Башенные краны используются для подъема материалов, которые должны быть применены в строительстве.
В предложениях типа «Blinov was the first to design a track-laying tractor», инфинитив стоит в активном залоге и переводится с союзом «кто».
Блинов был первый, кто сконструировал гусеничный трактор.
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.
Й
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
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
assembling machines
loading and unloading operations
auxiliary construction purposes
2. The support carries
slewing mechanisms
hoisting mechanisms
traveling mechanisms
3. The rigid support is made in the form of
a latticed framework
a gantry
a pipe
4. The tower is made of
small-size metal tubes
steel tubes
large-diameter steel tubes
5. For the transportation the crane with the counterweight at the top is
folded down
split into separate units
assembled again
1. The stationary tower is a a) and then assembled again at a new site
metal framework
2. The first group includes cranes b) which revolves with the tower
with the revolving head and the
counterweight
3. All mechanisms of the crane c) which consists of several sections
are mounted on the turntable
4. For the transportation the crane d) which are mounted at the top
is split into separate large units
1. It is interesting to note that the turntable of the crane may revolve with the tower.
2. The counterweight is mounted to compensate for the weight of the boom and part of the load being lifted by the crane.
3. Tower cranes are used not only to lift materials but also to install separate elements.
4. The rotating upper frame of the crane is used to carry the power plant and operating machinery.
5. The body is designed not only to contain and protect the engine and other car components but it also protects people riding in the car.
1.Tower cranes … for loading and unloading operations.
2. Tower cranes … parts of the building and whole structures.
3. Tower cranes … separate elements.
4. A tower crane … of a support, a tower, a revolving structure, a counterweight, a boom and controls.
5. The support … the traveling mechanisms.
6. The tower … the operator`s cab.
7. The tower … as a lattices steel framework.
1. The rigid support is made … the form … a gantry … traveling wheels.
2. The operator`s cab is built … the middle … the tower.
3. …the transportation the crane is split … separate large units.
4. The crane split … separate units is then assembled … a new site.
5. The counterweight is mounted to compensate … the weight … the boom and part … the weight … the load.
5. The counterweight may be mounted … the top or … the bottom.
6. The load is lifted … the crane.
7. Cranes are classified … two main groups … the design … the tower.
Models: 1. What does a tower crane consist of ?
the operating equipment
the stationary tower
tractors
automobiles
tractors
winches
jacks
1.What cranes are extensively used in construction ?
2. What are tower cranes used for ?
3. How are tower cranes classified ?
4. What is the load moment ?
5. What does a tower crane consist of ?
6. What does the operating equipment consist of ?
7. Into how many groups are cranes classified according to the design of the tower?
8. What cranes does the first group include ?
9. What cranes does the second group include ?
| Обеспечение безопасности людей в чрезвычайных ситуациях |