Modern tractors

The tractor is a basic and most useful machine. At present¹ the main function of tractors is to provide mobile power for a wide range of agricultural operations and all principal industries.

Tractors may be used for numerous tasks in agriculture such as plowing, planting, cultivating, fertilizing, harvesting as well as² for transport and to supply power for machinery through the PTO-shaft.

It is impossible to design a tractor performing all these jobs with the same³ efficiency and economy. That's why tractors are provided with certain features. All modern tractors can be classified according to the work they perform. The main groups are agricultural tractors, powerful road transport tractors and special tractors. Tractors may be also classified as wheel tractors and track laying tractors. Agricultural tractors include general-purpose or row-crop tractors and garden tractors. General-purpose tractors can pull agricultural mounted or trailed machinery. Various implements are adjusted on the tractor by means of 3-point linkage. Tractors operate with plows, drillers, mowers, harrows, etc. Row-crop tractors include both three wheel and four-wheel machines, which are able to operate between crops drilled in rows. They are designed for planting, cultivating and harvesting corn, cotton and vegetable crops. Garden tractors are constructed for work in gardens and orchards. They are lower than the standard four-wheel tractors in order to operate closer to trees and vines. And the tyres are made of smaller diameter because orchard soils are light and loose⁴.

Powerful transport tractors have higher road speed. They are equipped with load carrying platforms.

Special tractors are equipped with auxiliary⁵ devices, such as graders⁶, blades⁷, scoops⁸, diggers⁹, etc.

Tractors can differ in model and in size, but they must have some typical constructional features. They are: a powerful engine, a transmission system, a drawbar, a 3-point linkage to mount implements, a hydraulic system to lift and lower machinery, a PTO-shaft to drive machines, and pneumatic wheels or tracks.

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Date: 2015-10-18; view: 1073; Нарушение авторских прав