Some commercial and industrial buildings could reach heights of more than 60 stories. Obviously, when these buildings are being built, they require equally tall cranes to be able to move the materials to the higher floors. There are cranes which have their own vehicle connected or other kinds that are operated from the rear of trucks. Tower cranes are the biggest kinds offered on the market.
Tower cranes are stand-alone structures found as part of a major city's downtown skyline on high-rise building projects. When new construction like for instance skyscrapers or apartment buildings and commercial facilities such as shopping center are being constructed, chances are a crane will be on site.
Kinds
There are two different kinds of cranes: jib crane of the boom crane. The jib is a metal frame which extends from the main section. On a flat tower crane, the jib remains horizontal as it lifts things. On a luffing kind of tower crane, the jib can ratchet to upward or downward angles. The lifting capacity for both types could vary from 30 pounds to 10,000 pounds
Body
The body of the crane is composed of a mast. This is a vertical steel frame that is a combination of separate parts. In order to increase the overall height of the equipment, parts are added. The mast extends upward to where the desired height is, to the control module, that is a small room that has glass windows on all four sides or to the tower as it is also called. The crane driver works from inside of the tower.
Lift
To raise supplies, the crane uses a braided metal cord. The cord extends all the way to the end of the jib or boom from a motor located near 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 has weights. These weights help to prevent the crane from tipping over when lifting heavy materials.