Several industrial and commercial buildings could reach 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 that have their own vehicle connected or other types which are operated from the rear of trucks. Tower cranes are the largest kinds on the market.
Tower cranes are the stand-alone structures which are usually found on high-rise building projects. Normally, they are part of a major city's downtown skyline. Wherever new construction such as skyscrapers or apartment buildings and commercial facilities like for example shopping center are being constructed, odds are a crane will be on site.
Types
The two key types of cranes can be differentiated by the way in which their jib or boom lifts materials. 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 type of tower crane, the jib can ratchet to downward or upward angles. The lifting capacity for both kinds can range from 30 pounds to 10,000 lbs.
Body
The crane's body is composed of a vertical steel mast which is composed of separate sections. The sections are added to be able increase the overall height of the machine. 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 driver of the crane works from inside of the tower.
Lift
The crane uses a braided metal cord to raise supplies. This cord extends out from a motor situated near the control module to the end of the jib or boom. There is a pulley system located 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 materials.