Chapter 11
The De Dion Voiturette
This little car was brought out about the end of 1899 to meet the demands for a cheap yet fast car. Its peculiarity consists in the adoption of a live axle which bears no part of the weight of the vehicle. The driving wheels revolve on tubular studs fixed to the framing; a curved bent tube braces the sides and studs together, really acting as the carrier axle. The diagrams (not to scale) figs. 35 and 36 show the arrangement.
A is the lower part of the carriage frame, which carries the engine. Attached to this is a gear case B, in which is a large spur wheel driven by a pinion, not shown. The large spur wheel in B carries at each end of its shaft two couplings, from which universal shafts D D proceed right and left to couplings attached to the wheel. C is the bent axle carrying the weight of the car. As a universal shaft can work at a very considerable angle, the up and down motion of the carriage on its springs in no way interferes with the working of the transmission gear. This method was adopted by MM. de Dion and Bouton as early as 1894 in their steam cars. Of course, it entirely obviates the use of chains, and springs of a very considerable elasticity can be used. The engine is vertical, water-cooled, and driven into a gear box containing two speeds, which is described below. An extension of the shaft drives a small centrifugal pump, which circulates the cooling water. Six radiating tubes, each eighteen inches long, and covered with grills, are arranged on the forepart of the car. The steering is by a bent handle, and below this are the brake, change speed lever, and an arrangement for throttling the exhaust; this checks the engine and reduces the noise of the exhaust.
The engine can be started from the seat by turning a crank handle on the driver’s right; a chain couples this with the engineshaft. To take up slack in this chain the handle bearings are mounted in an eccentric, which on being moved round tightens the chain. The change speed gear is shown in figs. 37 and 38, the left-hand engraving being a section in plan; that on the right a transverse section through gear box.
The engine drives the shaft M by the coupling B. On this shaft are keyed two pinions P P; these gear with two wheels on the countershaft, being always in gear. The difference in diameter of these two sets of gear wheels affords the two speeds. Attached to these wheels are two plain rings or friction clutches; in these, and attached to the shaft, are the expanding segments D, which, when forced away from the shaft, press on the inner part of the rings and are then driven by friction. These are forced by the right and left-hand screws, which have in the centre of their length a worm pinion gearing into the threads on the spindle C. This, when moved laterally, tightens one clutch and loosens the other. This gear has the advantage of being quiet in action. Mr. Mecredy, of Dublin, has written a very readable and useful pamphlet on the De Dion voiturette. It can be obtained from the author, Dame Court, Dublin.
The Darracq car is, in external appearance, very similar to the Motor Manufacturing Co.’s Miniature Panhard, but it has a fore and aft shaft working on to the bevel wheel on the main live axle, as in the Argyll. The Renault and the Gladiator cars have also the same arrangement.
It would be impossible to describe all the light cars on the market. The Wolseley light car has a very good repute, and will doubtless before long prove a popular car. There are many makers who can hardly be called car builders, as they simply purchase the engine and certain parts and put them together.
The only heavy oil cars that the writer is acquainted with are the Roots, made by Messrs. Roots and Venables, of Westminster Bridge Road, and the Koch, a French car. This latter has a balanced engine, two pistons working in opposite directions at opposite ends of the cylinder, the explosion taking place between the pistons. As the pistons work in opposite directions, the engine is well balanced, and the vibration so objectionable in the ordinary single engine is obviated. Probably these balanced engines will be largely used in the future. Of course, there are more working parts, but as the stroke of piston must be comparatively short unless an extremely long cylinder be used, they can be safely run at high speed, and considerable power developed. Two types of balanced engines are shown in figs. 38a and 38b. The pistons and cranks balance one another; that shown in fig.38a was introduced by Linford in his early gas engine, about 1878.
