There are some industrial and commercial buildings that now surpass 60 stories or more. These buildings all need tall cranes to help move the supplies to the higher floors. There are cranes which have their own vehicle attached or other kinds that are operated from the back of trucks. Tower cranes are the largest kinds available on the market.
Tower cranes are the stand-alone structures which are normally found on high-rise building projects. Normally, they are part of a major city's downtown skyline. Wherever new construction like for instance 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 kinds of cranes can be distinguished by the way 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 when it lifts things. On a luffing type of tower crane, the jib could ratchet to downward or upward angles. The lifting capacity for both types can vary from 30,000 lbs. to 10,000 pounds
Body
The body of the crane is composed of a mast. This is a vertical steel frame which is a combination of separate parts. In order to increase the overall height of the equipment, sections are added. The mast extends upward to where the desired height is, to the control module, that is a small room which 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
The crane utilizes a braided metal cord to raise supplies. This cord extends out from a motor situated next to the control module to the end of the boom or jib. 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 holds weights. These weights help to prevent the crane from toppling over when heavy supplies are carried.