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Hydrostatic Transmission Service LLC

The Hydrostatic Combine Harvester

The Hydrostatic 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. Early combines, some of them quite large, were drawn by horse or mule teams and used a bull wheel to provide mechanical power. Tractor-drawn, PTO-powered combines were used for a time. These combines used a shaker to separate the grain from the chaff and straw-walkers (grates with small teeth on an excentric shaft)to eject the straw while retaining the grain. Tractor drawn combines evolved to have separate gas or diesel engines to power the grain separation. Today's combines are self-propelled and use diesel engines for power. A significant advance in the design of combines was the rotary design. Straw and grain were separated by use of a powerful fan. Rotary combines were introduced in the late 1970's. About this time 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.

Contents [hide] 1 Crop heads  hydraulic operated 2 Sidehill levelling  hydrostatic transmission 3 Maintaining threshing speed  hydrostatically 4 The Threshing Process  variable speed hydrostatic transmission 5 Combine harvesters in popular culture  using hydrostatic transmissions 6 External links

Crop heads

A John Deere 9410 Hydrostatic Combine set to harvest Oats

A  Hydrostatic combine harvesting corn

Hydrostatic Combines are equipped with removable heads that are designed for particular crops. The standard head, sometimes called a grain platform, is equipped with a sickle bar mower, and features a revolving reel with metal or plastic teeth to cause the cut crop to fall into the head. A cross auger then pulls the crop into the throat. The grain platform is used for many crops, including grain, legumes, and many seed crops.

Wheat heads are similar except that the reel is not equipped with teeth. Some wheat heads, called "draper" heads, use a fabric or rubber apron instead of a cross auger. Draper heads keep the crop orientation uniform, feeding grain headfirst into the throat, which allows slightly more efficient threshing.

Dummy heads feature spring-tined pickups, usually attached to a heavy rubber belt. They are used for crops that have already been cut and placed in windrows.

While a grain platform can be used for corn, a specialized corn head is ordinarily used instead. The corn head is equipped with snap rolls that strip the stalk and leaf away from the ear, so that only the ear (and husk) enter the throat. This improves efficiency dramatically since so much less material must go through the cylinder. The corn head can be recognized by the presence of points between each row.

Occasionally rowcrop heads are seen that function like a grain platform, but have points between rows like a corn head. These are used to reduce the amount of weed seed picked up when harvesting small grains.

Self propelled Gleaner combines could be fitted with special tracks instead of tires to assist in harvesting rice.

Sidehill levelling Using Hydrostatic Drive Combines

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.

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.

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.

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.

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.

Maintaining threshing speed using Hydrostatic Transmissions

Claas Lexion 570

Another technology that is sometimes used on combines is a continuously variable Hydrostatic transmission. This allows the ground speed of the machine to be varied while maintaining a constant engine and threshing speed. It is desirable to keep the threshing speed since the machine will typically have been adjusted to operate best at a certain speed.

The Threshing Process, is adjusted using a Hydrostatic Drive

Despite great advances mechanically and in computer control, the basic operation of the combine harvester has remained unchanged almost since it was invented.

First of all the header, described above, cuts the crop and feeds it into the concave. This consists of a series of rasp bars fixed across the path of the crop and in the shape of a quarter cylinder, guiding the crop upwards through a 90 degree turn. Moving rasp bars pull the crop through the concave and separate the grain from the straw. The grain heads fall through the fixed rasp bars onto the sieves. The straw exits the top of the concave onto the straw walkers.

There are usually two sieves, one above the other. Each is a flat metal plate with holes set according to the size of the grain. The holes in the top sieve are set larger than the holes in the bottom sieve. Anything that falls through the bottom sieve is assumed to be grain, and is transported to the grain tank.

The sieves are mounted at a slight incline and shake, further separating the grain. A powerful fan blows from the front of the sives to remove chaff (wheat) or haynes (barley). If the fan is set too high it will blow grain off the back of the sives and out of the combine. If it is set too low then chaff/haynes will be present in the grain.

Heavy material, e.g., unthreashed heads, fall off the front of the sieves and are returned to the concave for re-threshing.

The straw walkers are located above the sieves, and too have holes in. Any grain remaining attached to the straw is shaken off and falls onto the top sieve.

When the straw reaches the end of the walkers it falls to the floor. A straw chopper may be fitted if the straw is unwanted.

Setting the concave clearance, fan speed, and sieve size is critical to ensure than the crop is threshed properly, the grain is clean of debris, and that all of the grain entering the machine reaches the grain tank. ( Observe, for example, that when travelling uphill the fan speed must be reduced to account for the shallower gradient of the sieves.)

Combine harvesters in popular culture, all use hydrostatic Drives

• British Scrumpy and Western group The Wurzels had a number one hit in 1976 with The Combine Harvester. It takes the form of a love song from the point-of-view of a farmer who proposes marriage to his girlfriend, offering to give her the key to the "brand-new combine harvester" to use on her 43 acres of arable land.
• Grand Theft Auto: San Andreas features combine harvesters. CJ had to use one to bring to his friend on some mission.

External links for hydrostatic Drives

• Pictures of combines with corn and wheat heads
• History of Sunshine Harvesters - Museum of Victoria, Australia
• The IH 151 an early levelling machine
• Pictures of Gleaner levelling combines  hydrostatically driven
• Excellent picture of a levelling John Deere with the header removed to show the modified undercarriage and extreme leveling ability as well as pictures of the region

Combine harvesters in popular culture

• British Scrumpy and Western group The Wurzels had a number one hit in 1976 with The Combine Harvester. It takes the form of a love song from the point-of-view of a farmer who proposes marriage to his girlfriend, offering to give her the key to the "brand-new combine harvester" to use on her 43 acres of arable land.
• Grand Theft Auto: San Andreas features combine harvesters. CJ had to use one to bring to his friend on some mission.

External links

• Pictures of combines with corn and wheat heads
• History of Sunshine Harvesters - Museum of Victoria, Australia
• The IH 151 an early levelling machine
• Pictures of Gleaner levelling combines
• Excellent picture of a levelling John Deere with the header removed to show the modified undercarriage and extreme leveling ability as well as pictures of the region

• Retrieved from "http://en.wikipedia.org/wiki/Combine_harvester"

Categories: Agricultural machinery | Engineering vehicles

Often when IH combines are discussed the Axial-Flow System comes to mind. International produced walker combines through 1976. One of the last walker machines was the 815 combine. The 815 came with grain header sizes between 10 and 24 feet and corn heads 4 and 5 row wide. The 815 came with a 144-hp gas or 128-hp diesel engines. A large 133 bushel grain tank was standard. One of the advantages of the 15 series combines was their low profile design which permits movement through 12-ft high openings.    

It took 15 years and a million man hours to design , build and test but in
 1977 International  Hydrostatic Harvester introduced the 1440, 1460, 1480, and later
 the 1420 Axial-Flow Hydrostatic driven combines series. The Axial-Flow Hydrostatic System featured a single
 in-line rotor with impeller on the front rotor and a stationary rotor
 housing with concaves and separating grates. This simple system the
 cylinder, rear beater and straw walkers of the IH 15 series conventional
 combines.  

The 1977 and 1978 Axial Flow Hydrostatic driven Combines continued to use the 810 grain header series used on the late 15 series combines.  In 1979 the 820 series headers were introduced.

International Harvester's First Generation of Self-Propelled Soon to be Hydrostatic Driven Combines

Little Did He Know,That Hydrostatic Power would Follow 

In July 1831 Cyrus Hall McCormick launched his reaper which allowed for the mechanical harvest of grain. Labor time in the field was greatly reduced by the McCormick reaper and it brought sweeping changes to harvesting practices in the 19th century.  McCormick Harvesting Co. and several reaper other companies formed in the second half of the 19th century and competed against each other fiercely. On August 12, 1902 Mccormick Harvesting and four other major reaper companies in a major $120 million agreement merged into one Company named International Harvester.  The companies forming IHC included the Mccormick Harvesting Machine Company, Deering Harvester Company, Plano Machine Company, Champion, Wardner, Bushnell & Glessner Company and the Milwaukee Harvester Company.   In 1981 the International Harvester Corporation celebrated its 150th Anniversary.  Combines  marked an important part of International Harvesters machine linage and business.  Today CaseIH carries on over 170 years of harvesting tradition founded in McCormick's introduction of the first practical reaper.

IH 1440 Combine Hydrostatic driven

Jim Schroer an IH enthusiast, Service Technician at Pioneer Garage, (a CaseIH dealership in South Dakota) and well known mechanical tip person on various internet machine talk boards has authored a detailed history of the 25 years of the Axial Flow combine for Toy Tractor Show.com.  Jim's articles show the impressive mark the Axial-Flow combine has made on grain harvesting. Before we look at one of the most modern harvesting innovations from the proud red line we will look back at the harvesting heritage of International Harvesters self propelled combines.