Some commercial and industrial buildings are capable of reaching heights of more than 60 stories. Obviously, while these buildings are being constructed, they need equally tall cranes to be able to move the materials to the higher floors. There are cranes that have their own vehicle attached or other kinds which are operated from the back of trucks. Tower cranes are the biggest types on the market.
Tower cranes are stand-alone structures found as part of a major city's downtown skyline on high-rise building projects. When new construction like skyscrapers or apartment buildings and commercial facilities like for example shopping center are being constructed, odds are a crane would be on site.
Types
The two key types of cranes could be differentiated by the way in which their jib or boom raises supplies. The jib is the metal frame which extends from the main section. On a flat tower crane, the jib remains horizontal as it lifts items. On a luffing type of tower crane, the jib could ratchet to upward or downward angles. The lifting capacity for both types can range from 30 pounds 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 sections. In order to increase the overall height of the equipment, sections 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 driver of the crane works from inside of the tower.
Lift
The crane uses a braided metal cord to be able to lift supplies. This cord extends out from a motor situated next to 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 that 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 raising heavy materials.