EXCAVATORS

An excavator is an earth-digging machine designed for making trenches and pits, as well as for carrying out other kinds of earthwork involved in construction. A single bucket excavator is an intermittent action machine. Its working cycle consists of the following operations: cutting some amount of earth from a solid mass, carrying the dug soil to a dumping place, emptying the bucket and returning to the initial position.

The fundamental mechanism of an excavator consists of the undercarriage which includes the tracks or wheels, the frame and the final drive. The final drive has a hydraulic motor and gears that provide drive to the tracks. The operator’s cabin, engine, counterweights, hydraulic and fuel tanks are attached to the undercarriage to enable the excavator to swing 360 degrees without hindrance.

The workgroup of an excavator includes the boom, dipper or arm, and attachment (for example, bucket, auger or breaker). Mostly the boom can move only up and down, or in addition also shift towards the left and the right of the machine. An arm is attached to the boom end that imparts the force for digging into the ground. A bucket is fixed at the arm end for carrying the soil. In addition to the buckets, there are numerous other categories of different attachments and devices that are used for boring, crushing, lifting and ripping. This expands hydraulic excavator capabilities far beyond excavation tasks with buckets.

Vocabulary:

earth-digging ['WT'dIgIN] a. – землеройный

design [dI'zQIn] v.– проектировать, конструировать

intermittent ["Intq'mItqnt] a. – периодический

undercarriage ['Andq"kxrIG] n.– ходовая часть, шасси

tracks [trxks] n. – гусеницы

frame [freIm] n. – рама

final drive ['fQInl 'drQIv] – главная передача

gear [gIq] n.– шестерня, зубчатая передача; передаточный механизм, привод

engine ['enGIn] n. – двигатель

counterweight ['kQuntq"weIt]] n. – противовес

fuel tank ['fjuql 'txNk] – топливный бак

swing [swIN] n. v.– поворот; поворачивать

boom [bHm] n. – стрела

dipper ['dIpq] n. – ковш

auger ['Lgq] n. – бур, сверло

breaker ['breIkq] n. – дробилка

boring ['bLrIN] n. – бурение, сверление

crushing ['krASIN] n.– раздавливание, дробление

ripping ['rIpIN] n. – рыхление

Answer the following questions:

1. What are the main functions of an excavator?

2. What does the working cycle of an excavator consist of?

3. What does the undercarriage include?

4. What parts of an excavator do you know?

5. What mechanisms does the working group consist of?

6. How can the boom move?

7. How can an excavator be converted?

8. What expands hydraulic excavator capabilities?

НТТС (IV семестр)

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