VI. Translate the following sentences paying attention to the Infinitive.

1.The frame to be made of U-shaped sections provides support for the engine, the body, the wheels and the power-train members.

2. Shamshurenkov was the first to invent the first vehicle.

3. Internal combustion engines are the principal power installations to be employed in mobile and self-propelled road-making machinery.

4. A hoist is a simple suspension-type small-size mechanism to be used for assembling machines.

5. Mamin was the first to invent an internal combustion engine.

6. Counterweight (противовес) is mounted to compensate for the weight of the boom and part of the load to be lifted by the crane.

VII. Read and translate the following text.

Й

Tower cranes

Tower cranes are extensively used in construction. They are employed to lift materials, parts and whole structures to be used at construction, to install separate elements, and for loading and unloading operations.

Tower cranes are provided with hoisting, traveling and luffing and jib mechanisms. These cranes are classified by:

a) the load moment: 4, 16, 25, 40, 60, 100, 160 and 250 ton-meters.

The load moment is the product of the weight being lifted by the outreach.

b) the number of working movements: three movements (hoisting, slewing, traveling) or four movements (the same plus luffing and jibbing);

c) the design of the revolving structure: with an upper and lower revolving head; d) the arrangement of the counterweight: at the top or at the bottom.

A tower crane consists mainly of support 1, tower 2, revolving structure 3, counterweight 4, boom 5, and controls (Fig.3). The support carries the traveling

Fig. 4. Tower cranes

mechanism. The tower carries the operator`s cab and some of the mechanisms. It is designed as a latticed steel framework or is made of large-diameter steel tubes.

A counterweight is mounted to compensate for the weight of the boom and part of the weight of the load to be lifted by the crane.

The operating equipment consists of the boom, a hoisting pulley and a load handling attachment, usually a hook.

According to the design of tower, cranes are classified into the following two main groups. The first group includes cranes with the revolving head and the counterweight mounted at the top (Fig.4a). The stationary tower is a metal framework consisting of several sections. The rigid support is made in the form of gantry 1 on traveling wheels. For the transportation this crane is split into separate large units and is then assembled again at the new site. The operator`s cab is built into the middle of the tower.

The second group includes cranes with a highly manouevrable boom. In cranes of this group (Fig.4b) all mechanisms and the counterweight are mounted at the bottom, on the turntable which revolves with the tower.

VIII. Complete the sentences using variants (a), (b) or (c).

1. Tower cranes are used for

1. assembling machines

2. loading and unloading operations

3. auxiliary construction purposes

2. The support carries

1. slewing mechanisms

2. hoisting mechanisms

3. traveling mechanisms

3. The rigid support is made in the form of

1. a latticed framework

2. a gantry

3. a pipe

4. The tower is made of

1. small-size metal tubes

2. steel tubes

3. large-diameter steel tubes

5. For the transportation the crane with the counterweight at the top is

1. folded down

2. split into separate units

3. assembled again