Main faults of combine-harvesters

TEXT C

EXERCISES

Active Vocabulary to Text В

NOTES

¹robust - крепкий

²ensure - гарантировать

³backbone - основа

⁴sure-footed - устойчивый

⁵progress - продвигаться вперед

chassis - шасси	clearance- зазор
distribution - распределение	valuable - ценный
pin-point - точно определять	even - редкий
range - диапазон	output - производительность
handle - манипулировать	enable - давать возможность
layer - слой	ample - достаточный, обширный
plate - обшивать металлическим листом	volume - количество, объем, емкость

1. Answer the questions.

1. Why has the MF combine taken an impressive lead in combine design?

2. Why is grain always separated from straw with the greatest efficiency?

3. Why can the MF combine give long service and unequalled reliability?

2. Find in the text the passages where:

1) combine chassis, 2) cylinder, 3) hydrostatic transmission, 4) grain table, are described.

Write out the words you will need to characterize these devices. Give your short characteristics.

3. Find passages about concave, sieves, and straw-walkers in the text. Reread them and give your commentary using:

I think; As for me; In my opinion; As far as I understand.

4. Make up the plan of the text. Divide it into some logical parts and entitle them. Define the main idea of each part.

5. Define the main idea of the text and summarize it in 2-3 sentences.

6. How do you interpret the title of the text? Try to give your own title.

7. Retell the text according to your plan.

Testing procedures help to detect the main faults and find out the type, and amount¹ of servicing and maintenance. The main faults are: the damage to the header, the connecting rod, bearings, reel rotation variator, the cutter bar, and the knife. Also we can find fractures, distortion and wear of the pins, bushings, auger parts, bearings and gears, and the shafts of the drums and concaves with the decks. Serious problems can be caused by faults in the elevator, the straw-walkers, the sieves, and the coupling parts of the drive axle, the differential, the reducer, and the gearbox.

To eliminate all these faults you should do the following: first improve² the header distortion by heating and fixing³ it. The cutting bar damages result in the cutting quality, so change or improve the knives. Use the hydra cylinder with the lever to avoid the carcass distortion. Examine the elevator carefully, and define the length of the chains. To eliminate beater faults dismantle it. Replace worn bearings, shafts, and bearing bodies. Use clamps to fix the concave, and restore the plates form. Cut away damaged straw-walkers and restore the initial form of the crankshaft. The quality of repair depends on the right assembly of the gearbox, reducer, steering gear clutch and other parts.

Controls and adjustments of all parts provide a perfect operation state for a combine harvester. The even flow⁴ of the crops to the drum and concave is impossible without correct adjustment. Incorrect setting of the pick-up reel will cause large cutter bar losses. It is necessary to provide the contact between the reel and the straw and more than that the reel speed should be faster than the forward speed of the combine.

When you deal with laid crops⁵ the reel should be set well forward. The cutter bar and the knife must be in good condition. You should hold the cutter bar at the height of 3 in. above the ground. But some combines are equipped with an automatic cutting height control system. This provides a regular stubble height.

In heavy straw crops there is a problem of excessive loss of grain over the back of the straw-walkers. To avoid it, reduce forward speed or raise the cutter bar a little.

Adjust the distance between the auger and the platform to prevent blockages of straw on the auger, depending on the crop conditions. Regulate the drum and concave to achieve well threshed grain. Take into account the crop, its conditions and moisture content. Minimize cylinder speed to give complete threshing. Otherwise all the grain won't be removed from the ears. High cylinder speeds will crack the grain.

To give complete threshing makes the concave clearance as wide as possible. A wide concave clearance leaves the grain in the ears. A narrow clearance will crack the grain. But you should keep in mind that the concave clearance should be wider at the front than at the back and this is controlled automatically.

Дата добавления: 2014-10-17