Disk plows

In disk plows large rotating disks have replaced the share, coulter and mould board. The disks move and turn the soil.

The disk plows have some structural features that allow them to operate where mould board plows cannot work efficiently:

1) on dry, hard ground, that can not be penetrated with shares and coulters;

2) on stony and root lands;

3) on sticky, waxy soils;

4) on stubbles with a large amount of trash.

Disk plows may be classified according to the method of attachment to the tractor. They are mounted, semi-mounted or trailed plows and conventional or reversible plows.

Mounted disk plows are attached to the tractor by 3-point linkage. They can be lifted or lowered by the hydraulic system. Most of them can be fitted in less than a minute.

Semi-mounted disk plows are pulled by the tractor drawbar.

Trailing disk plows have 3 wheels for support. Reversible disk plows are used in areas where it is necessary to turn all furrow in the same direction.

The disks cut the soil more easily and less soil is moved, but the disk plow is often heavier and this may increase the draft¹. Maintenance cost is low. There are no shares to replace or to sharpen². Plow disks last³ for years.

NOTES

¹draft - тяга

²sharpen - заострять

³last - сохраняются

Walking tractor

This universal device can be used both as a tractor and a cultivator. It is supplied with a rotary hoe for inter-row cultivation, traditional and reversible plows, spraying and washing pump, irrigation pump, and cultivators with rigid and spring tines, drills, etc.

The main parts of this machine are:

1. Differential locking device lever.

2. Brake control lever.

3. Gear box control rod to select speeds.

4. Clutch control lever to disconnect wheels and PTO-drive.

5. Adjustable wheels.

This tractor has the following technical characteristics:

Engine - petrol 13 - 15 HP; Diesel 10 - 14 HP;

Starting - electrical;

Gearbox - 6 speeds: 4 forward, 2 reverse;

Wheels - pneumatic: PTO - 2. The upper PTO is synchronized with the gear box, the lower one is independent at two speeds.

Weight - 220 kg.

LESSON 4

COMBINE-HARVESTERS

TEXT A FUNCTIONS OF COMBINE-HARVESTERS

TEXT B TOTAL QUALITY STANDARDS

TEXT C MAIN FAULTS, SERVICING AND MAINTENANCE OF COMBINE-HARVESTERS

GRAMMAR REVISION INFINITIVE, MODAL VERBS, PASSIVE VOICE

TEXT A

FUNCTIONS

OF COMBINE-HARVESTERS

Combine-harvesters are used to harvest various crops. The combine cuts the crop, threshes it, and separates the grain from the straw and chaff.

The mechanism of a combine can be divided into three sections: cutting, threshing and separating the grain from the straw and chaff. The main parts of the cutting unit are a reel, a divider, a cutting bar and an auger.

To cut the crop a reciprocating type cutter bar is used. There is a divider at each side¹ of the cutter bar. It separates the crop to be cut from that, which will be left for the next round². After the crop is cut, the reel directs it to the cutter bar platform. The reel is one of the main parts of the combine. It has tines, which can be angled³ to provide better cutting of the crops. A large auger moves the crop to the centre of the platform.

By means of tines the auger directs the crop to the main elevator. The main elevator lifts the crop to the threshing mechanism.

The threshing mechanism consists of front and rear beaters, a heavy rotating drum and a concave. The main elevator is used to lift the crop to the front beater. It delivers the crop to the drum and concave. The front beater increases the speed of the crop as it moves to the drum.

Threshing takes place between the drum and concave. There are spaces between the concave bars for the threshed grain to fall through to the grain pan. To reduce the speed of the crop as it leaves the cylinder is the task of the rear beater. The rear beater both reduces the speed of the crop and directs it to the separating mechanism. The separating mechanism consists of 2 parts: the straw walkers and the grain sieves. There the grain is separated from the straw. The cleaned grain falls into the grain pan, located under the concave. Then it is directed to the grain tank. Its capacity varies with the type of a combine.

NOTES

¹at each side - на каждой боковине

²for the next round - для следующего хода

³which can be angled - которые могут быть наклонены