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Forage Harvester

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Agricultural Equipment
1997 John Deere 6910 Forage Harvester
A forage harvester is a piece of agricultural equipment used to harvest plants to make silage for livestock feed. Silage can be made of grass, corn or other plants chopped into small pieces and compacted into a storage silo. The collected material ferments inside the silo, which is vacant of oxygen. This fermented material is then fed to the farm livestock. (If oxygen enters the silo it can rot the silage.)

Forage harvesters are generally classified into two categories: trailer units towed by tractors and self-propelled models. Of these two categories, they can work as cut-and-blow or cut-and-throw models. Cut-and-blow is more versatile in its ability to mount a secondary cutting screen providing a more consistent material size. A recutter screen cannot be mounted on cut-and-throw and is required to both cut and throw the forage material into the holding wagon. It is not equipped with a separate fan.

There are also two different types of cutter heads, the drum or cylinder cutter and the flywheel. Each is model is also equipped with wheels, an axle, frame, blower, and a feeding apron or roll.

Holding wagons can be attached or follow beside the forage harvester. Once full the wagon is towed from the field back to the silo and unloaded. Meanwhile, a new wagon will begin being filled by the harvester.

Depending on the type of crop being harvested a different blade or cutting attachment may be needed.

Manufacturer and model harvest rates vary, but on average, modern machines can cut as much as 1,200 tons of silage per day.[1] Common manufacturers include Case IH, John Deere, Massey-Ferguson, and New Holland.

Contents

[edit] History

According to the American Society of Agricultural and Biological Engineers (ASABE) the first official forage harvester was patented by William J. Conroy of Aylmer, Quebec, Canada in 1891.[2] This first machine consisted of a sickle that cut the crop, elevating it into a cylindrical curved-bar cutterhead. While it failed commercial success it was the starting point of a very important piece of farm equipment.

In 1926, a professor from the University of Wisconsin Agricultural Engineering Department, Floyd Waldo Duffee, built a silo filler with an attached hay loader. After presenting the design to the ASABE, J.I. Case Co. agreed to construct a model Duffee could conduct tests on and improve.

Meanwhile, the Fox River Tractor Co. was also developing its own forage harvester, designed by its chief engineer, Erwin W. Saiberlich. The first Fox River model sold in 1932. The company later redesigned and re-released it in 1936.

The Saberlich forage harvester was so popular that nearly all models until the mid-1980s followed its primary design.[3]

Wisconsin agricultural and construction manufacturing company Gehl produced the first self-propelled forage harvester in the early 1950s.[4]

[edit] Features/How it Works

[edit] Drum or Cylinder Cutting Mechanism

The drum or cylinder cutting mechanism includes a shaft with two or three spiders, two to eight knives, and a shear plate. Spiders are fastened to the shaft and the knives are bolted to the rims of the spiders. Knives can be loosened or tightened accordingly. They can also be removed for sharpening.

Promill Apollon 4x4 Spinach Harvester
The drum sits near the end of the conveyer apron. Each knife is designed to nearly scrape the edge of the sharp shear plate. Because of the spiral shaped knife, the cutting action between it and the plate is a shearing action. (Shear plates can be changed when the edges dull.) The cut material is blown up the discharge spout into a holding wagon.

[edit] Flywheel Cutting Mechanism

The flywheel cutting mechanism includes a heavy boiler plate, knife holders and adjustment devices, two to six knives, about four paddles for blowing, and a shear plate. The boiler plate, which must be centered and balanced, is fastened to a heavy cross shaft. Four to six knife holders are riveted or welded to the plate, and the knives themselves are bolted to the holders. Each knife is generally about half an inch thick, sharpened on the beveled side. The flat side of the knife faces the shear plate. The closeness of the knife to the plate is extremely important. There should be just enough room between to slide a piece of paper.

The flywheel spins, creating enough energy to cut large pieces of forage. Paddles attached to the wheel push sheared forage up the discharge spout into the holding wagon.

Knives are removed in pairs to maintain stability. Fewer knives create larger cuts/pieces of forage.

[edit] Common Manufacturers

[edit] References

  1. Harvester. Tutorgig. 2008-09-24.
  2. Invention of the Pickup Forage Harvester. ASABE. 2008-09-24.
  3. Invention of the Pickup Forage Harvester. ASABE. 2008-09-24.
  4. Gehl Company. Answers.com. 2008-09-24.