Bulldozer

A bulldozer is a very powerful crawler tractor equipped with a blade.

Most often, bulldozers are large and powerful tracked engineering vehicles. The tracks give them excellent ground hold and mobility through very rough terrain. Wide tracks help to distribute the bulldozer's weight over large area (decreasing pressure), thus preventing it from

sinking in sandy or muddy ground. Extra wide tracks are known as 'swamp tracks'. Bulldozers have excellent ground hold and a torque divider designed to convert the engine's power into dragging ability , letting the bulldozer use its own weight to push very heavy things and remove obstacles that are stuck in the ground. The Caterpillar D9, for example, can easily tow tanks that weigh more than 70 tons.

Sometimes a bulldozer is used to push another piece of earthmoving equipment known as a "scraper". The towed Fresno Scraper, invented in 1883 by James Porteous, was the first design to enable this to be done economically, removing the soil from the cut and depositing it elsewhere on shallow ground (fill).

The bulldozer's primary tools are the blade and the ripper.

The ripper is the long claw-like device on the back of the bulldozer. Rippers can come singly (single shank) or in groups of two or more (multi shank rippers). Usually, a single shank is preferred for heavy ripping. The ripper shank is fitted with a replaceable tungsten steel alloy tip.

Ripping rock lets the ground surface rock be broken into small rubble easy to handle and transport, which can then be removed and grading can take place.

Also, hard earth can be ripped and decompacted to allow planting of orchards which otherwise could not grow on the land.

The bulldozer blade is a piece of heavy metal plate, installed on the front of the tractor, with the aim of pushing things, handle rough obstacles and shoving sand, dirt and debris. The dozer blade on front of the tractor usually comes in 3 varieties:

A Straight Blade ("S-Blade") which is short and has no lateral curve, no side wings, and can be used for fine grading.

A Universal Blade ("U-Blade") which is tall and very curved, and has large side wings to carry more material.

A "S-U" combination blade which is shorter, has less curvature and smaller side wings. This blade is typically used for pushing piles of large rocks, such as at a quarry.

Exercise 3: Answer the following questions:

1. What is a bulldozer equipped with?

2. Why do bulldozers have excellent ground hold and mobility through very rough terrain?

3. What kinds of work can a bulldozer perform?

4. What tools are mainly used with bulldozers?

5. What can rippers be used for?

6. What aim is the bulldozer blade installed with?

7. What varieties of the dozer blade are there?

Exercise 4. Translate the following words into Russian:

Blade, track, distribute, drag, push, weigh, deposit, ripper, grade, plate, install, shove, curve, pile, shank, quarry, claw, alloy, rubble, debris, fine grading, curvature, sink, through, thus, as.

Exercise 5. Translate from Russian into English:

Карьер, рыхлитель, лезвие, изгибать, куча, гусеница, класть, толкать, выравнивать, распределять, тащить, устанавливать, весить, плита, стойка, оседать, обрезки, каменный лом, сплав, профилирование, клещи, кривизна.

Exercise 6. Match the following words (A) with their definitions (B):

«A»

1. install

2. distribute

3. curve

4. deposit

5. pile

6. push

7. rubble

8. quarry

9. ripper

10. grade

«B»

1. to put in a stated place to be kept safely

2. a mass of broken stones or bricks

3. to place in position and ready for use

4. to make a surface level without obstacles

5. to spread out over a certain area

6. a place from which stone, sand, etc. are dug out

7. a number of objects placed one on top of the other

8. a line without straight lines and angles

9. to use pressure in order to move objects to a different position

10. a machine which turns huge pieces of earth or rock into smaller ones

Exercise 7. Define the functions of the Infinitive and translate the following sentences:

1. The purpose of this device is to transport building materials.

2. This modern equipment helped the builders to increase the efficiency of their work.

3. To lift the loads we utilize cranes.

4. The materials to be used in construction should be durable.

5. The rails were laid to mount a crane on them.

6. They will use a more powerful engine.

7. To operate new handling equipment is not very easy.

8. It is necessary to test machines.

9. To design a fork lift truck with a number of practical advantages was the task of our engineers.

10. The aim of his work is to test the truck for forward and lateral static stability.

11. The machines to be used on a construction site are cranes, trucks, conveyors, etc.

Exercise 8. Translate the following sentences, paying attention to Complex Object:

1. We know the new design of a crane to be ready.

2. The students expect their practical work to take place in summer.

3. Engineers believe a crane to be widely used in this project.

4. Builders consider elevators to be convenient in house construction.

5. They suppose the experiment to be a success.

6. We know lubricants to reduce friction.

7. I believe them to know this subject well.

8. The engineers proposed a rail mounted crane to be installed at this site.

Exercise 9. Translate the following sentences, paying attention to Complex Subject:

1. Machines are known to have been used since early times.

2. Modern scraper is claimed to be cheap and very compact.

3. Engineers are expected to test the new equipment next week.

4. These devices are considered to be very efficient.

5. This engine is claimed to be the best.

6. This gearbox has proved to be completely reliable.

7. Crawler tractors proved to be suitable for excavating and earthmoving.

8. This tractor seems to be widely used in construction.

9. The new power station is reported to have been put into operation.

10. He seems to be working at a new project.

Exercise 10. Translate the following sentences, paying attention to the infinitive:

1. The aim of building a gas engine was to overcome the drawbacks of the steam engine.

2. As a means to produce material wealth, machines are invaluable in the process of production.

3. A man can carry a maximum of 50 kg at a rate of 3- 5 km/hr.

4. To handle small loads a hook may be attached directly to the free end of the rope.

5. To drive a car in a big city is very difficult.

6. Tower cranes are used to install separate elements.

7. These materials are to be handled by a crane.

8. It is important to improve technical and operating characteristics of machines.

9. This temperature is considered to be high enough to burn heavy fuel.

10. We know a water- cooled engine to be used in many cars.

Exercise 10. Analyze the sentences underlined in Text A. Find Infinitives and define their function.

Exercise 11. Translate the text without a dictionary:

Text B