Some commercial and industrial buildings could reach heights of over 60 stories. Apparently, while these buildings are being constructed, they require equally tall cranes to be able to transport the materials to the upper floors. There are cranes that are operated from the back of trucks or other types that have their own vehicle connected. Tower cranes are the biggest ones 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 such as apartment buildings and skyscrapers and commercial facilities like shopping center are being constructed, chances are a crane would be on site.
Types
There are two different types of cranes: boom crane or the jib crane. The jib is a metal frame that extends from the main section. On a flat tower crane, the jib remains horizontal when it carries items. On a luffing kind of tower crane, the jib could ratchet to downward or upward angles. The lifting capacity for both types could range from 30,000 lbs. 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 sections. In order to increase the overall height of the machinery, parts are added. The mast extends upward to where 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 crane driver works from inside of the tower.
Lift
The crane utilizes a braided metal cord to lift materials. This cord extends out from a motor located near the control module to the end of the boom or jib. 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.