New Big 4 X 4 Snow Plough
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DESIGNED for use in conjunction with proprietary rotary snow-plough units, a 4 x 4 chassis has been introduced by Douglas Equipment, Ltd., Cheltenham The use of two reduction gearboxes in addition to the standard gearbox gives the vehicle a snow-clearing operating speed of 300 yd. per hour. The normal road speed is 30 m.p.h.
The snow-plough carrier is based on a 10-ft. 6-in, wheelbase chassis and it is powered by a Commer six-cylindered petrol engine developing 85 b.h.p. at 3,100 r.p.m. and 202 lb.-ft. torque at 1,200 r.p.m. This drives through an 11-in.diameter single-dry-plate clutch to a fourspeed synchromesh gearbox, behind which is a special crawler gearbox connected through a Layrub-jointed shaft.
The crawler box has ratios of 3.89 and 1 to L The low ratio is intended for snow clearing only. The drive then passes through another Layrub joint to a transfer box which has the same ratios as the crawler box, but also gives front-wheel drive when required. The lowest available bottom-gear overall ratio with the standard 6-to-1 axles is 654 to 1.
Spiral-bevel final drives are employed in the front and rear axles, and semi-elliptic springs and telescopic shock absorbers are fitted all round, with rubber buffers between the axles and chassis frame. The worm-and-sector steering has a hydraulic servo as standard, and Dunlop Trakgrip 9.00-20-in. tyres are mounted on all wheels. The hydraulic brakes have a vacuum servo, and the mechanical hand brake is effective on both axles.
A trunnion mounting is provided at the front of the chassis for the snow plough. which is lowered from its normal c10 travelling position by twin hydraulic rams. The jockey, wheels normally necessary with snow ploughs to support the weight of the equipment when travelling are not required in the Douglas.
The plough is driven by a 130 b.h.p. petrol engine at the rear of the chassis, the drive passing through a conventional clutch and gearbox to a special reduction gearbox which relays the transmission to the side of the chassis. An oil engine is offered as an alternative.
The -standard forward-control cab has seats for a driver and passenger, but an extra-large cab can be provided for additional crew. The body enclosing the plough engine includes locker space for manual equipment.