GB384816A - Transmission gearing - Google Patents

Abstract

384,816. Motor-vehicle driving-gear. ALVIS CAR & ENGINEERING CO., Ltd. and CLARKE, G. T. SMITH-, Holyhead Road, Coventry. Dec. 24, 1931, Nos. 35665 and 35666. [Class 79 (ii).] Transmission gearing wherein the driving shaft is connected with the driving element of a fluid coupling and one element of a planetary train, the driven element of the fluid coupling is connected with a further element of the planetary train, and the remaining element of the planetary train is connected with the driven shaft, is combined with supplementary gear whereby one or more changes of ratio or reverse drive can be effected. The fluid coupling is preferably of the F÷ttinger type, wherein a casing 2, caused to revolve with the crank shaft 5<1>, is formed with internal cups 3 which act through the fluid medium on cups 4 connected with an internally toothed annulus 6. An extension 5 of the crank shaft forms or carries the sun wheel of the planetary assembly, and the planet wheels 8 engaging the sun wheel and the annulus 6 are carried by a member 9 mounted on the driven shaft 10, which passes through a gland 11. A variable-speed gear is thus provided in which the ratio depends upon the degree of slip between the cups 3, 4, which is determined by the load on the driven shaft. If desired, the planetary gear may be located outside the casing 2. As shown, the supplementary gear comprises an epicyclic reversing gear in which the sun wheel 17 is mounted on the shaft 10, the internally toothed annulus 18 is mounted on the shaft 19 communicating with the road wheels, and the intermediate planet wheels 16 are carried by a drum 15. This drum is normally caused to revolve with the shaft 10 by means of spring-pressed clutch members 13, thus imparting a direct drive to the shaft 19. Operation of the pedal 20 disengages these clutch members through the action of links 21, and the application of a brake band 14, either by the further depression of the pedal 20 through suitable mechanism (not shown) or else by a separate control, causes a reverse drive to be imparted to the shaft 19. In a modification, the device is combined with a change-speed gear of standard type for use when the range provided by the device itself is inadequate, and in this case it is necessary to bring the shaft 10 to rest when changing gear ; this may be effected by a band brake acting on a drum on the shaft 10 and actuated by any suitable control, but preferably by a trigger on the gear lever which also serves to lock it in its various positions. If desired a clutch may also be provided between the crank shaft 5<1> and the sun wheel 5, as described in Specification 385,112, [Group XXIV]. The supplementary gear may be operated by pneumatic, hydraulic, electric or other means.