A New Double-decker
Page 49
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NO make of chassis has achieved a more enviable reputation amongst passenger-vehicle operators than the T.S.M., formerly known as the Tilling. Stevens. An important newcomer from Victoria Works, Maidstone, which is the manufacturing headquarters of T.S. Motors, Ltd., consists of a special chassis for double-deck buses.
It has an unusually deep frame, with no fewer than seven cross-members behind the engine, excluding those for carrying propeller-shaft bridles, etc. The rearward extension is, of course, downwardly cranked to carry the platform. High-tensile steel bolts are used throughout the construction, no rivets being employed. The engine is carried on a sub-frame and the separately mounted gearbox is slung from two of the cross-members.
In this frame the engine and transmission are offset to the left, the drive line being inclined, but care has been taken to cause the minimum amount of angularity to be dealt with by the universal joints.
The engine develops 50-55 b.h.p. at 1,000 r.p.m. and 108-109.5 b.h.p. at 2,500 r.p.m. A special point has been made of obtaining marked fuel economy, despite the high output. The cylinders
have a bore of 4 ius, and a stroke of 5i ins. They are cast rnonobloc and have two detachable heads, each covering three bores. The crankshaft runs in four bearings and drives the camshaft by a helical-spur gear. The valves are situated side by side and the magneto and water pump are mounted transversely at the rear.
Four forward speeds are provided in the gearbox and the control lever is mounted in a recess in the engine casing to the near side of the driver. From it three shafts run to the gearbox, the entire top of which may be removed to facilitate inspection.
The clutch is of the single-plate type and is equipped with a stop. Between the clutch and the gearbox flexible disc joints are used, whilst the final shaft has mechanical joints, one of which operates on splines to permit plunging.
All of the springs are of the semielliptic pattern and the use of centre bolts has been obviated. The brake pedal operates through a Dewandre servo, mounted outside the frame, and thence through a master adjuster and relay levers to drums in all four wheels. The hand lever operates separate shoes in the rear-wheel drums.
Final drive is by underslung worm, and the shafts are fully floating. The front axle has renewable phosphorbronze bushes for the swivel pins, and the load is taken on taper-roller thrust bearings. Marks steering is employed and 86-in. by 8-in. tyres are provided, those on the rear wheels being dual.
The leading dimensions are as follow ;—Wheelbase, 16 ft. 1 in. ; frame height (laden), 2 ft.; overall length, 26 ft. ; overall width, 7 ft. 51 ins.; dashboard to end of frame, 20 ft. 81 ins. ; width of frame at rear, 3 ft. 114 ins.
This chassis is constructed to carry a 52-passenger body which will weigh 21. tons: Several of these models have already been purchased by important operato es.