Abstract: A diaphragm spring for use in a motor vehicle clutch of a variable pitch drive pulley is disclosed. The diaphragm spring is of the type comprising a Belleville washer peripheral portion and a central portion divided into radial fingers separated by radial slots. Apertures alternate with the roots or radial outer ends of the radial fingers and open radially into the slots. These apertures consist of relatively larger area main apertures and relatively smaller area intermediate apertures. The radially outer edges of all the apertures lie along the same circumference of the diaphragm spring. The diaphragm spring is devoid of ribs. The diaphragm spring is rigidified along the circumference by the extra material formed around the smaller intermediate apertures, while maintaining a peripheral portion of constant radial extent throughout.

Abstract: A clutch mechanism is concerned in which the retaining lugs (28) which link to the cover (10) the retaining ring (26) which ensures that the diaphragm (11) is secured to the cover (10) have come in one piece with this retaining ring (26).According to the invention, each retaining lug (28) of the retaining ring (26) is fixed on the cover (10) between, for example, one or two transverse shoulders (36) which said retaining lug possesses for this purpose on a first side of the cover (10) and an end (34) which is folded back to bear against the cover (10) on the other side of the latter.Application, in particular, to diaphragm clutch mechanisms for motor vehicles.