17. Read the text. Find words and word combinations describing all kinds of cranes Cranes

(1) The function of a crane is to hoist or lower a load suspended from its jib. Various types of cranes are available, the type and size best suited for a specific operation being influenced by the following factors: 1. The nature of the work on which it is to operate. 2. The weight of load it has to handle.

(2) Mobile Cranes. Mobile cranes have a wide range of uses on building and civil engineering works of construction. Cranes of this type usually take the form of a frame carrying a jib, a winch, and other necessary hoisting and controlling equipment, the whole being mounted on a cast-iron bed plate fitted with road wheels of the pneumatic type. One may also have them mounted on caterpillar tracks or on a lorry chassis if desired.

(3) Tower Cranes. Tower cranes are of predominant use in construction' practice. They are employed for lifting mate­rials, parts and whole structures onto the buildings being erected, for the installation of separate elements and for load­ing and unloading operations.

(4) A tower crane consists essentially of a support, a tow­er, a revolving structure, a boom, a counterweight, and controls.

(5) The operating members consist of the boom, a hoisting pulley and a load handling attachment, usually a hook. The counterweight compensates for the weight of the boom and part of the weight of the load being lifted by the crane.

(6) As to the design, the tower cranes are subdivided into two main groups. The first group includes cranes with the turntable and the counterweight mounted at the top of the stationary tower. Some cranes of this type have a trolley travelling along the boom which makes it much easier to set structural elements precisely in the required place.

(7) The Climbing Crane. The climbing crane has been de­veloped to meet the demands for a crane capable of working on buildings taller than can be accommodated by rail-mounted tower cranes. It is also intended for use where restricted site conditions make track laying and consequently the use of a rail-mounted tower crane impracticable. Principal advantages of this crane are:

(8) 1) Lightness and ease of operation. 2) No real limitation to the height of the building upon which it can work. It can be used on buildings up to approximately 420 ft. high. 3) The crane climbs as the construction work progresses. 4) It can be employed on the site from the beginning of the construction, since with a suitable foundation block it will stand and work until the building progresses far enough for the crane to stand on the first floor. All the operations including the erection and climbing and dismantling are power-driven.

Tasks after reading:

18. Compose pairs of Russian and English terms. Make your own sentences on the topic of the text

подъемно-контрольное оборудование грузовое шасси установка отдельных элементов каркас, несущий нагрузку стрелы крана погрузочные и разгрузочные операции подъемный ролик установленный на верху стационарного крана приспособление для подвешивания груза груз, подвешенный к стреле крана вращающееся сооружение установленный на чугунной плоской платформе механизированные монтаж, подъем грузов демонтаж оборудованный дорожными колесами пневматического типа преобладающее использование тележка крана, двигающаяся вдоль стрелы крана башенные краны, установленные на рельсы соответствовать требованиям, предъявляемым к кранам гусеничные треки большое разнообразие в использовании

a load suspended from jib a wide range of uses a frame carrying a jib hoisting and controlling equipment mounted on a cast-iron bed plate fitted with road wheels of the pneumatic types caterpillar tracks lorry chassis predominant use installation of separate elements loading and unloading operations revolving structure hoisting pulley load handling attachment mounted at the top of the stationary crane trolley traveling along the boom to meet the demands for a crane rail-mounted tower cranes erection, climbing, dismantling to be power driven