Several industrial and commercial buildings are capable of reaching heights of over 60 stories. Apparently, while these buildings are being built, they require equally tall cranes to be able to move the supplies to the higher floors. There are cranes that are operated from the rear of trucks or other types which have their own vehicle attached. Tower cranes are the biggest ones 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 such as apartment buildings and skyscrapers and commercial facilities like for instance shopping center are being built, chances are a crane would be on site.
Types
The two key kinds of cranes could be distinguished by the manner in which their boom or jib raises materials. The jib is the metal frame which extends from the main section. On a flat tower crane, the jib remains horizontal as it lifts items. On a luffing kind of tower crane, the jib can ratchet to downward or upward angles. The lifting capacity for both types can range from 30,000 lbs. to 10,000 lbs.
Body
The body of the crane is composed of a vertical steel mast which is composed of individual [parts. The sections are added to increase the overall height of the equipment. 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 operator works from inside of the tower.
Lift
The crane utilizes a braided metal cord to be able to raise supplies. This cord extends out from a motor situated next to the control module to the end of the boom or jib. 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 has weights. These weights help to prevent the crane from tipping over when lifting heavy materials.