The mechanization. Combine-harvesters

The combine harvester cuts the crop, threshes it, separates the grain from the straw and chaff.

The mechanism of a combine harvester can be divided into five sections.

To cut the crop a reciprocating tyre cutter bar is used. There is a divider at each side of the cutter bar. It separates the crop to be cut from that which will be left for the next round.

The threshing mechanism consists of a front beater, a heavy rotating drum, a concave, and a rear beater.

All combines do not have a front beater.

Threshing takes place between the drum and concave. There are spaces between the concave bars, so the threshed grain can fall through on the grain pan.

The separating mechanism consists of two parts: the straw walkers and the grain sieves.

parts: the straw walkers and the grain sieves. The grain is separated from the straw by the rising and falling action of the straw walkers. They are driven by two crankshafts.

Grain tank capacities vary from 1 to 20 tonnes.

The combine harvester must be set to suit various crops and harvesting conditions.

Both speed and position of the reel need adjustment. Working in a standing crop the reel should contact the straw below the ears.

. In heavy straw crops there is a risk of feeding too much material into the combine which may result in the loss of grain over the back of the straw walkers.