Abstract: The friction clutch comprises a friction disc, a pressure plate (1), a cover plate (2), a diaphragm (3) working between, firstly, the cover plate (2) and secondly the pressure plate (1), the said clutch also including a wear compensating device comprising ramps (11) disposed circumferentially and adapted so as to be driven in rotation by means of a set of teeth (18) which they carry at their periphery and with which a tangentially disposed worm (13) cooperates, a ratchet wheel (20) for driving the worm (13) in rotation being provided and rendered operational by wear in the friction liners when the clutch is engaged, together with non-return catches (36) for preventing the worm (13) from turning in the direction opposite to that in which it is driven in rotation by the ratchet wheel when it is operational, the worm (13), the non-return catches (36) and the ratchet wheel (20) being carried by a support (12) fixed to the cover plate (2): the ratchet wheel (20) of the worm (13) is controlled by the diaphragm (3).

Abstract: A torsional pre-damping device for damping the impact between a hub and a hub disc. A crown insert (20) made of absorbent material is arranged between the engaging teeth (18) and the engaged teeth (19) of the loose meshing portions (16) defined between the disc and the hub.