An overhead crane, commonly called a bridge crane, is a type of crane found in industrial environments. An overhead crane consists of two parallel rails seated on longitudinal I-beams attached to opposite steel columns by means of brackets. The traveling bridge spans the gap. A hoist, the lifting component of a crane, travels along the bridge. If the bridge is rigidly supported on two or more legs running on two fixed rails at ground level, the crane is called a gantry crane or a goliath crane.
An overhead crane, featuring runways, bridge, and hoist in a traditional industrial environment.
Overhead crane at the Skanska precast concrete factory in Hjärup, Sweden.
Gantry-style overhead cranes of the Hainaut quarry in Soignies, Belgium.
A woman operating a 20-ton[which?] EOT crane, 1914
A crane is a machine used to move materials both vertically and horizontally, utilizing a system of a boom, hoist, wire ropes or chains, and sheaves for lifting and relocating heavy objects within the swing of its boom. The device uses one or more simple machines, such as the lever and pulley, to create mechanical advantage to do its work. 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.
Manual crane from the late 19th century used for unloading small loads from ships at the Port of Barcelona, Spain
Reconstruction of a 10.4 m high Roman Polyspastos powered by a treadwheel at Bonn, Germany
Medieval (15th century) port crane for mounting masts and lifting cargo in Gdańsk
Double treadwheel crane in Pieter Bruegel's The Tower of Babel