Crane (machine)

A tower crane with a pivoted main boom

A crane is a lifting machine that has hoists, wire ropes and sheaves on it. It can be used both to raise and lower things or to move them left and right. Cranes are often used in the construction industry (building houses or buildings) and in creating or moving heavy things.

Crane (machine) Media

(Portuguese): Grua mecânica (Spanish): Grúa mecanica *(English): Crawler type derrick crane. Red - Hoist ropes; Green - Auxiliary hoist ropes; Blue - boom hoist and grab ropes
Manual crane from the late 19th century used for unloading small loads from ships at the Port of Barcelona, Spain
Greco-Roman Trispastos ("Three-pulley-crane"), a simple crane type (150 kg load)
Greco-Roman Pentaspastos ("Five-pulley-crane"), a medium-sized variant (c. 450 kg load)
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
Single treadwheel crane working from top of the building
Tower crane at the inland harbour of Trier from 1413
A crane constructed in 1742, used for mounting masts to large sailing vessels. Copenhagen, Denmark
A tower crane can "swing" its boom left and right, "dolly" its car (or traveler) in and out, and lift and lower its load
A tower crane rotates on its axis before lowering the lifting hook.