Harry Ferguson Limited

Gkn Transmissions Limited

Anthony P Rolt

Frederick J Walker

Oswald Webb

Anthony J Sheldon

Brian Colin Pagdin

A motor vehicle four-wheel-drive transmission employs an interwheel differential gear in a first axle, and solely viscous fluid coupling device in a second axle for differential transmission of drive to the road wheels of the second axle only when a speed-difference is established between the first and second road wheels, the two axles being mutually in direct driving connection through respective propeller shafts commonly driven by a change-speed box. In one arrangement of axle with a viscous fluid coupling device, a crown wheel is mounted co-axially on a housing of such coupling device from which nearside and offside half-shafts extend driven by separate sets of 'inner' annular plates interleaved with those of an 'outer' set of annular plates driven by the housing. In another similar arrangement, two separate viscous fluid couplings are used, the housings thereof being driven by a common crown wheel.

Differential drive arrangement

Viscous shear couplings for controlling the action of an interaxle or interwheel differential gear in a vehicle transmission are described. The couplings comprise a pack of interleaved annular plates which are free to float axially in an annular enclosure containing a viscous liquid. The enclosure incorporates a spring-loaded piston shiftable to vary the enclosure volume. The quantity of viscous liquid, in the range 85% to 100% of the minimum volume at ambient temperature, and the spring strength are chosen to give a predetermined pressure build-up within the enclosure with rise in temperature during shearing of the viscous liquid to tailor the torque-transmitting characteristics of the coupling to particular needs.

Viscous shear couplings

A vehicle anti-skid braking system is described wherein the brake-applying effort of a driver on a hydraulic master cylinder is assisted or opposed by a reversible servo-booster in accordance with the instant condition of an anti-lock sensor and an associated switch-over valve means. The booster incorporates two shiftable diaphragm actuators only one of which operates to assist braking effort, but both of which operate to oppose braking effort thereby to reduce the possibility of a driver overriding anti-skid operation during 'panic' braking. A modified system provides only a single diaphragm actuator for opposing a driver's braking effort under skid conditions.

Vehicle anti-skid braking apparatus

A control coupling in which an enclosure houses first and second sets of mutually interleaved elements in a viscous fluid. The first and second sets of elements are arranged for rotation about a common axis and for driving connection with first and second rotatable members respectively. The quantity of liquid within the enclosure and the construction of the enclosure are such that, at a predetermined working temperature of at least 100.degree. C, the pressure of the liquid in the enclosure rises substantially above ambient. At least one set of the elements is free to move in directions parallel to the common axis of rotation and at least one set of the elements is provided with facings of friction material.

Growing community of inventors

Stratford on Avon, United Kingdom

Anthony P Rolt