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in agriculture, a device for attaching several machines to a tractor in order to use the pulling force of the tractor efficiently and to increase the productivity of the unit. Hitches may be general-purpose, special-purpose, trailer, semimounted, or mounted.
General-purpose trailer hitches are used to connect tractors with trailed machines. They consist of two or three beams equipped with extension arms and support wheels and hinged to follow the terrain irregularities better. The machines and extension arms are attached to the beams with clamps that can be moved to ensure correct positioning of the machines or equipment in the unit. The hitch has a tongue for attachment to the tractor. Special-purpose hitches do not usually have wheels; they are composed of links that join the machines to each other, as in plowing combines.
Semimounted hitches are used to attach a tractor to a unit of three mounted machines, each with a working width of 1.8–2.8 m. One machine is fitted to the mounting system of the tractor, and the two others are attached to side mountings on the hitch, similar to the tractor’s own mounting system. Each mounting on the hitch is equipped with a hydraulic cylinder that is operated by the tractor’s hydraulic system; it is used only for lifting the mounted machine. The machine is lowered by its own weight. The proper spacing of machines with different working widths can be achieved by moving the carriage of the hitch’s mounting mechanism along the beam.
A general-purpose hitch can be used to mount harrow units on tractors of small and medium capacity. The harrow units are attached to the post and brackets of the mounting by means of a hinged brace, two long chains, and one short chain. In order to mount harrow units of different working widths, the brackets of the mounting are moved along the beam. One hitch beam can carry three toothed harrow units or two latticed harrow units. A hitch beam may be extended by inserting two tubes in openings in both sides of the beam. The tubes are smaller in diameter than the beam and are welded to brackets for mounting one toothed harrow unit each, for a total of five harrow units.
A. D. UGAROV