Special Atkinson Tractive - Unit at Show A MONG the Atkinson vehicles
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to be exhibited at the Commercial Motor Show is a special semi-bonneted fourwheel tractive unit for B.R.S. (Pickfords), Ltd. Designed for a gross train weight of 32 tons, it has a wheelbase of 10 ft 0.375 in. and is one of seven on order.
The power unit is the Gardner 6LX unit and the drive is transmitted through a 16-in.-dia. clutch to a six-speed constantmesh gearbox mounted as a unit with the engine. The gearbox ratios are 9.23, 5.46, 3.73, 2.39, 1.592 and 1 to 1 forward and 8.04 to I reverse.
The rear axle is a double-reduction unit with spiral bevel primary gearing and epicyclic huh reduction and has an overall ratio of 6.56 to 1. An alternative hypoid-hub-reduction axle enables the tractive unit to be uprated to a gross train weight of 50 tons.
The air-pressure braking system operates through diaphragm units, the drum diameter and shoe width being 16 in. and 5 in. respectively on the front axle and 16.5 in. and 7 in. at the rear.
The frame side-members are 8.25 in. deep, have 3-in.-wide flanges and are 0.375 in. thick. High-tensile bolts are used for the frame assembly.
Other features include Mules camand-double-roller steering gear, 9.00-20 (14-ply) tyres (twins at the i.ear), Morrisblock-type radiator. 54-gal. fuel tank and Scammell heavy-duty fifth-wheel. -..The new Pickfords tractive unit will be one of seven vehicles on the Atkinson stand. Two of these are 1746 24-ton gross tractive units, of which one is a special lightweight 9-ft.-wheelbase version for J. and A. Smith (Maddiston), Ltd. Weighing 4 tons 5 cwt. complete with fifth wheel, unladen, it incorporates a lighter frame and wheels, non-grooved springs, a spiral-bevel hub-reduction rear axle (which accounts for 2 cwt. of the weightsaving), a Morris-block radiator and a six-speed gearbox. The other T746 is a standard 8-ft. 9-in.-.whee1base model.: None of the recently introduced Weightmaster lightweight models will be on the Atkinson stand, as examples are being displayed on the stands of the Yorkshire Engineering and Welding Co. (Bradford), Ltd., and W. P. Butterfield (Engineers), Ltd., as well as in the demonstration park.
The four eight-wheelers on th..: Atkinson stand will all be examples of the standard 1786 series, although one of them, for Bulwark Transport, Ltd., is a lightweight version of this model. It has a glass-fibre-panelled cab with light alloy framework. The frame side-members are 0.3125 in. thick, instead of 0.375 in.. and lightweight front springs are fitted.