A NEW CHASSIS FOR 7-TON LOADS.
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A Popular American Petrol Chassis in an Unusual Size.
CERTAIN makes of American com
mercial vehicle, particulailv some of the heaviest, types, have achieved much popularity amongst,. British users, and although very few American lorries are now to be seen in regular service in this country, considering the number • of war-used vehicles which has been absorbed in the market. One of those which have found favour with a certain section of British owners is the Kelly. Springfield, which is the product of the Kelly-Springfield Truck Co., of Springfield, Ohio. Those users, and others, who keep a watchful eye on developments in the American industry, will probably, therefore, evince a certain interest in the latest production of this well known concern. The new model, although it may not incorporate unusual features in design, is unique in one respect, and that is that. it is designed to carry 5-7-ton leads: Thera are few petrol chassis built with rated load-carrying capacities exceeded 5 tons, and, hitherto, the field of employment for mechanical vehicles beyond this size has remained, almost exdlasively, the property of the steam wagon.
The new chassis has a four-cylinder Kelly engine,_ the bore and stroke of which is 4-Lins. and 6i ins. re'spectively. It is three-point suspended in the frame and includes in its specification the following outstanding details :—Aluminium crankcase, three-hearing crankshaft, carbon-steel camshafts, connecting rods of I-beam construction, self -contained automatic pressure system of lubrication, water circulation by centrifugal pump, Zenith carburetter (gravity -fed from a tank located under the driver's seat), Eisemann high-tension magneto with variable spark advance and impulse
coupling, and a centrifugal type of ' governor of Kelly design. – The engine power is transmitted through a clutch of the single dry-plate type to a fcnrr-speeclaand-reverse gearbox mounted amidships in the cha.ssis frame. The gear ratios are as follow :—First speed 5.33 to 1, second speed 3.08 to 1; third speed 1.57 to 1; fourth speed 1 to 1. From the gearbox the drive is conveyed to a rear axle of the bevel-and pinion type with overhead drive. The service brakes are mounted on the axle shafts, and the emergency brakes, which -are of the internal-expanding type, are. located in the rear wheels.
The steering gear is of the worm-andwheel type, and simple means are provided for adjustment. The steering-gear lever moves in a fore-and-aft direction and is connected with the steering knuckle by a spring-cushioned drag link.
Semi-elliptic springs of ample proportions are fitted, those at the front being 3 ins, wide and 48 ins, long, whilst those behind are 31 ins_ wide and 56 ins. long. The deflection of the front springs per inch is 769 lb.. whilst on the rear springs it takes 2,300 lb. to deflect them an inch. The wheels are of the, metal-disc type, and they aye fitted with solid tyres all round, those at the front being 36 ins. by 6 ins, and' those at the rear 36 ins. by 7 ins. dual.
The weight of the 5-7-ton KellySpringfield chassis is 9,025 lb., the total weight complete with body being 11,525 lb.
The new chassis is being supplied in four different wheelbases, these being 10 ft. 6 ins., 13 ft., 15 ft. and 16 ft. 2 ins. In the case of dump trucks, as that Americans call them, a chassis of 13 ft. wheelbase is specified as standard. Towing hooks are fitted at all corners of the
frame. The Kelly-Springfield chassis has a distinctive appearance, which is largely due to the sloping type of bonnet which is employed.
Whether or not the new chassis will make its appearance on the British market it is difficult to say, but since it possesses a load-carrying cataaeity beyond the range of the great majority of petrol chassis produced in this country it is a possibility which should not receive instant dismissal at the hands of British makers and users.