GB674600A - Improvements in centrifugal clutches - Google Patents

Abstract

674,600. Centrifugal clutches. KREIS, F., and S.I.B.A. SOC. ITALIANA BREVETTI AUTOMOBILISTIC AR.L. Sept. 14, 1950 [June 20, 1950], No. 22621/50. Class 80 (ii). A centrifugal clutch contains two members which, when rotated relatively to each other, increase a spring force acting on a pressure plate of the driving clutch part and tending to disengage the frictionally engaging plates. The relative rotation of the two members takes place only when the clutch is under load, so that the engagement and disengagement of the clutch plates, produced by the movement of' weights under the influence of centrifugal force, occurs at a higher rotational speed than when it runs free. The clutch is particularly intended for use as the starting clutch of a heavy vehicle. A driving shaft 1 carries a drum 2 on which are fixed clutch plates 4 engaging driven clutch plates 12 on a .further drum 14. The drum 14 is mounted for limited, rotation on a drum 16, fixed to the driven shaft 15, containing a plate 17. In the Figure, the plate 17 is urged to the left by springs 23, 24, while it is constrained for rotation with the driven drum 16 by grooves 18. Inclined faces 17<SP>1</SP> on the plate 17 co-operate with inclined faces 19 on a ring 20., which is seated on bolts 21 guided in the frontal face of the drum 16. The bolts 21 abut a thrust bearing 22 separating the driven part of the' clutch from a pressure plate 11 in the driving clutch. part. Axial thrust from the springs 23, 24 is transmitted through the plate and rings 17, 20, bolts 21 and thrust bearirig 22. to the pressure plate 11 which is thereby urged so that the friction discs 4, 12 are disengaged. Weights 5 in the driving drum 2 and weights 27 on the driven drum 14 are urged inwards by springs 6, 28 but move outwards. under centrifugal force to engage the friction discs 4, 12, the engagement produced by the movement of the weights 5 preceding that by the weights 27. If the clutch is rotated initially with the driven shaft under load, the drum 14 rotates relative to the drum 16 fixed to the driven shaft and the interaction between the inclined faces 17', 19 increases the compression of the springs 23, 24. Complete engagement of the discs 4, 12 is thus not possible until the weights 5 are rotated at a higher speed than would produce engagement if the clutch, were running free. The weights 27 allow the clutch to be engaged on rotation of the driven shaft 15 if the driving shaft 1 is'stationary, so that a vehicle in which the clutch is mounted can be started by towing.