Several industrial and commercial buildings can reach heights of over 60 stories. Apparently, while these buildings are being constructed, they need equally tall cranes to be able to transport the supplies to the higher floors. There are cranes that have their own vehicle connected or other types which are operated from the rear of trucks. Tower cranes are the biggest ones offered 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 apartment buildings and skyscrapers and commercial facilities such as shopping center are being built, 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 kind of tower crane, the jib could ratchet to downward or upward angles. The lifting capacity for both kinds can range from 30 pounds to 10,000 lbs.
Body
The body of the crane is composed of a vertical steel mast that is composed of individual [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, that is a small room which has glass windows on all four sides or to the tower as it is also called. The driver of the crane works from inside of the tower.
Lift
In order to raise materials, the crane utilizes 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 situated 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 tower's opposite side. The counter jib holds weights. These weights help to prevent the crane from toppling over when heavy materials are lifted.