Several industrial and commercial buildings can reach heights of more than 60 stories. Obviously, when these buildings are being built, they need equally tall cranes to be able to transport the materials to the higher floors. There are cranes which have their own vehicle connected or other kinds that are operated from the back of trucks. Tower cranes are the biggest ones offered on the market.
Tower cranes are stand-alone structures seen as part of a major city's downtown skyline on high-rise building projects. Wherever new construction like for instance skyscrapers or apartment buildings and commercial facilities such as shopping center are being constructed, odds are a crane will be on site.
Types
There are two different kinds of cranes: boom crane or the jib crane. The jib is a metal frame that extends from the main section. On a flat tower crane, the jib remains horizontal as it carries things. On a luffing type of tower crane, the jib can ratchet to downward or upward angles. The lifting capacity for both types could vary from 30,000 lbs. to 10,000 pounds
Body
The crane's body is composed of a vertical steel mast that is composed of individual [parts. The sections are added to be able increase the overall height of the equipment. 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 operator works from inside of the tower.
Lift
In order to raise materials, the crane uses a braided metal cord. The cord extends all the way to the end of the jib or boom from a motor located near 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 situated on the tower's opposite side. The counter jib holds weights. These weights help to prevent the crane from toppling over when heavy materials are lifted.