A Sphere in Which The Specialized Semi-trailer Excels
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Dyson Detachable-axle Lowloading 50-60-tonner for Use with Interchangeable Tractive Units
nNE of the foremost among hauliers
specializing in the transport of really heavy loads, Road Engines and Kerr (Haulage), Ltd., 4, Marine Street, Glasgow, for the past few years has been modernizing its fleet, and has devoted particular care to the selection of trailing equipment and tractive units of types that afford wide versatility of function. A recent acquisition is the, semitrailer seen coupled to a Foden in the
accompanying picture. It is a product of R. A. Dyson and Co., Ltd., and is designed to carry exceptional
loads. When used with the tractive unit illustrated, 25-89 tons can be dealt with, whilst loads up to 60 tons in weight can be transported if it be coupled to a specially constructed Scammell, operated by the company.
Naturally, in the latter case, the speed at which the outfit can travel is considerably lower, than it is with half the pay-load, and the two tractive units are used because their respective performance .characteristics ate in accordance with both conditions. Thus efficiency is promoted.
Furthermore, it frequently happens that the semi-trailer has to be run light after delivery of a big load or to a works for loading, and it may be economic and/or convenient to use a different tractive unit for this operation From that employed for the actual transporting of the articles. • Indeed, an outstanding feature of the Road Engines and Kerr service is that the company will run the trailing par tion of the outfit into a works so that the machine to he carried can be erected thereon, and, similarly, will leave the unit at the point of delivery if it happens that the work of lifting off the load cannot be immediately undertaken. Then, later, a light tractive unit goes out to bring back the empty semi-trailer which it can tow at relatively high speed.
Whilst the length of the low platform, measured from the step to a point in front of the rear wheels, is 18 ft., the overall length of the Dyson unit is 30 ft. 8 ins., and to enable advantage to be taken of the total space available a demountable bolster is provided at the back. Thus, very long loads such as gun barrels, Lancashire boilers,. etc.: can he accommodated. The loading height of the main platform is only 1 ft. 6 ins. and there is about 6ins, clearance under the lowest part. There are four rear wheels arranged in line, each pair on a detach able rocking axle. Giving big load capacity -combined with a minimum overall wheel diameter, Dunlop tyres of a special design are used, each wheel carrying twins. They are solid and are unusually thin (considered radially) in relation to their width measured across the tread,
Secured by bolts hinged at the lower ends„ the axles pass over the framegirders which are tapered rearwards from the hack of the platform to a short parallel section at the extreme ends.
In view of the big loads for which it was designed, the frame is extremely strongly built, whilst for stability during side loading jacking platforms are provided at each corner. 'Braking is effected by Girling equipment, operation 'being by pull rods and bell cranks from a central push-rod in the turntable king pin, or by a band wheel on the near-side cheek plate.
Much ingenuity is to be found in the constructional details of the trailer, which is a welded and riveted structure incorporating two main longitudinal members each formed of a pair of girders arranged back to back, spaced 61 ins, apart and heavily plated.
Channels, fitted into these, plated above and below and extended at the sides form the cross-members and the platform width is 8 ft. 6 ins.