In the early days the need for taller buildings became a need as the demand for manufactured products grew.
To build these taller buildings contractors needed to move construction materials easier and to higher floors on these buildings, the construction crane evolved.
The basic use of a crane is to lift a load, swing the load to a prepared location, then lower the load. This is the basic use of any crane, the reason for this need, man alone cannot lift the heavy loads or swing the load to the higher location, lower the load, when the construction contractors need to lift the heavier loads of materials to these taller building floors a crane is generally used.
The crane is used for many other types of construction projects such as bridge building, factory construction and other projects.
The crane generally has a cable that is rolled around a drum fastened to a fixed point on a platform.
The early crane generally had a lattice type boom with a pulley or sheave at the top portion of the boom, the cable ran over the pulley sheave at the top of the boom and down to a hook mounted at the cable end.
To increase the lifting capacity place a double pulley sheave at the top of the boom and a single sheave at the hook end of the cable. The more times the cable is run around a pulley sheave at the top of the boom and around a pulley sheave at the hook end, the lifting capacity is increased, this also means that the design of the crane has to be built to meet the lifting capacity.
Today there are many different types of cranes manufactured for many types of construction needs—truck mounted cranes—crawler cranes—rough terrain cranes—tower cranes—all terrain cranes—telescopic hydraulic cranes—many cranes today are hydraulic—cables are still needed.
The crane works on the same principle as when it was first invented.
Safety is always important when working around any lifting equipment, call your local dealer or go to the Web for info on crane safety.
For more information go to www excavating info.com