Classification of Tractors

The TRACTOR is a wheeled or tracked self-propelled vehicle used as a power means for moving agricultural, road-building, and other machines equipped with special tools, and also for towing trailers. The tractor engine can be used as a prime mover for active (moving) tools or stationary farm machinery through the intermediary of the power takeoff (PTO) shaft or belt pulley.

The uses of the tractor in agriculture are many, and so different types of tractor are need­ed to do different types of farm work. Farm tractors are classified as follows:

as то purpose, modern farm tractors are classed in three groups: general-purpose (land utility) tractors, universal-row-crop (row-crop utility) tractors, and special-purpose tractors.

Land utility tractors are used for major farm operations common to the cultivation of most crops, such as tillage, discing, general cul­tivations, harrowing, sowing, and harvesting. The tractors are characterized by a low ground clearance, increased engine power, and good traction, thanks to their wide tires or tracks enabling them to develop a high pull.

Universal-row-crop tractors are intended for row-crop work, as well as for many other field tasks. For this purpose, some row-crop utility tractors are provided with replaceable driving wheels of different tread widths -.wide for general farm work and narrow for row-crop work. In order not to damage plants, the tractors have u high ground clearance and a wide wheel track that can be adjusted to suit the particular inter-row distance.

Special-purpose tractors are modifications of standard land or row-crop utility tractor models and are used for definite jobs (e.g., in vineyards, cotton fields) or for various jobs under certain conditions (e. g., on marshy soils, hillsides). Thus, special tractors used to mechanize the cultivation of cotton have a single front (steerable) wheel, swamp tractors are equipped with wide tracks enabling them to operate on marshy soils, and hillside tractors are designed to work on hillsides sloping at up to 16°.

AS TO THE DESIGN OF THE RUNNING GEAR, tractors are divided into crawler (track-laying) and wheeled types.

Crawler tractors are distinguished by a large ground contact area and therefore have a good track adhesion; they crush and compact the soil insignificantly. Such tractors show a high cross-country power and are capable of developing a high pull.

Wheeled tractors are more versatile and can be used for both field and transport work, but their traction is lower than that of crawler tractors.