Grain Combines

Grain Combines


This combine has a grain table on the front for harvesting wheat.

This combine has a corn header because it is harvesting corn.

The combine harvester[1] or simply, combine, is a machine that combines the tasks of harvesting, threshing, and cleaning grain crops.

The combine:

1. Cuts the entire stalk

2. Separates the grain from the stalk

3. Discards the debris out the back of the machine

4. Stores the grain in the top.

  • The debris left behind on the field is the remaining dried stems and leaves of the crop.

    • These are either chopped and spread on the field or baled for feed and bedding for livestock.
  • The head of the combine can be changed to a grain table[2] (see top picture) for harvesting small grains such as wheat and soybeans.
  • A corn header[3] (see bottom picture) is used for corn.

When the grain bin on top of the combine is full, a grain wagon[4] can drive up beside the combine and the boom on the side of the combine (seen on the bottom picture) will put the grain from the bin into the wagon while the combine is still operating.

Similar to the cotton picker[5], grain combines use GPS[6] to ensure they are getting maximum coverage of the header from pass to pass. This optimizes their harvesting efficiency as well as reducing their time in the field and fuel consumption.

Grain fields are usually very large. Perfectly straight paths are desired for planting and harvesting grain. The GPS interfacing system on these John Deere combines creates a straight line path in two ways:

1. The GPS asks the user to set a point A then drive to the end of the field and set a point B. The GPS then creates an imaginary line between these two points and asks the user how wide the header is that they are using. The header width will tell the GPS how far aparth the imaginary lines should be. This is called the swath width. The GPS will create imaginary lines exactly parallel to the initial AB line throughout the remainder of the field.

2. The GPS asks for a point A and an azimuth[7]. An azimuth is a heading relative to true North. An imaginary line will be created from this information. Then the machine will follow this line through the field.

Grain harvesters are also equipped with yield monitors[8] operating similarly to the cotton picker. The difference is that the grain harvesters use an impact plate at the top of a grain elevator to compute an actual yield.

Photo by dhwright / CC BY

Photo by wilson-fam / CC BY