Clutch pressure plate noise reduction

Claim 1

A clutch assembly including a flywheel, a pressure plate normally engaged to rotate with the flywheel and axially disengageable in relation therewith, a friction disc interposed between the flywheel and the pressure plate, and a clutch spring operatively associated with the pressure plate whereby upon exertion of an actuation force to the clutch spring, the pressure plate will cause the interposing friction disc to be disengaged from the flywheel, wherein said clutch spring is of a generally frustoconical shaped disc having a centrally located bore adapted to surround a shaft upon which is fixed said friction disc, said clutch spring being of spring steel and slotted beginning at the periphery of said bore and extending radially outwardly to a point intermediate the periphery of said bore and the outer periphery of said frustoconical shaped disc so as to form therebetween a plurality of inwardly extending integral clutch spring fingers, each said clutch spring finger having a free end toward the axis of rotation of said pressure plate and a surface at said free end adapted to receive the actuation force, said assembly including means for modifying the natural frequencies of a majority of said clutch spring fingers to reduce resonant vibrations within the audible frequency range during actuation of the clutch whereby audible resonant vibrations caused in said clutch spring fingers as a result of the free end of each such clutch spring finger coming into initial contact with and being in rotation with a clutch throw-out bearing, will be at least substantially eliminated.