Several industrial and commercial buildings are capable of reaching heights of over 60 stories. Apparently, while these buildings are being constructed, they need equally tall cranes to be able to transport the supplies to the upper floors. There are cranes which are operated from the rear of trucks or other kinds that have their own vehicle connected. Tower cranes are the largest ones on the market.
Tower cranes are the stand-alone structures that are normally seen on high-rise building projects. Often, they are part of a major city's downtown skyline. Wherever new construction such as skyscrapers or apartment buildings and commercial facilities such as shopping center are being built, odds are a crane will be on site.
Kinds
The two key kinds of cranes can be differentiated by the manner in which their jib or boom raises materials. The jib is the metal frame that extends from the main section. On a flat tower crane, the jib remains horizontal when it carries things. On a luffing type of tower crane, the jib can ratchet to upward or downward angles. The lifting capacity for both kinds could range from 30 pounds to 10,000 pounds
Body
The crane's body is composed of a vertical steel mast which is composed of individual [parts. The parts 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, which is a small room that has glass windows on all four sides or to the tower as it is also called. The operator of the crane works from inside of the tower.
Lift
To lift supplies, the crane uses a braided metal cord. The cord extends all the way to the end of the boom or jib 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 that 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 toppling over when raising heavy supplies.