From basic workhorse to sophisticated steed
By Mike Williams
AN American named John Charter was probably the first person to build a tractor.
That was in 1889, and he used it instead of a steam engine to power a threshing machine.
The Charter, and most of the other tractors which followed over the next 10 years, had just the basic essentials including an engine, a simple transmission, four wheels and a pulley to power a belt drive. Some even lacked a seat for the driver. All the other features which make modern tractors versatile, productive, safer and more comfortable for the operator were developed during the next 100 years.
Many of the companies and individuals who made the important contributions to tractor design are easily identified, but the origin of some features is more difficult to trace. What is certain is that some of the "latest" developments, like front axle suspension, are not as new as manufacturers may claim.
1 Diesel engines The first production tractor powered by a diesel engine was made in Germany by the Benz company in 1922. It was a twin-cylinder diesel, and the tractor was called the Benz-Sendling. Early diesel engines were often hard to start and ran unevenly, and the first of the modern, smooth-running, easy-starting diesels were developed in Britain by Ford and Perkins during the 1940s.
2 Turbocharger Turbocharging is popular because it boosts engine efficiency, reducing fuel consumption and cleaning the exhaust emissions, but when it first appeared on American tractors in the 1950s it was just another way to squeeze more power from a diesel engine. Caterpillar was the first manufacturer to use turbo engines regularly, starting with the D9, and by 1959 the D8 engine was also turbocharged.
3 High speed transmission A souped-up version of the Allis-Chalmers Model U set a world speed record for tractors at 67mph in 1933, but the first production tractor with a high-speed transmission was the Minneapolis-Moline UDLX, which was available from 1938. It had a five-speed gearbox and a foot throttle, and the top speed on the road was 40mph.
4 Front axle suspension They are all the rage now, but suspension systems for the front axle are not new. The first experimental tractor from Henry Fords design team in 1907 included a front axle with transverse leaf springs, although the idea was not included when the first Fordson tractors arrived in 1917.
5 Four-wheel drive Putting the power through the front and rear wheels is older than the tractor, first appearing on American steam traction engines in the 1880s. The Heer Engine Co of Portsmouth, Ohio, was probably the first tractor company with 4WD, providing equal-size front and rear wheels and a chain and sprocket drive to both axles on their 25hp model produced in 1910.
6 Rubber Tyres Several companies experimented with solid rubber and high pressure truck tyres before Allis-Chalmers made a breakthrough in 1932 when they tried a pair of aircraft tyres on the drive wheels of a Model U tractor. These tyres could be used at 15 psi inflation pressure – much less than normal – allowing better traction in the field and faster speeds on the road. Tyre manufacturers were quick to produce special designs to exploit the new market.
7 Power take-off John Scott retired from his post as Professor of Agriculture at what is now the Royal Agricultural College, Cirencester to concentrate on ideas for tractor development. These included what was probably the first tractor with a pto, which he took to the 1904 Royal Show. The pto was gear driven and was at the front of the tractor for powering equipment such as a mower or a binder.
8 Powered implement lift Using muscle power to lift an implement for headland turns was hard work, and by 1918 engine powered mechanisms were available to ease the strain. These were awkward to use, but Harry Ferguson found the answer with hydraulic power, his three-point linkage. The first production tractor with the new system was the Ferguson Model A, built in the David Brown factory from 1936.
9 Cab Some of the earliest tractors had a simple canopy to keep off the worst of the weather, but the first cab designed for the safety and comfort of the driver arrived in 1938 on the Minneapolis-Moline UDLX tractor. It was made of steel to survive an impact, with safety glass in the windows, and the specification was at least 30 years ahead of its time with two padded seats, a heater, radio, cigar lighter and even an ashtray.
10 Electric starting Hand cranking an engine into life was never a popular job, and American tractor companies offered various alternatives including spring-powered starters and, in 1908, a compressed-air starter. The first company to use electric starting was probably the Moline Plow Co. which added a battery plus an electric starter motor and road lights to their Model D tractor in 1918. *