Part III. Jib cranes
Text 10*. MOBILE CRANES
Mobile cranes have a wide range of uses in different branches of industry. Cranes of this type usually consist of a frame carrying a jib, a winch, and other necessary hoisting and controlling equipment. The frame is mounted on a cast-iron bed plate fitted with road wheels of the pneumatic type. One may also have them mounted on a caterpillar track or on a lorry chassis.
Lifting capacities of these light portable cranes of remarkable mobility range from 1 to 100 tons.
Mobile cranes are usually self-contained. They have a separate motor for each motion: hoisting, derricking and slewing. Thus any of all the motions can be operated at the same time. The speed of these motions is determined by the position of the accelerator pedal in the driver's cab. Alternatively the driver may sit on the revolving superstructure where he has a better view of the load on the hook. The full load may be carried either on the crane hook or on the truck platform.
Text 11.
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Text 11. DIESEL / HYDRAULIC CRANE LIFTS A TONNE
Recently (недавно) launched (появиться, начать выпуск) is the JC20 diese1/hydraulic mobile jib crane with a maximum capacity of I tonne at 2.25 radius, and 200 kg at maximum radius 6.40 m. The JC20 is capable of travelling with its full load on the hook.
This crane is hydraulically powered. Having good manoeuvrability combined with unrestricted (неограниченный) 360 deg slew, the crane is suitable for many applications including warehouses (склад). (From Materials Handling News)
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Text 12. ROUGH TERRAIN TELESCOPIC CRANE
Maximum lift capacity of this new model is 27 short tons (короткая/малая тонна = 902,2 кг) or 24 metric tons, and maximum load moment of 88 tonne.m. is reached at a reach (вынос стрелы) of 5 m over 360 deg. The crane weighs 22 tons fully operational.
The boom, which telescopes (выдвигать/ся) under load is 8.2 m retracted (втягивать/ся) and 19.2 or 24.7 m extended (вытягиваться). Maximum hook height is 26 m, or using a 4,2 m extension 29.5 m. Maximum travel speed is 44 km/hr, and turning radius 4.4 m.
Text 13.
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Text 13. ELEVATING СКАNЕ CABS
Most useful for quayside (пристань, причал) work is the Jones 571 EC (elevated (поднимать) cab) mobile crane which allows the driver to position his cab at any height between 3.96 and 6.85 m. Capacity of the crane is 32 tonnes at 10 ft radius. The cab is slightly (немного) larger than the standard model, giving more driver comfort.
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Text 14. CRANE'S JIB CAN BE HYDRAULICALLY FOLDED
New on the market (рынок) is the 10 ton capacity pneumatic-tyred mobile crane with a lattice jib of up to I9m that can be hydraulically (при помощи гидроцилиндра) folded without disassembly (демонтаж).
While travelling (В транспортном положении) the crane’s overall height is only 3.95 m and the overhang (выступающая, свешивающаяся часть) is exceptionally short. Fly jibs (дополнительные вставки) of 4, 6, or m can be fitted to a 13 m main jib, and can also be folded into travelling position without disassembly. (From Materials Handling Hews)