Several industrial and commercial buildings can reach heights of more than 60 stories. Apparently, while these buildings are being constructed, they need equally tall cranes to be able to move the supplies to the upper floors. There are cranes that have their own vehicle attached or other types that are operated from the rear of trucks. Tower cranes are the largest kinds on the market.
Tower cranes are stand-alone structures found as part of a major city's downtown skyline on high-rise building projects. Wherever new construction like for example skyscrapers or apartment buildings and commercial facilities such as shopping center are being constructed, odds are a crane will be on site.
Types
There are two different types of cranes: boom crane or the jib crane. The jib is a metal frame which extends from the main section. On a flat tower crane, the jib remains horizontal when it carries things. On a luffing type 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 body of the crane is composed of a vertical steel mast that is composed of separate [parts. The sections are added to increase the overall height of the machinery. The mast extends upward to wherever the desired height is, to the control module, which is a small room that has glass windows on all four sides or to the tower as it is also referred to. The driver of the crane works from inside of the tower.
Lift
In order to raise supplies, the crane uses a braided metal cord. The cord extends all the way to the end of the boom or jib from a motor situated 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 which holds the cord becomes balanced by a counter jib located on the opposite side of the tower. The counter jib holds weights. These weights help to prevent the crane from toppling over when heavy supplies are lifted.