An American Agrimotor for £160.
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By Henry Sturmey,
A couple of years since I described in THE COMMERCIAL MOTOR an American farm tractor, of very ingenious design intended to do all the haulage work of the farm. But the price—$2500—waS against it, and I am not surprised to have heard no more about it. Inventors in the States have, however, been pursuing the question still further and have now pro-, duced a machine which is remarkable for its originality of design and all-round usefulness, as well as for its price, which is at factory but 13765 (Z1.58 19s. 2d. or, say £160 in round figures).
It is not a light construction with little power, able -only with difficulty to plough a single furrow, but, so far as ploughing is concerned, it is built to do the work of a twelve-horse team and to haul a four-furrow plough, and, in addition to being able, of course, to draw any form of agricultural implement or wagon usually hauled by horses, itis provided with belt pulley and can be used as a stationary engine for driving, threshing and winnowing maObines, chaff cutting and all other such processes employed on and about a farm.
• The design is most ingenious and is shown very clearly in the annexed " bird's-eye view" photograph, from which it will be seen that conventional motorcar design is entirely abandoned. The engine is a four-cylinder horizontal one with opposed cylinders, and detachable cylinder heads ; it has 5 in. bore by 5 in. stroke, and gives 30 b.h.o. at 850 revs. It is not an adapted lorry engine, but one Specially built for the sob. It has 24 in. by 5 in. and 6 in. main bearings and 31in. by 3 in. connecting rod bearings, and is fitted with magneto ignition,
This engine is set with the axis of its crankshaft across the machine, being mounted on a horizontal framework with channel-steel and flat-steel bracing. Magneto and circulating pumps are carried on the outside, and so are easily get-at-able. The carburetter—a ;Kingston—is set on the top of the engine between the cylinder blocks, and a governor, of the throttling type, running in oil, is provided. The inside end of the crankshaft carries clutch and flywheel in unit construction, which connect up with a, very simple two-speed-andreverse gear carried on the opposite side of the frame.
This gear is of the sliding order, but has only one spider for both intermediate gearwheels, both. high and low-speed gears being cut out of steel rings and bolted to the spider, so that in case of damage only the gear ring neecrhereplaced, both being easily and quickly detachable. There are
only seven gearwheels in all, including the master gear and pinion to be presently described ; all the gears—except the latte.• which are self-lubricating—run in a continuous bath of oil.
The machine is a three-wheeler, a single driving wheel only being used. This is of double the width on the face that two wheels would collectively be—viz., 30 ins.—thus giving large ground surface of support for working over soft ground, and the wheel face is provided with removable grip studs arranged in diagonal lines over its surface. This arrangement, of course, eliminates the need for a differential and gives a three-point ground support for the whole machine. It also enables the driving wheel to be rigidly mounted in tho frame, on short large-diameter shafts supported at both ends. -This„driving. wheel is 5 ft. in diameter and Is furnished on the inside -of its broad rim at one end with an internally-cut gear ring, or "master gear" as the makers term it, of generous proportions. This master gear is located contiguous to the right-hand side of the frame and is driven by a.pinion with roller teeth running in oil in connection with the driven shaft of the gearbox ; it is held up to its work by a long bearing coming right up to the inside 'edge of . the frame.
The "master gear" is therefore lubricated continuously by the master pinion," and so it will be seen that lubrication throughout is very carefully schemed.
The gears are enclosed in an oiltight, dust-proof ease, and the driving wheel itself is encased. A 25-gallon fuel tank is carried on the flat steel platform of the frame on the engine side, and a pressed steel seat, spring-supported, on the other, this being placed on the near rear corner of the frame, in such a position that the operator has a clear vision of the -furrow ahead and is at the same time in the best position to observe the implements he is hauling. Steering is accomplished by means of a wheel and long steering post in front of the driver, onerating the two spring-supported front wheels by Ackermann joints, and one hand lever and one pedal suffice for the control.
At the centre of the frame—at the back rear member of the frame ferming the Arawbar—is a hook-up clamp, by which the trailed implement is attached. The brake is a drum mounted on the engine shaft and operating through the gear, and, as the reduction is so great, the power over the manhine should be ample. Cooling water for the engine is carried in a 35-gallon tank over the front axle.
The starting handle is applied to an extension of the engine shaft beyond the gearbox, and upon this extension a broad belt pulley is mounted, so that when required to be used as a stationary engine, it is only necessary to belt up to the machinery required to be driven.
In use it is claimed that the tractor will displace a team of 12 horses, and that, under fair aver: age conditions, it will handle four 14-in, stubble ploughs. The two: speed ratios provided give travelling speeds of one and four miles per hour respectively, and when ploughing, after the first traverse of the ground has been made, the machine is practically self-steering; as the near wheel runs in the track made by the off wheel on the first trip, and steering thus becomes practically automatic. The wheelbase overall is 7 ft., length overall 12 ft. 2 ins., width of tread 7 ft. 10 ins., and the gross weight 4500 lb.—say two tons. It is generally claimed for it that it will do all the work of the farm, that it costs but one-third of what the horses it replaces cost to buy, and that it works at one-halF thencost.
The machine is very simple in design and appears to be strongly made. At its price there should certainly be a wide field of usefulness open to it in the service of the agriculturist.