There are several industrial and commercial buildings that now exceed 60 stories or more. These buildings all require tall cranes to be able to help transport the materials to the higher floors. There are cranes which are operated from the back of trucks or other types that have their own vehicle connected. Tower cranes are the biggest kinds on the market.
Tower cranes are the stand-alone structures that are usually seen on high-rise building projects. Often, they are part of a major city's downtown skyline. When new construction such as apartment buildings and skyscrapers and commercial facilities like for instance shopping center are being built, odds are a crane would be on site.
Kinds
There are two different kinds of cranes: jib crane of the boom 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 type of tower crane, the jib could ratchet to upward or downward angles. The lifting capacity for both kinds can range from 30 pounds to 10,000 pounds
Body
The crane's body is composed of a vertical steel mast that is composed of separate [parts. The sections are added to be able 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
To lift supplies, 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 situated 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 has weights. These weights help to prevent the crane from tipping over when heavy supplies are carried.