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 supplies to the higher floors. There are cranes which are operated from the rear of trucks or other kinds which have their own vehicle connected. Tower cranes are the biggest types on the market.
Tower cranes are the stand-alone structures that are usually found on high-rise building projects. Usually, they are part of a major city's downtown skyline. When new construction like apartment buildings and skyscrapers and commercial facilities like shopping center are being built, odds are a crane would be on site.
Types
The two major kinds of cranes can be differentiated by the manner in which their boom or jib lifts supplies. The jib is the metal frame that extends from the main section. On a flat tower crane, the jib remains horizontal as it carries items. On a luffing kind of tower crane, the jib can ratchet to upward or downward angles. The lifting capacity for both types can vary from 30 pounds to 10,000 pounds
Body
The crane's body is composed of a mast. This is a vertical steel frame which is a combination of individual parts. In order to increase the overall height of the equipment, parts are added. The mast extends upward to wherever 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 referred to. The operator of the crane works from inside of the tower.
Lift
In order to lift supplies, the crane utilizes a braided metal cord. The cord extends all the way to the end of the boom or jib from a motor situated 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 located on the opposite side of the tower. The counter jib has weights. These weights help to prevent the crane from toppling over when raising heavy supplies.