Abstract: The torque sensor comprises first (11) and second rotary structures coupled respectively for rotation to first (5) and second (4) coaxial rotary members mutually coupled by a dead-travel resilient coupling (6), the rotary structures having adjacent zones each formed with a series of angularly spaced optical windows (13, 14) arranged to cross a light path, two corresponding windows belonging to each series being in partial overlapping relationship in the light path when the rotary members are in a relative neutral position.

Abstract: The piston of the generator (6, 8) has a smooth lateral surface and cooperates in sliding sealing engagement with a pair of seals (9a, 9b) fixedly mounted in annular grooves formed in the interior surface of the single bore (2) of the tubular body (1) of the generator. The bore opens at either end of the body and comprises, in its interior surface, at least one longitudinal groove (17) extending over the entire length of the bore, the bore being closed at one end by an obturator element (4) fitted onto the body (1).

Abstract: The system for generating braking pressure, consisting of a pneumatic assistance servomotor (2) mounted so as to overhang on a master cylinder (1) which it actuates by a tubular pullrod component (14) in which extends the control pushrod (11) of the distribution valve (10), incorporates a pre-assembled unitary valve assembly (10) screwed to the end of the tubular pullrod component (14) so as to connect the latter to the movable piston wall (6) of the servomotor, the valve (10) being linked by a cylindrical flexible sealing component (50) to a central annular zone (19) of the front wall (4) of the servomotor casing which is closed by a labyrinth filtering structure (80) with draining means (86).

Abstract: The distributor comprises a star-shaped rotor (2) arranged between two concentric components which are spaced axially and are fixed in rotation to a second valve portion (60); a C-shaped centering return spring (40) is arranged around the rotor (2) and cooperates, by its facing ends, with a projection (100) of one of the arms (10.sub.1) of the rotor and with adjacent projections of the second valve portion.

Abstract: The distributor (10), typically with a star-shaped rotor in a discoid stator, comprises a reaction device (11) advantageously integrated in the distributor and providing the actuating member (17) of the distributor with a reaction opposite to the actuating torque exerted on this actuating member and proportional to the power-assistance force supplied by a jack (12) controlled by the distributor (10). A regulating valve (30, 31) is associated with the reaction device (11), being typically located upstream of the latter, and is put into effect when the reaction force applied by the reaction device reaches a maximum predetermined value, in order to limit the reaction force to this predetermined value.

Abstract: The distributor (10, 11), typically with a star-type rotor in a discoid stator, incorporates a valve means with an OR logic function (5, 5') of preselection of the direction of the reaction (22, 23) to be applied to the input component as a function of the relative displacement between the primary and secondary components of the distributor, formed in one piece with the distributor and consisting of pairs of edges cooperating between two cavities (39a, 39b) of the stator (28, 30) and a cavity (44) of the rotor (31) advantageously formed in a reaction arm (41) of this rotor and permanently communicating with the source of pressure (14) of the distributor via a restriction (4) which can be externally modulated. The restrictions (5, 5') providing the OR logic function come into operation first, before the actual distribution restrictions (1, 2, 3; 1', 2', 3') of the distributor supplying the assistance actuator (19).

Abstract: The distributor comprises a primary rotating member having a prolongating portion (11) surrounding coaxially the primary rotating member (5) and forms a seat for at least a C-shaped rection spring (27) the ends of which (48) resiliently been upon a radial finger (37a) secured to the primary member and cooperate in engagement with aperatures (43a) formed in the prolongating portion (11) of the secondary member, thus forming a lost-motion coupling between the two members.

Abstract: The mechanism comprises two movable cylinders (7, 9) which are sealingly slidably mounted on respective stationary pistons which are firmly carried by rods (3, 4) mounted in a stationary casing (1). One of the cylinders (9) supports a rack (11) which meshes with a control pinion (12) and which is centrally connected to the other cylinder (7) and to output members (21) which are intended to be connected to a linkage for the steerable wheels and which pass through an opening (22) formed in a lateral wall of the casing (1).

Abstract: The power assisted steering mechanism consists of a rack body (20) guided and confined to slide in the steering casing (10) and joined centrally through the lateral wall of the casing (10) by shaft components (31), to a steering linkage of a vehicle, the opposite ends (23) of the rack being joined by rods (51) to pistons (50), single or double acting, each sliding in a cylinder (41) attached to the end (11) of the casing (10) in the extension of the latter.

Abstract: The power assisted steering system, particularly of the type with central output, incorporates a body (10) forming a housing for a cooperating pinion (12) and rack (11) assembly. The rack is guided in the central portion (10.sub.1) of the body and is joined by a rod (40) to at least a first piston (30a) movable in a cylinder consisting of a component in the shape of a cylindrical bell (20a, 20b) attached to one end of the body (10) and itself consisting of a rolling membrane (31) joined at its periphery to the component in the shape of a bell, and of a tubular support component (24) fixed to the rod (40) and coaxial with the latter. Also described are variants with a twin circuit incorporating a second piston carried by the rod and sliding so that it is sealed relative to a central stationary component passing longitudinally through the rack.

Abstract: Situated between the opposite end walls (13, 13') of a fixed steering casing (10) is a hollow rod (14) carrying a fixed piston (16) on which a cylinder assembly (50, 51) slides, on which is elastically mounted, through the intermediary of elastic components (34), a rack block (30) meshing with a pinion (20) which is coupled to the output component of a distribution valve (40).

Abstract: The cooperating double-acting piston/cylinder assistance assembly of the rack (20) incorporates a cylinder (24) firmly fixed to one end of the rack, in the extension of the latter and a stationary piston (40) fixed to one end of a hollow rod (42) whose other end (43) is fixed centrally in the steering casing (10), the hollow rod enclosing two separate fluid passages (45, 47) for supplying the chambers which are in opposition (46, 48), on each side of the piston (40), with actuating fluid under pressure coming from a distribution valve (30) mounted in the casing (10).

Abstract: The mechanism incorporates at least one assistance unit consisting of a fixed piston (44) supported by a hollow rod (43) and of a cylinder (32) housed in a bore (30) of the rack (11), the chambers (60, 61) being supplied through separate passages (62, 63) extending through the hollow rod (43). The mechanism, advantageously of the type with central output and with a double circuit, incorporates a double circuit distribution valve mechanism (20) for supplying selectively the pairs of chambers (60, 61) on each side of the pinion (12) of the rack (11).

Abstract: Two pistons (5, 8) are mounted in the same casing (1) so as to slide in a sealed manner, the two pistons (5, 8) being firmly fixed to one another and having corresponding actuating chambers (21, 22; 23, 24) which are separated from one another and are supplied sequentially by two distribution valves (A, B) which are situated in the casing (1) and are actuated by the input shaft (14). The second piston (8) is formed by an extension (7) of the first piston (5) and its corresponding actuating chambers (22, 24) are formed in the piston structure (5, 8) and by a housing (4) in the casing (1), respectively, the housing (4) being coaxial with the main housing (3) for the first piston (5). The two valves (A, B) are advantageously of the type having a star-shaped rotor (30, 40).

Abstract: The distributor, typically one having a star-shaped rotor in a disc-shaped stator, incorporates two components, primary and secondary, defining two parallel distribution circuits (10, 10') controlling an assistance actuator (V) and incorporating, in each circuit, three variable restrictions (1-3 or 1'-3'), together with, advantageously, two other parallel reaction circuits (20, 20') with two restrictions in series (4, 5 and 4', 5'). The chamber (V.sub.1, V.sub.2) of the assistance actuator (V) are joined to the distribution circuits (10, 10'), respectively, between the second (2, 2') and third (3, 3') variable restrictions which create the differential assistance pressure, the central point of the distributor being determined by the first (1, 1') and second (2, 2') variable restrictions.

Abstract: The distributor comprises a primary member, a secondary member coaxial with the primary member and having a part (3') at least partially surrounding a part (2') of the primary member, a distribution valve coupled to the primary member, and at least one deformable resilient device (4) having at least one pair of abutment surfaces (5) cooperating with the first (20) and second connection members connected to the primary and secondary members in order to hold them in a relative centered position of rest, the resilient device (4) being mounted so as to be sealingly slidable by opposite annular side faces in an annular cavity (32) formed in a member rotationally fixed to the secondary member and shaped to define in that cavity an internal chamber (6) and an external chamber (7), which are separate and whose volumes are inversely variable, means (8) being provided to direct a fluid under modulable pressure into at least one of these chambers.

Abstract: The electrical power steering mechanism comprises an electric motor (30) whose stator is mounted in the steering box (10) and whose rotor (32) is disposed coaxially around a cylindrical portion of the rack structure (40) provided with helicoidal grooves (41) and forming a screw of a ball circuit mechanism in cooperation with a nut structure (33) having helicoidal grooves (35) and fastened to the rotor (32), the drive pinion (20), typically a Novikof profile globoidal pinion, meshing directly with the ball circulation helicoidal grooves (41) of the rack (40).

Abstract: The caliper (52), in the form of a closed frame surrounding the fixed support (50), incorporates at least one axial reinforcing member (3) joining two axially separated zones (1, 2) of the caliper by passing through them and extending radially beyond the periphery of the disc (53). The reinforcing member incorporates a head (4), which is received within a complementary recess in the first zone of the caliper (1), and a threaded end cooperating with first and second locking and tightening elements, cooperating with each other (for example a locking nut 5 and a removable washer 10) of which the first elements is lockable on the threaded end so as to give, together with the second element, a predetermined tension to the reinforcing member, the second element being capable of being selectively disengaged to allow the reinforcing member to be separated (by tilting or longitudinal displacement) from the second zone (2) of the caliper.

Abstract: The distributor defines two parallel fluid circuits (15, 16) each including serially arranged first (1;1') and second (2;2') valve means actuated by the primary control member (OP) of the distributor, two distribution lines (17, 18) for selectively supplying the chambers of an assistance motor-actuator (12) derivating from said circuits (15, 16) downstream the primary valve means (1;1'), and two additional return valve means (3;3'), upstream said second valve means (2;2') coupled to the piston (13) of the actuator (12) to form a restriction in the return circuit from the actuator chamber in relieved condition and thus create an over-pressure enabling effective return of the actuator to neutral position after return of distributor to rest condition.

Abstract: The device comprises a hydraulic operating actuator (5), associated with a friction element (4) and capable of being operated by a liquid under pressure to bring the friction element into frictional contact with the component to be braked (2); and a pneumatic actuator means (10), incorporating a hydraulic chamber (20), joined to the hydraulic actuator (5), and a pneumatic chamber (14) capable of being joined to a source of gas under pressure, the two chambers being separated by a movable wall structure forming a piston, the hydraulic chamber (20) being at least partially defined by a flexible elastic envelope (21) arranged in the immediate vicinity of the hydraulic operating actuator.