TOWER CRANE by noidarocker


									   TOWER CRANE
• A crane is a tower equipped with cables and pulleys
  that is used to lift and lower materials.
• Cranes are commonly used in the construction
  industry and in manufacturing heavy equipment.
• Construction cranes are usually temporary
  structures, either fixed to the ground or mounted on a
  purpose-built vehicle.
• Cranes may either be controlled from an operator in a
  cab that travels with the crane, by a pushbutton
  pendant control station, or by infrared or radio
  control. Where a cab operator is employed, workers
  on the ground will communicate with the operator
  through a system of standardised hand-signals or, in
  larger installations, radio systems; an experienced
  crew can position loads with great precision using
  only these signals. The largest revolving cranes in the
  world can be found on crane .
•   Ancient cranes
•   Medieval cranes
•   Railroad cranes
•   Mobile crane
•   Telescopic crane
•   Tower crane
•   Truck-mounted crane
•   Rough terrain crane
•   Crawler crane
•   Loader crane
•   Gantry crane
•   Overhead crane
•   Stacker crane
•   Floating crane
•   Aerial crane
                     TOWER CRANE
• The tower crane is a modern form of balance crane.
  Fixed to the ground, tower cranes often give the best
  combination of height and lifting capacity and are used
  in the construction of tall buildings.
• To save space and to provide stability the vertical part
  of the crane is often braced onto the completed
  structure which is normally the concrete lift shaft in the
  centre of the building.
• A horizontal boom is balanced asymmetrically across
  the top of the tower. Its short arm carries a
  counterweight of concrete blocks, and its long arm
  carries the lifting gear.
                         TOWER CRANE
• The crane operator sits in a cabin at the top of the tower. The
  operator's cabin is located at the top of the tower just below the
  horizontal boom. The boom is mounted on a slewing bearing and is
  rotated by means of a slewing motor. The lifting hook is operated by
  a system of pulleys.
• A tower crane is usually assembled by a telescopic crane of smaller
  lifting capacity but greater height, and in the case of tower cranes
  that have risen while constructing very tall skyscrapers, a smaller
  crane will sometimes be lifted to the roof of the completed tower to
  dismantle the tower crane afterward. A self-assembling tower crane
  has been demonstrated, which lifts itself off the ground using jacks,
  allowing the next section of the tower to be inserted at ground level.
                         TOWER CRANE
• There are two major considerations that are taken into account in
  the design of cranes.
• The first is that the crane must be able to lift a load of a specified
  weight and the
• second is that the crane must remain stable and not topple over
  when the load is lifted and moved to another location.
• The lifting capacity and the stability of crane are also equally
Cranes helping to
construct a tower block in
Melbourne, Australia

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