Several industrial and commercial buildings are capable of reaching heights of more than 60 stories. Obviously, while these buildings are being built, they need equally tall cranes to be able to transport the supplies to the higher floors. There are cranes which have their own vehicle connected or other kinds that are operated from the back of trucks. Tower cranes are the biggest types available on the market.
Tower cranes are stand-alone structures seen as part of a major city's downtown skyline on high-rise building projects. Wherever new construction like for instance skyscrapers or apartment buildings and commercial facilities like for example shopping center are being built, odds are a crane would be on site.
Kinds
The two major kinds of cranes could be differentiated by the way in which their jib or boom lifts materials. The jib is the metal frame that extends from the main section. On a flat tower crane, the jib remains horizontal as it carries things. On a luffing kind of tower crane, the jib can ratchet to downward or upward angles. The lifting capacity for both types could range from 30 pounds to 10,000 pounds
Body
The crane's body is composed of a mast. This is a vertical steel frame which is a combination of separate parts. In order to increase the overall height of the machine, sections are added. The mast extends upward to wherever the desired height is, to the control module, that is a small room which has glass windows on all four sides or to the tower as it is also referred to. The operator of the crane works from inside of the tower.
Lift
In order to raise materials, the crane uses a braided metal cord. The cord extends all the way to the end of the boom or jib from a motor located next to the control module. There is a pulley system located at the end of the jib, through which the cord is positioned and lowered down. The jib that holds the cord becomes balanced by a counter jib situated on the opposite side of the tower. The counter jib has weights. These weights help to prevent the crane from toppling over when heavy materials are lifted.