Friction clutch for automotive vehicles

Claim 1

A friction clutch comprising a flywheel, a pressure plate axially movable but not rotatable relative to the flywheel to form a driving member of the clutch as a unit, a rotatable entrainment disc mounted on a rotatable shaft to form a driven member of the clutch, the entrainment disc including a clutch hub splined to the rotatable shaft and at least one plate member fitted to slide on the hub and disposed between the flywheel and the pressure plate to be clamped at the outer region by the flywheel and the pressure plate in engagement of the clutch, at least one damper means of elastic material anchored at one end to the hub and at the other end to the plate member to permit a torsion to be developed between the hub and the plate member in accordance with the elastic characteristic of the damper means, the damper means including a cylindrical external face, a through-bore concentric to the external face, and a pair of end faces surrounding opposite ends of the bore; a pair of retainer members located, respectively, at said end faces, each retainer member including a central projection extending with close fit into the bore to support the damper means, at least one of the retainer members having an outer flange portion concentric with the central projection, the flange portion including an internal face of larger diameter than the diameter of the external face of the damper means in an uncompressed state to form an annular clearance of uniform radial thickness therebetween, said clearance maintained by support of said damper means by said central projections; the clearance being sufficiently large to allow the damper means when compressed to expand without resistance traversely of the direction of compression during a first stage of the compression period, the clearance being small enough that the external face of the damper means contacts the internal face of the flange portion to resist further outward expansion of the damper means and lessen the ability of the damper means to further expand during a subsequent stage of the compression period, said retainer members being disposed in non-contacting relationship during the entire compression period.