A New Fourwheel-drive Tractor
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OR work over trieky surfaca, four wheel-drive lorries have proved their worth. In the case of tractor operation the risk of encountering difficult going is very much greater, therefore the employment of a drive to all wheels offers many advantages. It is chiefly on this account that the new MasseyHarris general-purpose tractor is" such a noteworthy newcomer. It is, sold in thiS" country by Massey-Harris, Ltd., 53-55, Bunhill Row, London, E.C.1.
Behind the engine is a central transmission housing to which are anchored the casings for the drive to the_ front wheels Half-shafts convey the power tothe front wheels, which, of course, control the steering. Braking also occurs through the front wheels, the drums being mounted on the differential. The front axle, as it may be termed, is rigidly connected to the main• frame and, when passing over uneven surfaces,the angle of the front axle is that of the rest of the tractor, with the exception of the rear axle; the last named is mounted so that it can pivot, thus permitting a wide range of axle-height variations, but enabling the drive to be continuous through all four wheels. The system of taking the power to almost the highest point of each wheel gives a clearance of 130 less than 12 ft. 6 ins. wider the axles.
Engine and transmission assemblies form the frame. The power unit has four cylinders in line, and the bore and stroke are 4 ins. and 4i ins. respectively. The valves are. located on one side and the crankshaft runs in three 2-in. bearings. The lubrication system is a combination of pressure feed and „splash.,. Petrol, is employed as the fuel, and the engine runs up to 1,200. r.p.m. There is an impulse 'starter On the magneto, and the air cleaner is of the oil-wetted type. A centrifugal governor is provided. and cooling isiaided by e.. centrifugal pump forcing water through the tubular radiator, through, which the air stream is induced by an 18-in. fan.
A three-plate clutch takes the drive to the gearbox, which gives tractor speeds of 2.2 m.p.h., 3.2 m.p.h. and 4 m.p.h, and 2 m.p.h. in reverse.
All four wheels are of 3 ft. 2 ins. diameter and of 8 ins. width, -whilst the tractor can be obtained in four track sizes, viz., 5 ft., 5 ft. 6 ins., 6 ft.
4 ins., or 4 ft. for orchard work.
The wheelbase is 4 ft. 3 ins., and the turning radius—taken to.,, the inner wheel-circle--can be as small as 3 ft. This machine weighs 1 ton 14i cwt., and is priced at 1270, delivered to the farm and started. If required, electric lighting, starting and a power take-off can be supplied, also extension controls to enable the machine to be driven from the seat of the drawn implement. A belt pulley is a standard fitment.
A noteworthy point is that the clutch is controlled by a hand lever, so situated that the driver, standing behind the machine, can regulate its . backward motion while holding, the drawbar of the implement to which the tractor is to be coupled.