Friction clutch with automatic compensation for wear

For use in a power train, a friction clutch which is subject to wear and comprises:

• a housing having a wall and being rotatable about a predetermined axis;
• a pressure plate rotatable with and having limited freedom of axial movement relative to said housing;
• at least one diaphragm spring disposed between said wall and said pressure plate and being arranged to bias said pressure plate axially of said housing and away from said wall with a force which tends to vary as a function of the extent of wear upon the friction clutch, said at least one diaphragm spring including an energy storing device having an annular portion spaced apart from said axis, prongs extending from said annular portion toward said axis, and prestressed hairpin-shaped tongues forming part of said annular portion and arranged to bias said at least one diaphragm spring against said housing, said tongues having pairs of portions spaced apart from each other in a circumferential direction of said housing and at least one of said prongs being disposed between said pairs of spaced-apart portions of at least some of said tongues;
• and
• means for compensating for wear upon the friction clutch by maintaining said diaphragm spring at an at least substantially constant stress condition including means for moving said at least one diaphragm spring in the direction of said axis from said wall toward said pressure plate.

For use in a power train, an engageable and disengageable friction clutch which is subject to wear and comprises:

• a housing having a wall and being rotatable about a predetermined axis;
• a pressure plate rotatable with and having limited freedom of axial movement relative to said housing;
• at least one diaphragm spring disposed between said wall and said pressure plate and being arranged to bias said pressure plate axially of said housing and away from said wall with a force which tends to vary as a function of the extent of wear upon the friction clutch, said at least one diaphragm spring including an annular portion spaced apart from said axis and having a radially inner marginal portion, prestressed hairpin-shaped resilient prongs extending from said annular portion toward said axis and permanently reacting against said housing, and hairpin-shaped tongues forming part of said annular portion, extending from said marginal portion, radially inwardly toward said axis and arranged to bias said at least one diaphragm spring against said housing during disengagement of the friction clutch;
• and
• means for compensating for wear upon the friction clutch by maintaining said diaphragm spring at an at least substantially constant stress condition, including means for moving said at least one diaphragm spring in the direction of said axis from said wall toward said pressure plate.