THE SERVO SYSTEM

Sun (Auckland), Volume II, Issue 337, 24 April 1928, Page 6

THE SERVO SYSTEM

EASING WORK OF STEERING

The latest invention, designed to reduce the fatigue of long-distance motoring, is a device which practically takes the labour of steering out of the hands of the driver. The servo motor which has been applied so successfully to brakes has now been adapted in America to operate the steering gear. The invention is being tested by a well-known maker of eight-cylinder cars, but as yet there is no assurance that it will become a standard fitting. The ordinary wheel is used for servo steering. The lightest touch on the wheel brings the servo motor into operation, and the pull is provided. The feel of the steering soon becomes familiar, and in general use the servo motor takes nine-tenths of the labour of steering the car. For some time past the question of reducing the labour of steering has occupied a great deal of attention, a considerable increase in the leverage with which the driver is provided being found absolutely essential to combat the drag produced by low-pressure tyres of large section. Up to now the result has been an all-round lowering of steering gearbox

ratios, so that to execute a given manoeuvre the steering wheel of a modern car must be moved through a much bigger angle than was once necessary. The device under test is compactly arranged in a small cylindrical casing, mounted on the steering column just below the footboards, and consists essentially of two brake drums which are slowly driven in opposite directions by means of gearing and a universally joined shaft, from some convenient rotating part of the engine. Each drum contains a springy brake band, one end of each band being securer to a radial arm, which is in turn keyed to the shaft carrying the worm of the usual steering gearbox mechanism. It is stated that in the experimental device the mechanism is arranged to give a torque amplification of ten to one, which means that without any alteration to the steering gearbox ratio the use of the servo device would reduce the steering effort to one-tentli of its normal value. The effect of so enormous a reduction in labour when parking a heavy car or manoeuvring in a confined space will at once be realised, another point being that when the engine is ticking over, and the car stationary, it is child’s play to move the wheels through any desired angle by means of the steering wheel.

CHANGING COSTS llow the costs of owning and running a car are changing their ratios was recently explained In a lecture b' Mr. W. M. Webster, ••ommissioner the Auto Equipment Association of U.S.A. “In 1915.** he said, "a motorist sj*27 cents of every dollar on service, bu: now 57 cents of every car dollar it spent in that way. “During 1928,” he forecast, “SO cents of every dollar will go to service *rthe remaining 40 cents for actual car sales.” He estimated that the world registration of motor vehicles would toy 30,000,000 by December. The membership of the A.A.A. is bp* over the 7,000 mark. * • * Some surprise was expressed by motorists at uhura when they were advised that the benefits of the AA A were available to them. There wat a general impression that this distnt: was within the jurisdiction of th* Taranaki Association. When the position was indicated, several Ohun motorists joined the A.A.A.