Some commercial and industrial buildings could reach heights of over 60 stories. Apparently, while these buildings are being built, they need equally tall cranes to transport the supplies to the upper floors. There are cranes that have their own vehicle attached or other types which are operated from the back of trucks. Tower cranes are the largest types 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 like for example shopping center are being constructed, odds are a crane would be on site.
The two key kinds of cranes could be differentiated 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 type of tower crane, the jib can ratchet to downward or upward angles. The lifting capacity for both kinds could vary from 30 pounds to 10,000 lbs.
The crane's body is composed of a mast. This is a vertical steel frame that is a combination of individual sections. In order to increase the overall height of the equipment, sections are added. 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 called. The operator of the crane works from inside of the tower.
In order to lift materials, the crane utilizes a braided metal cord. The cord extends all the way to the end of the jib or boom 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 that 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 heavy materials are lifted.