Novel Adaptation of Multiwheeler System
Page 37
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rACED with the problem of selecting a tractor to tow a I' trailer having a gross weight of 10 tons, Messrs. R. J. Weeks, Waterdeia Road, London, E.15, have embarked upon the experimental course of equipping a standard Bedford short-wheelbase 3-ton chassis with the towing apparatus of Multiwheeler (Commercial Vehicles), Ltd., 3, Grosvenor Gardens, London, S.W.1, and using it in conjunction with a four-wheeled trailer made by the lastnamed concern.
The outstanding feature of the Multiwheeler system is that mechanism is incorporated Which automatically superimposes weight on the rear of the tractive unit in direct proportion to the drawbar pull exerted.. Thus, the adhesion between the driving wheels and the road surface is greater when the tractive load is heavier, whilst under easier conditions the tractive unit runs comparatively light, nearly the whole of the weight of the trailer -being carried
on its• own four wheels. . • • Ihe mechanism of the device has been described in this paper on several occasions in the past, the most recent being in our issue dated October 4, 1935.
The special nterest of the case under consideration lies in the fact that the machineillustrated is, we understand, the -first lorry chassis of a popular standard model:to have been equipped with the Multiwheeler towing gear. This type of outfit was chosen in preference to a tractor-trailcr unit or an articulated vehicle of the usual sort, because of the advantages named above, which result in the elimination of wheel-spin when hill-climbing, accelerating, etc., but minimize the loading of the driving axle.
The vehicle will he used, we are informed, for timber haulage, with a long flat-platform trailer, and is to be operated in fairly level country. It is licensed as an articulated vehicle.
In equipping the Bedford tractive unit with the Multiwheeler towing pillar, screw gear, etc., no difficulty was experienced. The platform, which forms a ramp to lift the drawbar. when coupling, is mounted on supports shaped to fit the frame longitudinals where they are kicked up over the axle. In order to prevent excessive weight transference from the front axle, when lull-climbing, the drawbar pillar has been set 6 ins, in front of the axle.
There is a space in front of the pillar triangular tie, in which a 2-ft. 4-in, body can be accommodated if required.
Dewandre vacuum brakes are incorporated in the trailer and coupled to the tractive unit by a flexible connection. These are Operated by a separate Dewandre vacuum valve, discernible in the accompanying detail picture. An ex,tra hand lever, Mounted alongside the standard brake lever,
.controls the vatuurn Valve. Its traiiei is limited by a positive stop, to protect the valve from damage.