GB831664A - Improvements in or relating to friction clutches - Google Patents

Abstract

831,664. Friction clutches. FRANCAISE DU FERODO S.A. June 20, 1957 [June 20, 1956; June 14, 1957], No. 19506/57. Addition to 753,732. Class 80 (2). In a motor vehicle friction clutch according to the parent Specification, wherein over-run torque is limited by a friction slip-coupling which is in series with the driven main clutch disc 16 and in parallel with a forward positive ratchet clutch, the torque limiting coupling now comprises friction shoes 20 which, in the forward drive direction, are expanded with a non-slip self-tightening action into engagement with a final output drum 18 by a cam 23 fast to the freely-mounted driven main clutch disc 16, whilst on over-run the shoes 20 are expanded only by springs 22 for slip limited torque transmitted from the shoes through the cam 23 to the clutch disc 16. A negative torque ratchet clutch for push starting and compression-parking comprises ratchet teeth 27 fast to the clutch disc 16 and engaging pawls 28 pivoted on the engine flywheel 12 and lifted centrifugally out of action at speeds above engine idle. In Figs. 3-5, not shown, the ratchet teeth have centrifug 1 masks covering them during normal running to prevent sudden engagement of the ratchet clutch if the engine stops; the springs 22 seat on heat-insulating washers; and the friction material is carried on the drum 18 instead of on the shoes 20, whereby heat is conducted to the shoes rather than the drum. In Figs. 7 and 8 the main clutch is of the Gravina type (Specification 586,910) with its pressure-plate anchored to the flywheel by tangential spring strips.