Page:Motors and motor-driving (1902).djvu/230

198 together the whole contrivance is held rigid and revolves as a solid wheel. By connecting any one member of a gear of this character with the engine shafting, and another with the wheels, and locking the third to the frame of the car, a great variety of adaptations can be made to meet special needs, this arrangement having the advantage of neatness and compactness, and having all the gear wheels in constant engagement with each other all the time.

A gear of this character is used upon the Duryea, which has probably the simplest transmission system of any, and is quoted as the most striking example of direct chain transmission. In this the Crypto is carried on the engine-shaft, and for ordinary use the inner and outer members are locked together by a friction clutch and catch bolts, the whole revolving solid, whilst a self-lubricating silent block chain carries the power from a sprocket on the gear direct to the differential on the axle of the driving wheels; thus under all ordinary running conditions there is only the friction of the direct chain drive from engine to wheels. All intermediate speeds are obtained by varying the speed rate of the engine, which in this case possesses great flexibility and power, and will take the car up a 1 in 8 grade without change of gear. When steeper gradients than this have to be tackled a brake holds the outer wheel of the Crypto, which is driven by the inner wheel and a 75 per cent, speed reduction of the sprocket in connection with the pinion-ring obtained, whilst for reversing a band brake is in turn applied to the pinion-ring, which is thus held to the frame and the action reversed. The general arrangement of the gear on this car is shown in fig. 15, where represents the engine,  the fly-wheel,  the Crypto tucked inside it,  the steering-handle, working, by means of the lever, the clutches  is the outer bearing of the gearing,  the driving sprocket,  the chain, and  the differential on the driving axle. The gear changes are made by raising or depressing the handle grip on the steering lever, and the reverse brake applied by the depression of a lever by the heel.