Assess your progress in this unit. Say what statements are true about you.

1) I know the meaning of the words from the word list.

2) My listening and reading are good enough to understand most of each text in this unit.

3) I can speak on the topic “Types of excavating machines and their differences.”

Unit 3 EARTH MOVERS: BULLDOZERS, GRADERS, SCRAPERS AND LOADERS

Start up

Match the numbers with the words.

a) fuel tank b) crawler tractor c) air pre-cleaner filter d) exhaust pipe stack e) push frame f) cab g) track h) blade i) diesel engine compartment j) blade lift cylinder

Reading

Text A

Read the text and complete the following sentences.

1) Bulldozers are made up of ……… .

2) Bulldozers are used in ……… .

3) Bulldozers are used for ……… .

BULLDOZERS

A bulldozer, also called a dozer, is a powerful machine for pushing earth or rocks, used in road building, farming, construction, mining, forestry and wrecking; it consists of a heavy, broad steel blade mounted on the front of a tractor.

Sometimes a bulldozer uses a four-wheel-drive tractor, but usually a track or crawler type is employed. The tracks give bulldozers excellent ground holding capability and mobility through very rough terrain. Wide tracks help distribute the bulldozer’s weight over a large area, thus preventing it from sinking in sandy or muddy ground.

The bulldozer blade is curved, and it is also very wide and tall so that it can carry a lot of material. The blade may be raised and lowered by hydraulic cylinders. For digging, the blade is held below surface level; for transporting, it is held at the surface level; and for spreading, it is held above the surface level, as the tractor moves forward.

Bulldozers are used for shallow digging and ditching; short-range transportation of material; spreading soil dumped from trucks; rough grading; removing trees, stumps, and boulders; and cleaning and leveling around loading equipment. A bulldozer is often equipped at the rear with a claw-like device (known as a ripper) to loosen densely compacted materials. A bulldozer alone can do many types of excavation, and it is useful in combination with other machinery in most excavation work.

Vocabulary

Exercise 1. Give English equivalents to the following Russian phrases.

Лесоводство, спереди, гусеничный бульдозер; неровная местность; широкие гусеницы; криволинейный отвал; перемещать большое количество грунта; отвал можно поднимать и опускать с помощью гидроцилиндров; ниже уровня поверхности (земли); перемещение на небольшое расстояние; распределение грунта; грунт, сгруженный с грузовиков; сзади; похожий на коготь; чтобы разрыхлить плотный грунт; вместе с другими машинами.

Exercise 2. Complete the sentences.

1) A bulldozer is a powerful machine for ……… material.

2) It is made up of a crawler ……… and a ……… .

3) A track allows the bulldozer to move over ……… terrain.

4) A bulldozer has a metal plate (known as a blade) used to push large quantities of soil, sand, rubble, or other such ……… during construction.

5) Bulldozers are often used in ……… with backhoes and other digging machines.

Comprehension

Decide if the sentences are true (T), false (F) or there is no information in the text (N). Correct the false sentences.

1) A bulldozer is a powerful and stable earth-moving equipment.

2) The main task of a bulldozer is to push.

3) The blade is mounted at the rear of a bulldozer.

4) Bulldozers perform the "rough grading".

5) The ripper is the long claw-like device on the front of the bulldozer.

6) A bulldozer runs on diesel fuel.

7) Bulldozers are also used for clearing snow on snow-covered roads.

8) The use of tracks divides the heavy weight of the vehicle over a large surface area, thereby decreasing the pressure and facilitating the movement of the bulldozer.

Rendering

Render the text in English.

Бульдозер – самоходная землеройная машина, представляющая собой гусеничный или колёсный трактор с навесным рабочим органом – криволинейным в сечении отвалом. Бульдозер служит для послойного копания, планировки и перемещения (на расстояние 60–150 м) грунтов, полезных ископаемых, строительных и других материалов при строительстве и ремонте дорог, каналов и других сооружений.

Отвалы всех типов Б. оснащаются механизмами с гидравлическим, канатным или электромеханическим приводом для подъёма – опускания, поворотов, наклона (tilting) вперёд – назад. Бульдозеры снабжаются сменным оборудованием (например, рыхлительными зубьями), расширяющим область их применения и повышающим эффективность на отдельных работах.

Listening

Video 6