There are several industrial and commercial buildings which now surpass 60 stories or more. These buildings all require tall cranes to help transport the materials to the higher 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 on the market.
Tower cranes are the stand-alone structures which are usually found on high-rise building projects. Normally, they are part of a major city's downtown skyline. Wherever new construction like for example apartment buildings and skyscrapers and commercial facilities like for example shopping center are being built, odds are a crane would be on site.
Types
The two key kinds of cranes could be differentiated by the manner in which their boom or jib lifts materials. The jib is the metal frame that extends from the main section. On a flat tower crane, the jib remains horizontal when it lifts items. On a luffing kind of tower crane, the jib could ratchet to upward or downward angles. The lifting capacity for both kinds could range 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 machinery, sections are added. The mast extends upward to wherever the desired height is, to the control module, which is a small room which 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 uses a braided metal cord to lift materials. This cord extends out from a motor situated next to the control module to the end of the jib or boom. 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 tower's opposite side. The counter jib holds weights. These weights help to prevent the crane from toppling over when raising heavy materials.