Combine harvester
The modern combine harvester, or simply combine, is a versatile machine designed to efficiently harvest a variety of grain crops. The name derives from its combining three separate harvesting operations—reaping, threshing, and winnowing—into a single process. Among the crops harvested with a combine are wheat, oats, rye, barley, corn (maize), sorghum, soybeans, flax (linseed), sunflowers and canola. The separated straw, left lying on the field, comprises the stems and any remaining leaves of the crop with limited nutrients left in it: the straw is then either chopped, spread on the field and ploughed back in or baled for bedding and limited-feed for livestock.
Combine harvesters are one of the most economically important labour saving inventions, significantly reducing the fraction of the population engaged in agriculture.
History
In 1826 in Scotland, the inventor Reverend Patrick Bell designed (but did not patent) a reaper machine, which used the scissors principle of plant cutting – a principle that is still used today. The Bell machine was pushed by horses. A few Bell machines were available in the United States. In 1835, in the United States, Hiram Moore built and patented the first combine harvester, which was capable of reaping, threshing and winnowing cereal grain. Early versions were pulled by horse, mule or ox teams.
In a parallel development in Australian saw the development of the stripper based on the Gallic stripper, by John Ridley and others in South Australia by 1843. The stripper only gathered the heads, leaving the stems in the field.
Combines, some of them quite large, were drawn by mule or horse teams and used a bullwheel to provide power. Later, steam power was used, and George Stockton Berry integrated the combine with a steam engine using straw to heat the boiler.
In 1911, the Holt Manufacturing Company of California produced a self-propelled harvester.
In the 1920s, Case Corporation and John Deere made combines and these were starting to be tractor pulled with a second engine aboard the combine to power its workings.
Tractor-drawn combines (also called pull-type combines) became common after World War II as many farms began to use tractors.These combines used a shaker to separate the grain from the chaff and straw-walkers (grates with small teeth on an eccentric shaft) to eject the straw while retaining the grain. Early tractor-drawn combines were usually powered by a separate gasoline engine, while later models were PTO-powered. These machines either put the harvested crop into bags that were then loaded onto a wagon or truck, or had a small bin that stored the grain until it was transferred to a truck or wagon with an auger.
In 1937, the Australian-born Thomas Carroll, working for Massey-Harris in Canada, perfected a self-propelled model and in 1940, a lighter-weight model began to be marketed widely by the company.[12] Lyle Yost invented an auger that would lift grain out of a combine in 1947, making unloading grain much easier. In 1952 Claeys launched the first self-propelled combine harvester in Europe; in 1953, the European manufacturer Claas developed a self-propelled combine harvester named 'Hercules', it could harvest up to 5 tons of wheat a day. This newer kind of combine is still in use and is powered by diesel or gasoline engines. Until the self-cleaning rotary screen was invented in the mid-1960s combine engines suffered from overheating as the chaff spewed out when harvesting small grains would clog radiators, blocking the airflow needed for cooling.
A significant advance in the design of combines was the rotary design. The grain is initially stripped from the stalk by passing along a helical rotor, instead of passing between rasp bars on the outside of a cylinder and a concave. Rotary combines were first introduced by Sperry-New Holland in 1975.
In about the 1980s on-board electronics were introduced to measure threshing efficiency. This new instrumentation allowed operators to get better grain yields by optimizing ground speed and other operating parameters.
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