New Features in a 12-ton Machinery Carrier
Page 70
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DESIGNED to operate with either Lithe old chain-drive-type of tractive unit, or the latest models with pneumatic tyres, a new type of droppedframe machinery-carrying semi-trailer has been introduced by Scammell Lorries, Ltd., 52-54, High Holborn, London, W.C.1. The example shown in the accompanying illustrations has just been supplied to the Red House Garage Co., Ltd., Coventry. It is seen carrying a boiler, weighing about 11) tons, which was transported from Coventry to Bridgwater.
Built for minimum weight (the complete semi-trailer weighs 3 tons oi cwt.), the combined body and frame is of welded-steel construction, having a floor plate 7/32-in. thick. This is freely reinforced by angle pieces and crass-members. Box-section girders, stiffened by diaphragm plates, form the main longitudinal members, and these are extended at their ends to carry trunnions upon which oscillate the two detachable rear axles. Holes are punched in suitable positions to reduce weight. A main platform area measuring 12 ft. 7 ins. by 7 ft. 5 ins, is afforded, whilst the bow front provides a platform 7 ft. long by 7 ft. •5 ins. wide.
Under this is the top half of the turntable, which consists of a one-piece pressing bolted to timber-filled transverse cross-members. It carries the Scammell patented king-pin-actuated brake gear. Upon this platform is mounted a triple-purchase 4-ton winch.
Of special interest is the wheel and
axle gear. Arranged in line, the four wheels are shod with 33 by 9 pneumatics, one wheel being mounted at each end of the two axles, which, as mentioned before, oscillate on extensions on the side members and can thus follow road-surface contours. Each trunnion incorporates a rubber compression-disc springing device.
Provision is made for the easy removal of the axles, which can be detached together or separately. The operatim takes about five minutes, and is accomplished with the aid of combined screw-and-jack lowering gear.
Girling brakes are used, the shoes being accommodated in 16-in. drums, 3-ins. wide. They are applied by manual or servo gear, inthe latter case the cylinder being mounted on the motive unit.