Crane is device that lift and lower objects as well as move them horizontally

Crane

A Crane is a particular kind of device that can be used to lift and lower objects as well as move them horizontally. It is often furnished with a hoist rope, wire ropes or chains, and sheaves. The majority of its applications involve lifting and moving big objects. To generate mechanical advantage and move weights faster than a human could, the device makes use of one or more simple machines. Lifting machine are frequently used in manufacturing to assemble heavy equipment, in construction to move materials, and in transportation to load and unload freight.

The shadouf, a water-lifting mechanism created in prehistoric Mesopotamia (now Iraq) and later used in ancient Egyptian technology, is the first known example of a Crane machine. Construction lifting machine first existed in ancient Greece, where they were used to erect structures and were propelled by either people or animals (such as donkeys). Later, under the Roman Empire, larger lifting machine were created that could raise greater loads by using human treadwheels. Harbour lifting machine were first used in the High Middle Ages to load and unload ships as well as help with their construction; some were even incorporated into stone towers for added stability and strength. The oldest lifting machine were made of wood, but with the advent of the Industrial Revolution, cast iron, iron, and steel took over.

Lifting machine come in a wide variety of designs, each suited for a particular use. Jib lifting machine are the smallest and are used in workshops. Tower lifting machine are the largest and are used to erect towering buildings. Mini-cranes are also utilised for erecting high buildings, to facilitate constructions by reaching restricted locations. Construction of oil rigs and shipwreck recovery typically involve the use of large floating cranes. Although some lifting devices, such stacker Crane Market and loader lifting machine, may not precisely fulfil the definition of a lifting machine given above, they are nonetheless commonly referred to as lifting machine. A treadway wide enough for two employees to walk side by side made up the mediaeval treadwheel, which was a sizable wooden wheel rotating around a central shaft. The more sophisticated "clasp-arm" wheel type featured arms arranged as chords to the wheel rim, offering the possibility of employing a thinner shaft and thus providing a higher mechanical advantage. In contrast to the older "compass-arm" wheel, which had spokes directly driven into the central shaft.