The Purpose of a Corn Combine
A field of corn contains hundreds of rows of corn plants, and the plants hold the ears of grain until they are harvested. Before harvesting combine machines were invented, corn was harvested by hand. Hand harvesting meant that each ear had to be pulled from the corn stalk, and hauled to a barn or storage bin. The husks had to be removed. The dried corn kernels had to be shelled, or removed from the cob, before they could be ground for livestock feed. Modern corn combine harvesters perform all of these tasks and more as they are driven through the fields. Field corn that is harvested with a combine machine is dry on the stalk, and not watery and soft like sweet corn.
The Header and Reel
The header is the front of the corn combine, and is divided into pointed projection arms that are set to match the spacing of the corn rows. Each row of corn will be fed into the combine between the arms. Combines may have row capability of 12, 16, 24 or more rows. Immediately behind the header arms is a wheel called a reel, which pulls the corn stalks into the machine.
The Cutter Bar and Conveyors
The cutter bar is just behind the header, and it extends the entire width of the header. As the corn feeds into the machine, the cutter bar moves back and forth and cuts off the stalk. The cut stalks are moved into the machine by augers, or rotating bars with large threads similar to huge screws. A conveyor moves the corn stalks further into the main part of the combine.
The corn then meets the threshing drum, a large spinning cylinder that breaks apart the corn plant and beats the kernels of corn off the cobs. The threshing area vibrates to shake the kernels away from the chaff (stalks and cobs).
Sieve and Straw Walker
The corn kernels fall through holes in a huge sieve and into the collection chamber. The straw walker is another conveyor that moves the stalks and cobs towards the back of the combine. The straw walker continues to vibrate and shake more corn kernels into the collection bin.
When the collection bin is full, a tractor pulling a trailer pulls up alongside the combine. Corn is moved up a long pipe called an unloader. The corn falls from the unloader chute into the trailer. The combine continues the harvest, and the tractor takes the trailer of corn to be loaded into a nearby truck.
Another conveyor moves the chaff out the back of the combine. A spinning spreader throws the chaff out behind the machine, dispersing it over the field.