Combine harvester

The combine harvester, or simply combine, is a machine that harvests, threshes, and cleans grain plants. The desired result is the seed (such as canola or flax) or grain (such as oats, wheat, or rye); a byproduct is loose straw, the remaining husk of the plant with all nutrients removed. The combine was patented in 1834 by Hiram Moore, the same year as Cyrus McCormick was granted a patent on the mechanical reaper.

Sidehill levelling

An interesting technology is in use in the Palouse region of the Pacific Northwest in which the combine is retrofitted with a hydraulic sidehill levelling system. This allows the combine to harvest the incredibly steep but fertile soil in the region. Hillsides can be as steep as a 50% slope. Gleaner, Case/International Harvester, John Deere and others all have made combines with this sidehill levelling system and local machine shops have fabricated them as an aftermarket add on. Linked pictures below show the technology.

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The first levelling technology was Developed by Holt Co., a California firm, in 1891. Ag Power Mag, Sept 2001 Many Years later modern levelling came into being with the invention and patent of a level sensitive mercury switch system invented by Raymond (Haywire) Hanson in 1946. Rahco.com, 2005. Hanson's company Rahco, Inc. still produces levelling systems exclusively for John Deere combines.

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Sidehill levelling has several advantages. Primary among them is an increased threshing efficiency on sidehills. Without levelling grain and chaff slide to one side of separator and come through the machine in a large ball rather than being separated, dumping large amounts of grain on the ground. By keeping the machinery level the straw-walker is able to operate more efficently and this problem is eliminated for more efficient threshing. Case International produced the 453 combine which leveled both side-to-side and front-to-back thus enabling efficient threshing whether on a sidehill or climbing a hill head on.

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Secondarily, levelling changes a combine's center of gravity relative to the hill and allows the combine to harvest along the contour of a hill without tipping over. The danger is very real on the steeper slopes of the region and it is not uncommon for combines to roll on extremely steep hills.

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Currently sidehill levelling is on the decline with the advent of huge modern machines which are more stable due to their width. These modern combines use the rotary grain separator which makes leveling less critical. Most combines on the Palouse are equipped with dual drive wheels on each side to stabilize the machine.

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