Harvesters are integrated crop harvesting machines that perform the functions of cutting, threshing, and gathering the grain into storage bins in a single operation.
The main purpose of a harvester, also known as a cutting and sunning machine, is to cut down the rice and lay it in strips in the field. These machines have a simple structure, and lightweight body, and are convenient to transfer, use, and maintain.
However, they have some drawbacks, including low work efficiency, high labor intensity, and significant losses.
One type of harvester is the semi-feed combine harvester, which cuts the rice using a clamping chain that holds the base of the stalk. Only the spike is threshed, resulting in lower power consumption and intact stalks.
However, this model's productivity is not sufficiently high to meet the demands of large-scale harvesting.
In contrast, the full-feed combine harvester feeds the cut rice spike, along with the stalk, into the threshing device.
This design increases productivity and adaptability to various crops. Whether half-feed or full-feed, combine harvesters are equipped with automatic adjustment devices, monitoring instrumentation, and hydraulic systems to enhance their performance and improve the working conditions for the operator.
Combining cutting, threshing, and grain cleaning operations into a single process, these machines achieve a high degree of mechanization and deliver excellent operational quality.
They significantly enhance labor productivity, enabling timely harvesting during the agricultural season and ensuring increased production and yield.
However, due to their complex structure and high cost, the selection of combined harvesters should be based on local economic conditions and technological capabilities.
Another type of harvester is the hand-held harvester. This machine's weight is supported by walking wheels while a person pushes it forward, and the engine drives the cutting and irrigation operations. Its structure and working principle are similar to a portable cut irrigation machine.
The suspended harvester, on the other hand, is attached to the rear of a tractor and driven by the power output shaft, making it suitable for large-scale cutting and irrigation operations. It consists of a frame, saw blade, transmission device, suspension device, and push plate.
When cutting and irrigating, the tractor moves backward at a working speed of 5 km/h, capable of sawing shrubs with a diameter of up to 10 cm.
The horizontal cutting table harvester comprises a paddle wheel, one or two canvas conveyor belts at the front and back, a divider, a cutter, and a transmission device.
During operation, the reciprocating cutter cuts the crop and pushes it back onto the canvas conveyor belt with the assistance of the paddle wheel pressure plate.
The belt then conveys the crop to the left side of the machine. Since the rear conveyor belt is longer than the front one, the crop's head falls to the ground later, and the discharged stalks are neatly laid on the ground in a strip at an angle to the machine's direction of travel.
This arrangement facilitates the easy manual collection and tying of the stalks. The horizontal cutting platform harvester is suitable for rice and wheat harvesting, exhibiting good adaptability to varying growth densities, plant heights, lodging degrees, and yields. It features a simple structure.
However, it has a larger longitudinal size, limiting operational flexibility. It is often used in conjunction with wheeled or walk-behind tractors with less than 15 kilowatts of power, and its cutting width is typically less than 2.0 meters, allowing it to collect 4 to 5 acres of wheat per hour for each meter of cutting width.
Harvesters play a crucial role in modern agriculture by streamlining the harvesting process. Different types of harvesters offer varying advantages and disadvantages, and the selection should consider local economic factors and technological capabilities.
