Abstract: A declutching device comprises an hydraulic actuator, a preloading spring for permanently biassing the movable member of the actuator towards its retracted position with respect to the fixed member of the actuator, and a retaining ball which is adapted to retain the movable member in a withdrawn position with respect to the fixed member during and prior to assembly. A feeler projects outwardly from the hydraulic actuator, so as to be displaced by the clutch while relative axial movement of the clutch and declutching device towards each other is taking place during assembly. The feeler is mounted for movement between a fitting position in which it allows the retaining ball to carry out its above mentioned function, and an operating position in which the retaining ball is no longer effective. The invention is applicable to clutches of the pull-off type, especially for motor vehicles.

Abstract: A clutch friction wheel, especially for a motor vehicle clutch, comprises two coaxial parts which are mounted for rotation of one with respect to the other about a common axis, with an annular damper between them. The damper comprises two rings one of which is in contact with a surface of the first coaxial part, while the other is in contact with a surface of the other part. The two rings of the damper are joined together by elastic members. The rings of the damper are disposed in a groove formed in one of the two coaxial parts, and they are divided into at least two ring segments, each of which includes an equivalent element of each of the two rings.

Abstract: A clutch friction wheel of the kind which is in three parts, especially applicable to industrial vehicles, comprises a friction disc fixed to a damper plate, and guide rings fixed to a support ring which is arranged between the damper plate and the hub. Firstly, the friction disc, damper plate, guide rings, support ring and damping device constitute a first sub-assembly in which the guide rings are secured directly to the support ring on their inner perimeter; secondly, a predamper device acting between the support ring and hub constitutes with the latter a second sub-assembly, in which the predamper device is arranged outside the guide rings on one side of the latter, while a retaining abutment element is disposed axially on the hub on the other side; and thirdly, a mating coupling is arranged between the predamper device and the support ring.

Abstract: A clutch has two friction wheels, a common hub, and a predamper, one of the friction wheels having an elongated hub with external teeth which mesh without clearance with teeth formed in the hub of the other friction wheel. The elongated hub is coupled in rotation to the common hub of the clutch through teeth which mesh after a circumferential clearance between them has been taken up. The predamper and the common hub together form a subassembly, and a retaining ring is located axially on the common hub so that the retaining ring and the predamper together retain the elongated hub on the common hub. The predamper is coupled in rotation to the elongated hub by an axially releasable mating coupling.