GB681328A - Centrifugal starting clutch for motor vehicles - Google Patents

Abstract

681,328. Friction clutches. KREIS, F., and S.I.B.A. SOC. ITALIANA BREVETTI AUTOMOBILISTICI AR.L. Sept. 14, 1950 [July 1, 1950], No. 22623/50. Class 80 (ii). A centrifugal clutch for a vehicle comprises two sets of centrifugal weights operated respectively by the driving and driven members. Secured to a cup-shaped flywheel 1 are a number of bolts 2 acting as guides for a movable pressure plate 3. Collars around the bolts contain springs 5 which urge the plate 3 inwardly, such movement being resisted by the wedging action of a ring of centrifugal weights 6 urged inwards by two tie springs and rotatable with the flywheel. Both flanks of the weights 6 have inclined surfaces which co-operate respectively with inclined surfaces on the plate 3 and on a ring 8 secured to the flywheel. Between the flywheel and the plate 3 are two ribs 9, 10 slidably keyed to the driven shaft and provided with clutch linings. The ribs are resiliently separated by the wedging action of a ring of centrifugal weights 16, rotatable with the driven shaft 15, which are provided with two pairs of inclined surfaces and are urged inwards, against a stop ring 20, by a tie spring 17. When the engine has been started the weights 6 at a predetermined low engine speed move outwardly to an extent limited by the change in inclination of the surfaces on the plate 3 and ring 8, to allow the springs 5 to move plate 3, rib 9, weights 16 and rib 10 to cause partial engagement of the clutch, the pressure depending in part on the strength of spring 17. If the vehicle is on the level, i.e. if the resistance to motion is low, this partial engagement at low engine speed is sufficient to rotate the driven shaft 15, whereupon the weights 16 move outwardly to press the ribs 9, 10 apart by centrifugal action. As the engine speed increases the weights 6 continue to move outwardly over the converging and diverging inclined surfaces on the plate 3 and ring 8, causing at first a separation. of the flywheel and plate and finally a closing in allowing complete engagement of the clutch. During the separation period engagement is maintained by the increasing pressure exerted by the weights 16. If the vehicle is being started up an incline, i.e. if resistance to motion is high, the partial clutch engagement at low engine speed is not sufficient to cause rotation of the driven shaft and this is not effected until a higher engine speed corresponding to the complete engagement referred to above. A smooth engagement at this speed is provided by the resilience of the spring 17. The vehicle may be started by towing, when rotation of shaft 15 at a speed a little above idling speed causes the weights 16 to move outwardly and engage the clutch to turn the flywheel. Since the weights 16 disengage above idling speed, sudden stopping of the vehicle does not stall the engine.