Definition:
A tractor is a vehicle specifically designed to deliver a high tractive effort (or torque) at slow speeds, for the purposes of hauling a trailer or machinery used in agriculture or construction. Most commonly, the term is used to describe a farm vehicle that provides the power and traction to mechanize agricultural tasks, especially (and originally) tillage but nowadays a great variety of tasks. Agricultural implements may be towed behind or mounted on the tractor, and the tractor may also provide a source of power if the implement is mechanised. Another common use of the term, “tractor unit”, describes the power unit of a semi-trailer truck (articulated lorry).
The word tractor was taken from Latin, being the agent noun of trahere “to pull”. The first recorded use of the word meaning “an engine or vehicle for pulling wagons or ploughs” occurred in 1901, displacing the earlier term traction engine (1859)
History:
The first powered farm implements in the early 19th century were portable engines – steam engines on wheels that could be used to drive mechanical farm machinery by way of a flexible belt. Around 1850, the first traction engines were developed from these, and were widely adopted for agricultural use. The first tractors were steam-powered plowing engines. They were used in pairs, placed on either side of a field to haul a plow back and forth between them using a wire cable. Where soil conditions permitted (as in the United States) steam tractors were used to direct-haul plows, but in the UK and elsewhere plowing engines were used for cable-hauled plowing instead. Steam-powered agricultural engines remained in use well into the 20th century until reliable internal combustion engines had been developed.
In 1892, John Froelich invented and built the first gasoline/petrol-powered tractor in Clayton County, Iowa, USA. After receiving a patent Froelich started up the Waterloo Gasoline Engine Company, investing all of his assets which by 1895, all would be lost and his business resigned to become a failure.
Hart & Parr #3 Tractor
After graduating from the University of Wisconsin, Charles W. Hart and Charles H. Parr developed a two-cylinder gasoline engine and set up their business in Charles City, Iowa. In 1903 the firm built fifteen “tractors”. A term with Latin roots coined by Hart and Parr and a combination of the words traction and power. The 14,000 pound #3 is the oldest surviving internal combustion engine tractor in the United States and is on display at the Smithsonian National Museum of American History in Washington D.C. The two-cylinder engine has a unique hit-and-miss firing cycle that produced 30 horsepower at the belt and 18 at the drawbar.
In Britain, the first recorded tractor sale was the oil-burning Hornsby-Ackroyd Patent Safety Oil Traction engine, in 1897. However, the first commercially successful design was Dan Albone’s three-wheel Ivel tractor of 1902. In 1908, the Saunderson Tractor and Implement Co. of Bedford introduced a four-wheel design, and went on to become the largest tractor manufacturer outside the U.S. at that time.
While unpopular at first, these gasoline-powered machines began to catch on in the 1910s when they became smaller and more affordable. Henry Ford introduced the Fordson, the first mass-produced tractor in 1917. They were built in the U.S., Ireland, England and Russia and by 1923, Fordson had 77% of the U.S. market. The Fordson dispensed with a frame, using the strength of the engine block to hold the machine together. By the 1920s, tractors with a gasoline-powered internal combustion engine had become the norm.
Row-crop tractor history:
The first tractors designed for the ability to fit between rows of crops were made by International Harvester (IH), with development beginning in the 1920s. The first row-crop tractors made by IH were called “Farmalls”. The cultivator mounted in the front so it was easily visible. Additionally, the tractor had a narrow front end; the front tires were spaced very closely and angled in towards the bottom. The back wheels straddled two rows and it could cultivate four rows at once.
From 1924 until 1963, Farmalls were the largest selling row-crop tractors.
To compete, John Deere designed the Model C which had a wide front and could cultivate three rows at once. Only 112 prototypes were made as Deere realized that sales would be lost to Farmall if their model did less. In 1928, John Deere released the Model C anyway, only as the Model GP (General Purpose) to avoid confusion with the Model D when order over the then unclear phone.
Oliver refined its “Row Crop” model early in 1930. Until 1935, the 18-27 was Oliver–Hart-Parr’s only row-crop tractor. Many Oliver row crop models are referred to as “Oliver Row Crop 77″ or “Oliver Row Crop 88″ etc.
Many early row-crop tractors had a tricycle design with two closely spaced front tires, and some even had a single front tire. This made it dangerous to operate on the side of a steep hill, and, as a result, many farmers died from tractor rollovers. Also, early row-crop tractors had no rollover protection system (ROPS), meaning that if the tractor flipped back the operator could be crushed. Sweden was the first country which passed legislation requiring ROPS, in 1959.
Over 50% of tractor related injuries and deaths are attributed to tractor rollover.
Modern row crop tractors have rollover protection systems in the form of a reinforced cab or a roll bar.
Alternative machine types ‘called’ tractors:
The term tractor (US & Canada) or tractor unit (UK) is also applied to:
- Road tractors, tractor units or traction heads, familiar as the front end of an articulated lorry / semi-trailer truck. They are heavy-duty vehicles with large engines and several axles.
The majority of these tractors are designed to pull long semi-trailers, most often to transport freight of some kind over a significant distance, and is connected to the trailer with a fifth wheel coupling. In England this type of “tractor” is often called an “artic cab” (short for articulated cab).
A minority is the ballast tractor, whose load is hauled from a drawbar.
- Pushback tractors are used on airports to move aircraft on the ground, most commonly pushing aircraft away from their parking stands.
- Locomotive tractors (engines) or Rail car movers
The amalgamation of machines, electrical generators, controls and devices that comprise the traction component of railway vehicles
- Artillery tractors
Vehicles used to tow artillery pieces of varying weights.
- NASA and other space agencies use very large tractors to ferry launch vehicles such as booster rockets and space shuttles from their hangars to (and, in rare cases, from) the launchpad.
- A pipe-tractor is a device used for conveying advanced instruments into pipes for measurement and data logging, and the purging of well holes, sewer pipes and other inaccessible tubes.
.
