In the High Middle Ages, harbour cranes were introduced to load and unload ships and assist with their construction-some were built into stone towers for extra strength and stability. Larger cranes were later developed in the Roman Empire, employing the use of human treadwheels, permitting the lifting of heavier weights. Construction cranes later appeared in ancient Greece, where they were powered by men or animals (such as donkeys), and used for the construction of buildings. The first known crane machine was the shaduf, a water-lifting device that was invented in ancient Mesopotamia (modern Iraq) and then appeared in ancient Egyptian technology. Cranes are commonly employed in transportation for the loading and unloading of freight, in construction for the movement of materials, and in manufacturing for the assembling of heavy equipment.
The device uses one or more simple machines to create mechanical advantage and thus move loads beyond the normal capability of a human.
It is mainly used for lifting heavy objects and transporting them to other places.
Manual crane from the late 19th century used for unloading small loads (bales, crates, etc.) from ships at the Port of Barcelona, Spain.Ī crane is a type of machine, generally equipped with a hoist rope, wire ropes or chains, and sheaves, that can be used both to lift and lower materials and to move them horizontally.
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