The 110 h.p. Clayton Tractor.
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The Most Powerful Chain-track Vehicle of British Design and Manufacture with Original Method of Supporting the Front.
N HIS INTERESTING paper, read before the
Institution of Mechanical Engineers, on " Trac
tion on Bad Roads or Land," Mr. L. A. Legros, M.I.M.E., the well-known automobile engineer, described the various types of chain-track tractors whieh have been developed during the past few years. This development, as we know, has been brought about by the need to reduce the insistent weight to a minimum. That imposed by a horse carried on two feet, as in walking, may exert a pressure on the ground of from 20 to 26 lb. per square inch, whereas the modern chain-track vehicle may only exert a cressure of 4 or 5 lb. per square inch and, thus, will be able to travel over ground or on surfaces the condition of which would preclude the older methods of locomotion.
One of the most interesting vehicles described by Mr. Legros is the 110 h.p. Clayton tractor, made by Messrs. Clayton and Shuttleworth, Ltd. Lincoln, a vehicle which, recently, we were able to inspect in complete detail, although permission to deal in these columns .with its novel features could not, at that time, be obtained.
• This tractor was produced by the company jointly with Mr. W. F. Bainforth, Director of Munitions Mechanical Transport Department, and formerly works manager of Messrs. D. Napier and Son, Ltd. It is the sole representative of high-power chaintrack vehicles designed and made in this country. It derives its power from a 110 h.p. petrol engine, designed by Mr. Rainforth's department and made by the National Gas Engine Co., Ltd., the power being transmitted through a multiple-disc clutch, with alternate steel and Ferodo surfaces, to a gearbox giving three forward speeds and reverse. Thence, the power passes through a worm and worm wheel to driving pinions on the differential shafts and thence to the hind axle, where it is transmitted to the twin sprockets, which engage with the driven pins of the chain tracks.
Steering is effected by means of a pivoted front wheel, assisted by the independent application of brakes to the brake drums, which are carried on the driving pinions.
The most original part of the Clayton tractor is the projecting boom, which carries the front supporting wheel. We show this in a diagram. The boom has twin side members,
braced by a strong "stay plate just behind the wheel: It is hinged at the forward end of the main frame of the vehicle and, at its rear end, is a segmental rack -engaging with a spring pinion, which can be •inaade to rotate by the action of the worm and worm wheel as shown in the illustra• tion, whilst strong springs tend to keep the steering wheel in contact with the ground. The range of movement is 15, degrees each way from normal, and, by means of the elevating gear, the relation of the wheel to the track can be adapted to severe irregularities of the ground, although only approximate adjustment is necessary. One of. our illustrations shows the tractor climbing a 40 per cent.. gradient. The shock that would occur when the bank as climbed and the machine again assumes the level is almost entirely absorbed by the springs controlling the projecting boom. This tractor has not only undergone severe trials in this country, but has served one of our Allies to overcome the difficulty that, without it, might have been insurmountable, of handling heavy guns and great loads over trackless country and surfaces impassable to other forms of vehicular traffic. It has behaved in a most marvellous manner according to all accounts that have reached 'us, proving' to be reliable and amply strong for the work which was demanded of it. It is easy to manage, and, when it careers about the test ground in the manner shown in the upper illustration, is said to give its passengers the next greatest thrill to an aeroplane flight!
A further illustration of the Clayton tractor travelling over rough ground at a steep gradient appears on page 7 of this issue.