A TWO-TON VULCAN WITH NEW FEATURES.
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Improvements to An Enlarged Engine.— Overhead Worm Drive.—Choice of Axle Ratios.— Special Attention to Brakes.
THE •Vulcan Motor and Engineering Co. (1906), .1A4., are introducing a new twa-ten'chassis --which is a development of their already well-known 30-cwt. vehicle.
In general outline the engine is not much changed, although being five millimetres larger in the bore than the old one, it is now rated at 22.4 h.p. The principal improvement is the largediameter hollow crankshaft, through which oil is forced from the 1i-gallon sump to the big-end and main bearings by a gear pump driven from the rear end -cif the camshaft by a mitre wheel. At the front end of the crankshaft a Hoffman thrust washer is fitted.
The enclosed side-by-side valves located on the near side of the engine are operated by adjustable tappets. The carburetter is situated on the other side of the cylinder block, the inlet, and exhaust manifolds being cast in one piece on the near side to assist rapid warming up of the mixture from cold.
The engine, which is held in the frame at four points, is provided with a Ferodo cone clutch with adjustable springs. The clutch shaft, equipped with a flexible disc universal joint, transmits the power th the four-speed central-change ,gearbox, where either of the, following sets of gears can be utilized by changing the axle ratios : 6.2, 9.65, 15.95, and 24.8 to 1 forward and 33.06 to 1 reverse, or 7.25, 11.3, 18.7 and 29 to 1 forward and 38.7 to 1 reverse. The second aet is recommended for Ireland or the Colonies and the former for use in England.
The universal joint behind the box is of the compound type of cross-pin pattern, whilst the drive and final reduction• are effected by a tubular shaft of great strength and an overhead worm.
The internal-expanding brakes on the bark axle measure some 18 ins, in diameter and are controlled by hand, the foot. brake being located on a drum im
mediately behind the gearbox. The rear axle is of the fully floating type, the worm wheel and differential being.
carried on heavy duty ball bearings, whilst the road wheels are carried on plain floating bearings.
Steel wheels fitted with 860 mm. by 100 mm. solid tyres, the rear pair being twins, are standardized, although arrangements may be made to fit super-cushion or pneumatics as an extra. In the case
.of super-cushion tyres 100 mm. for 720 mm. front and 180 mm. for 720 mm. back are recommended. The pneumatic sizes are 880 mm. by 120 rum, single in front and twinsbehind, or 895 mm. by 135 mm. singles in front and twins behind. In the case of the giant pneu. matie 36 ins. by 6 ins, is the size fitted in front and 40 ins. by 8 ins, at the rear. Electric lighting is another item which is not, included in the price of £575.
It will be seen from the illustration that, in order to economize space, the large ,specially designed radiator is carried well forward on the dumb-irons. Consequently it has been possible to provide 'an 11-ft. platform on an 11-ft wheelbase without excessive ,overhang, 'For buses and chars-k-banes the wheelbase is lengthened one foot from the standard, whilst a 10-ft. wheelbase is Specially listed for short vehicles, and -.should prove particularly suitable for carrying bodies intended for municipal work in narrow thoroughfares.
The suspension, both front and rear, relies on semi-elliptic springs, in both cases clipped to the top side of their respe tive axles: The petrol tank contain g .12 gallons of fuel and is located in the lash, thereby enabling the Zenithcarburetter to be fed by gravity. The frame is of very sturdy construction, the straight side members being cross-braced by five members, from two of 'which the 'gearbox is hung.
As an example • of a complete vehicle utilizing the new chassis, one illustration:shows a small bus capable of carrying 20 passengers. This body was made at tha'Vulean works a point of interest being the side-door control, which can be operated by the driver and simultaneously folds -up the entrance steps. 'The driver has a door on the off side, and also a sliding side.window to facilitate
.hand-signalling. In this case a side change lever is provided as an alternative to the standard central change.
The interior bodywork nicely finished and all seats are carefully planned to ecreforn to the curve of the back. A central gangway, electric light and wide window spaces are other features of interest.