Crane (lifting machine)
A crane is a machine for lifting and moving heavy loads. This article explains its components, history, common types, uses, and basic safety and operational considerations.
Overview
A crane is a mechanical device designed to lift, lower and horizontally move loads. Cranes provide mechanical advantage through combinations of levers, pulleys and powered winches to handle weights that would be impossible to move manually. They are fundamental to construction, shipping, manufacturing and other industries that require handling large or heavy items.
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Main components and how they work
Most cranes share a set of core components that enable lifting and movement. These include a lifting mechanism or hoist, cables or chains such as wire ropes, and guide wheels called sheaves. A structural framework supports the load and allows movement: booms, jibs, masts or girders depending on the crane type. Operators use controls to regulate speed and direction while load charts and rigging hardware determine safe lifting limits.
History and development
Simple cranes have existed since antiquity, evolving from human- and animal-powered winches and block-and-tackle arrangements. Over centuries the basic principles remained the same while materials, power sources and control systems advanced. The industrial era introduced steam and later internal combustion and electric power, enabling much larger and more reliable machines. Modern cranes add hydraulics, automated controls and safety systems to increase precision and reduce risk.
Common types and typical uses
- Tower cranes are common on urban construction sites for erecting tall buildings.
- Mobile cranes mount on wheeled or tracked vehicles and are prized for flexibility.
- Overhead and gantry cranes are widely used in factories and shipyards to move loads along fixed paths.
- Specialized cranes include floating, telescopic and railroad-mounted variants for specific environments.
Applications range from lifting building components, loading cargo and assembling heavy equipment to maintenance tasks such as positioning wind-turbine components.
Operation, safety and regulations
Safe crane operation relies on competent operators, proper rigging, routine inspection and adherence to load ratings. Before a lift, crews check conditions, secure the load and consult load charts. Regulatory frameworks and industry standards prescribe inspection intervals, certification requirements and safe practices. Remote and automated systems are increasingly used to improve safety and precision.
Notable distinctions and further reading
Cranes vary widely in capacity, mobility and intended environment; choosing the right type involves balancing reach, lift capacity and site constraints. For technical guidance on components and maintenance consult manufacturers and standards organizations, and for an introduction to terminology see resources about crane types and specifications. For operational tools and replacement parts, suppliers list detailed information about hoists, wire ropes and sheaves.
Crane types
There are different types and designs depending on the application.
- Overhead crane, mistakenly called indoor crane, overhead crane or suspension crane runway.
- Gantry crane built like a gate, rail runway / track runway built on the ground (corridor) or trackless gantry crane on wheels/crawler.
- Jib Crane
- Semi-gantry crane
- Loading bridge, crane bridge e.g. at the port
- Portal luffing jib crane
- Full gantry luffing slewing crane
- Derrick Crane
- Cable crane, cableway crane, slipway crane (shipyard, logging crane)
- Bracket crane
- Pillar-mounted slewing crane
- Jib crane
- Floating crane
- Aircraft hoist crane
- Stacking crane
- Tower crane also called tower crane, construction crane, top and bottom slewing crane
- rail-mounted mobile cranes
- Rail crane, slewing rail crane, overhead rail crane.
- Overhead Crane
- non-rail mobile cranes
- Truck crane, mobile crane
- all-terrain low-speed cranes (rough terrain cranes)
- All-Terrain Cranes
- Crawler crane
- Travellift (to lift ships out of the water and transport them to the shipyard)
- Ring crane (1 or 2 rail rings, each for 4 multi-wheeled trolleys, to transfer the load over a large area into the ground)
- Loading crane (for loading and unloading trucks and ships)
- Ship crane, shipboard crane
- stationary container crane as loading or unloading bridge for container ships
- Special cranes (loading bridges) for special cargoes such as grain and tropical fruit (bananas)
- Stationary, permanently installed cranes and lifts in multi-storey warehouses and construction sites. Electric drive, formerly drive via treadmill, göpel or similar.
- Large crane
Differentiation according to mast construction
- Telescopic crane
- Lattice boom crane
Mobile jib cranes are called mobile cranes.
Hans Liebherr designed the world's first mobile tower crane, the TK 8, in 1949, with initially moderate success.
Miscellaneous
Helicopters, cable cars, balloons and kites (ferries) can take over the function of a crane if necessary. However, their use is usually limited to impassable areas or for work on very high structures because of the high operating costs. Helicopter types specially designed for crane use are: K-Max, Sikorsky S-64 Skycrane, Mil Mi-10, and a trial balloon was CargoLifter CL75 AirCrane with 75 t payload in 2001/2001.
Functionally similar to the following tools: fishing rod, ship's hook, grappling aid, fire hook, hook bar to manipulate clothes on hangers on high bars or to tip small boxes down from high shelves.
30 cranes on 21 hectares moved in the dusk of 15 February 2014 as a ballet choreographed with light effects to the 15-minute symphony Kranensee, composed by Florian Reithner, on the large construction site of the Urban Lakeside Aspern being built in the northeast of Vienna. With this, the construction companies celebrated the first roof levels and 14,000 came to watch. Crane ballets were already performed in 1996 during the redesign of Potsdamer Platz Berlin and in 2010 as Requiem of the Cranes in HafenCity Hamburg.
The term crane ballet has been used in recent years as an embellishing description for the mere accumulation of cranes, for example on large construction sites.
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AlegsaOnline.com Crane (lifting machine) Leandro Alegsa
URL: https://en.alegsaonline.com/art/23954