of the increase in the volume of fluid contained in the brake actuator.