Patent GB-847943-A (GB)
Title: Improvements in or relating to clutch operating mechanism for motor vehicles
Inventor: BLAND ALBERT NORMAN
IPC: F16D48/02
Filed: 1957-06-07
Abstract: 847,943. Friction clutches; clutch control. AUTOMOTIVE PRODUCTS CO. Ltd. May 28, 1958 [June 7, 1957; Oct. 9, 1957], Nos. 18232/57 and 31588/57. Class 80 (2). Relates to a control for a motor vehicle centrifugal clutch 10, a release collar 12 of which is moved leftward, for clutch disengagement to an intermediate normal running position for engagement controlled only by the centrifugal masses; and rightward, for engagement by the clutch springs 38 only, for towed starting and to avoid excessive slipping during slow engine running over long periods. In such a control the collar operating linkage includes levers 13, 16, connected to a rod 18 actuated as by a vacuum or pressure-operated motor 19 for clutch release at any time, and the lever 16 turns on a movable fulcrum 17 which can be held in the intermediate, centrifugal-engaging position in which a stop 20 on the rod 18 is operative to prevent rightward movement of the collar 12, by means releasable at will to permit movement of the fulcrum 17 and therefore of the clutch-release collar 12 to the spring-engaging position. In Fig. 1, a bell-crank 21, 23, carrying the lever fulcrum 17, is held against a stop 26 by a spring 24 stronger than the clutch springs 38 to maintain the normal running intermediate position. By pulling a cable control 53 or energizing a servomotor 28, the bell-crank 21, 23 is pulled away from the stop 26, permitting the clutch springs to move the collar 12 to the spring-engaging position. The servo 28 may be energized manually or automatically above a predetermined output speed or by selection of particular gear ratios, as described in Specification 847,942. In Fig. 2 (not shown), the bell-crank lever arm 21 is replaced by an arm carrying a follower co-operating with a cam-edged pivoted arm which latter carries the movable fulcrum 17. In Fig. 3 (not shown), the movable fulcrum 17 is carried by the shorter arm of a two-armed lever which latter is held against clutch spring load by a latch releasable by the trigger of a hand control, the hand grip of which is arranged to re-set the said two-armed lever to its latched position. The hand control, operated through Bowden cables, may be provided with a spring (stronger than the clutch springs) which automatically re-sets the two-armed lever and is overcome by the driver either pushing or pulling the grip continuously for clutch spring only engagement; or the hand control spring may be omitted in which case the driver's effort is required only for re-setting the twoarmed lever. In Fig. 5 (not shown), the movable fulcrum 17 is carried by a cam-edged pivoted arm cooperating with a follower mounted on a pivoted plate which latter is held against clutch spring load by a latch engaging a projection on the said plate. The control of the latch and the re-setting of the pivoted plate is similar to that of Fig. 3 (not shown). Clutches.-The clutch 10 has a driven plate 41 gripped between a flywheel 35 and a presser plate 42, the presser plate being urged towards the flywheel in opposition to springs not shown, by struts 47 acted on by pivoted centrifugal masses 43. A reaction plate 39 carrying the masses 43 is urged to the flywheel by clutch spring 38 and is movable away from the flywheel and against clutch springs by the collar 12 acting through levers 11 and links 44. In moving the collar for release the clutch springs are restrained; in the intermediate collar position the clutch springs are released sufficiently to permit engagement to be effected by masses 43 reacting on the said clutch springs; and in the rightward collar position the clutch springs are released to permit engagement by the said clutch springs alone by their direct clamping of the driven plate 41 through the reaction plate 39, stops 45, masses 43 and struts 47. Specification 847,944 also is referred to.