There are some industrial and commercial buildings that now surpass 60 stories or more. These buildings all need tall cranes to help move the supplies to the upper floors. There are cranes which have their own vehicle attached or other kinds 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. Wherever new construction like for instance apartment buildings and skyscrapers and commercial facilities like shopping center are being built, odds are a crane would be on site.
Kinds
There are two different types of cranes: boom crane or the jib crane. The jib is a metal frame which extends from the main section. On a flat tower crane, the jib remains horizontal as it carries things. On a luffing kind of tower crane, the jib can ratchet to upward or downward angles. The lifting capacity for both kinds could range from 30,000 lbs. to 10,000 pounds
Body
The crane's body 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, parts 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 referred to. The crane driver works from inside of the tower.
Lift
The crane utilizes a braided metal cord to be able to raise materials. This cord extends out from a motor located near the control module to the end of the jib or boom. 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 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.