GB206059A - Improvements in or relating to variable-speed gearing - Google Patents

Abstract

206,059. Johnson, J. W., (Johnson, W. T.). Jan. 30, 1923. Variable-speed gearing comprises a spherical surface C coacting with a ring of friction rollers 21 the axis of which ring is moved angularly to change the velocity ratio. The rollers 21 turn freely in separate carriages 20 which slide radially being thrust ootwards by spring-pressed wedges 19. The frame B supporting the rollers 21 has an inner spherical surface 16 driven from an inner invariable ring of rollers 15 carried by a spherical boss A secured to a driving-shaft 1. The speed at which the sphere C is driven is varied by changing the obliquity of the frame B which is done by means of a conical pedestal 28 which can be turned relatively to a fixed oblique eccentric 23 by a manually-operated worm 31. In the arrangement shown, the sphere C is coupled to the internal gear 34 of an epicyclic train, to control it. The sun gear 32 of this train is secured to a driven shaft 2, and the planet gears 33 are carried by the shaft 1. The speed of the shaft 2 varies on both sides of zero. For safety, an automatic centrifugal friction clutch is arranged between the shait 1 and the boss A. This comprises two collars 6 sliding on feathers and pressing into action two multiple-plate clutches 11 which transmit power to the wedge supports 9 of the inner rollers 15. These collars are thrust towards one another by rings of loose centrifugal wedge-blocks 12 against the action of a medial spring 7.