Crane (machine)

{{Short description|Type of machine}} {{More citations needed|date=November 2011}} {{Use dmy dates|date=October 2020}} [[File:Crane machine slewing platform.svg|thumb|right|Diagram of a modern crawler crane with [[outrigger]]s. The [[lattice girder|latticed]] boom is fitted with a [[Jib (crane)|jib]].|363x363px]] [[File:3U2A6305.jpg|270px|thumb|Manual crane from the late 19th century used for unloading small loads from ships at the Port of Barcelona, Spain]] [[File:View in Cape Town CBD, from the Corner of Roeland Street.jpg|thumb|right|300px|Modern cranes used as part of the reconstruction of the [[Houses of Parliament, Cape Town|Houses of Parliament]], in [[Cape Town CBD]]]]

A '''crane''' is a [[machine]] used to move materials both vertically and horizontally, utilizing a system of a [[guyed mast|boom]], [[hoist (device)|hoist]], [[wire rope]]s or [[chain]]s, and [[Sheave (mechanical)|sheaves]] for lifting and relocating heavy objects within the swing of its boom. The device uses one or more [[simple machine]]s, such as the [[lever]] and [[pulley]], to create [[mechanical advantage]] to do its work.<ref>{{Cite encyclopedia |title=Simple machine |url=https://www.britannica.com/technology/simple-machine |archive-url=https://web.archive.org/web/20250906175840/https://www.britannica.com/technology/simple-machine |archive-date=2025-09-06 |access-date=2025-11-24 |encyclopedia=Encyclopedia Britannica |language=en}}</ref> 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 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]]. 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. Larger cranes were later developed in the [[Roman Empire]], employing the use of human [[treadwheel]]s, permitting the lifting of heavier weights. 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. The earliest cranes were constructed from wood, but [[cast iron]], [[iron]] and [[steel]] took over with the coming of the [[Industrial Revolution]].

For many centuries, power was supplied by the physical exertion of men or animals, although hoists in [[watermill]]s and [[windmill]]s could be driven by the harnessed natural power. The first ''mechanical'' power was provided by [[steam engine]]s, the earliest [[steam crane]] being introduced in the 18th or 19th century, with many remaining in use well into the late 20th century.<ref>{{cite web|url=https://brynthomascranes.com/cranes-guide/#how-are-cranes-powered |title=How Are Cranes Powered? |date=22 February 2017 |publisher=Bryn Thomas Cranes |access-date=2017-11-20}}</ref><ref>Encyclopædia Britannica. "Crane." Britannica.com. Accessed 19 November 2025.</ref> Modern cranes usually use [[internal combustion engine]]s or [[electric motor]]s and [[hydraulic]] systems to provide a much greater lifting capability than was previously possible, although manual cranes are still utilized where the provision of power would be uneconomic.

There are many different types of cranes, each tailored to a specific use.<ref>{{cite book|url=https://link.springer.com/book/10.1007/978-981-13-5770-1|title=Dynamics and Control of Industrial Cranes |series=Advances in Industrial Control |date=2019 |doi=10.1007/978-981-13-5770-1 |isbn=978-981-13-5769-5 }}</ref> Sizes range from the smallest jib cranes, used inside workshops, to the tallest tower cranes, used for constructing high buildings. Mini-cranes are also used for constructing high buildings, to facilitate constructions by reaching tight spaces. Large floating cranes are generally used to build [[Oil platform|oil rigs]] and salvage sunken ships.{{Citation needed|date=August 2016}}

Some lifting machines do not strictly fit the above definition of a crane, but are generally known as cranes, such as stacker cranes and loader cranes.

==Etymology== Cranes were so called from the resemblance to the long neck of the [[Crane (bird)|bird]], cf. <span title="geranòs">{{langx|grc|γερανός}}</span>, French ''grue''.{{sfn|Pitt|1911|p=368}}

==History==

===Ancient civilizations=== The earliest known lifting device was the ''[[shadoof]]'', a crane-like device used in [[Mesopotamia]] around 3000 BCE, which had a [[lever]] [[Mechanism_(engineering)|mechanism]] and was used for [[irrigation]] purposes.<ref name="Singer-1954">{{cite book |last1=Singer |first1=Charles |title=A History of Technology, Volume I: From Early Times to Fall of Ancient Empires |last2=Holmyard |first2=E.J. |last3=Hall |first3=A.R. |publisher=Oxford University Press |year=1954 |pages=691–695}}</ref><ref name="Paipetis">{{cite book |last1=Paipetis |first1=S. A. |title=The Genius of Archimedes -- 23 Centuries of Influence on Mathematics, Science and Engineering: Proceedings of an International Conference held at Syracuse, Italy, June 8–10, 2010 |last2=Ceccarelli |first2=Marco |date=2010 |publisher=[[Springer Science & Business Media]] |isbn=978-90-481-9091-1 |page=416}}</ref><ref name="Chondros">{{cite journal |last1=Chondros |first1=Thomas G. |date=1 November 2010 |title=Archimedes life works and machines |journal=Mechanism and Machine Theory |volume=45 |issue=11 |pages=1766–1775 |doi=10.1016/j.mechmachtheory.2010.05.009 |issn=0094-114X}}</ref><ref name="Sayed">{{cite thesis |last1=Sayed |first1=Osama Sayed Osman |title=The Structural Performance of Tower Cranes Using Computer Program SAP2000-v18 |date=19 October 2016 |access-date=1 August 2019 |publisher=[[Sudan University of Science and Technology]] |url=http://repository.sustech.edu/handle/123456789/15637 |archive-url=https://web.archive.org/web/20191214215707/http://repository.sustech.edu/handle/123456789/15637 |archive-date=14 December 2019 |quote=The earliest recorded version or concept of a crane was called a Shaduf and used over 4,000 years by the Egyptians to transport water. |last2=Attalemanan |first2=Abusamra Awad}}</ref> It was invented in [[Mesopotamia]] (modern Iraq) circa 3000 BC.<ref name="Paipetis" /><ref name="Chondros" /> The shadouf subsequently appeared in [[ancient Egyptian technology]] circa 2000 BC.<ref name="Sayed" /><ref>{{cite book |last1=Faiella |first1=Graham |title=The Technology of Mesopotamia |date=2006 |publisher=[[The Rosen Publishing Group]] |isbn=978-1-4042-0560-4 |page=27}}</ref> However, the transition to building cranes occurred in [[ancient Greece]] during the late 6th century BCE.<ref name="Coulton 1974, 7">{{harvnb|Coulton|1974|p=7}}</ref> [[Archaeological evidence]], including distinctive cuttings for lifting [[tongs]] and [[Lewis (lifting appliance)|Lewis irons]] on [[stone]] blocks of [[Greek temple]]s, indicates a fundamental shift in [[engineering]] strategy coinciding with the development of the [[Polis|Greek city-state]] (''polis'').<ref name="Lewis-1993">{{cite journal |last=Lewis |first=M.J.T. |year=1993 |title=The Introduction of the Crane to Greek Building Sites |journal=Journal of Hellenic Studies |volume=113 |pages=69–76 |doi=10.2307/632395 |jstor=632395}}</ref> Since these holes point at the use of a lifting device, and since they are to be found either above the center of gravity of the block, or in pairs equidistant from a point over the center of gravity, they are regarded by archaeologists as the positive evidence required for the existence of the crane.<ref name="Coulton 1974, 7" />

This labor constraint necessitated [[mechanical advantage]] provided by the [[winch]] and [[pulley]] system, replacing labor-intensive ramps. In contrast to the [[Archaic period in Greece|archaic period]] with its pattern of ever-increasing block sizes, Greek temples of the classical age like the [[Parthenon]] invariably featured stone blocks weighing less than 15–20 metric tons. Also, the practice of erecting large monolithic columns was practically abandoned in favour of using several column drums.<ref name="Coulton 1974, 14f.">{{harvnb|Coulton|1974|pp=14ff}}</ref>

Although the exact circumstances of the shift from the ramp to the crane technology remain unclear, it has been argued that the volatile social and political conditions of [[Greece]] were more suitable to the employment of small, professional construction teams than of large bodies of unskilled labour, making the crane preferable to the Greek [[polis]] over the more labour-intensive ramp which had been the norm in the autocratic societies of [[Ancient Egypt|Egypt]] or [[Assyria]].<ref name="Coulton 1974, 14f." />

The first unequivocal literary evidence for the existence of the compound pulley system appears in the ''Mechanical Problems'' (''Mech''. 18, 853a32–853b13) attributed to [[Aristotle]] (384–322 BC), but perhaps composed at a slightly later date. Around the same time, block sizes at Greek temples began to match their archaic predecessors again, indicating that the more sophisticated compound pulley must have found its way to Greek construction sites by then.<ref name="Coulton 1974, 16">{{harvnb|Coulton|1974|p=16}}</ref>

===Roman Empire=== {{See also|Treadwheel crane}} [[File:Trispastos scheme.svg|thumb|Greco-Roman ''[[Trispastos]]'' ("Three-pulley-crane"), a simple crane type (1800 N load)]] [[File:Pentaspastos scheme.svg|thumb|Greco-Roman ''Pentaspastos'' ("Five-pulley-crane"), a medium-sized variant (c. 6000 N load)]] [[File:Roemerkran.jpg|thumb|Reconstruction of a 10.4 m high Roman ''Polyspastos'' powered by a treadwheel at [[Bonn]], Germany]]

The heyday of the crane in ancient times came during the [[Roman Empire]], when construction activity soared and buildings reached enormous dimensions. The Romans adopted the Greek crane and developed it further. There is much available information about their lifting techniques, thanks to rather lengthy accounts by the engineers [[Vitruvius]]<ref>{{Cite web |title=PerseusCatalog |url=https://catalog.perseus.org/catalog/urn:cts:latinLit:phi1056.phi001 |access-date=2026-01-22 |website=catalog.perseus.org}}</ref> and [[Heron of Alexandria]]<ref>{{Cite journal |last=Papadopoulos |first=Evangelos |date=2007-01-01 |title=Heron of Alexandria (c. 10–85 AD) |url=https://www.academia.edu/2829688/Heron_of_Alexandria_c_10_85_AD_ |journal=History of Mechanism and Machine Science |pages=217–245 |doi=10.1007/978-1-4020-6366-4_9}}</ref>. There are also two surviving reliefs of Roman [[treadwheel crane]]s, with the [[Quintus Haterius|Haterii]] tombstone from the late first century AD being particularly detailed.

[[File:Tomb of the Haterii crane relief (Gusman Art decoratif I pl 27).jpg|thumb|right|Roman relief from the Tomb of the Haterii showing a construction crane with a pulley system]]

[[Roman engineering|Roman engineers]] advanced Greek designs by analyzing mechanical advantage ratios. The simplest Roman crane, the ''trispastos'', consisted of a double-beam jib, a [[winch]], a [[rope]], and a block containing three pulleys. Having thus a [[mechanical advantage]] of 3:1, it has been calculated that a single man working the winch could raise {{cvt|150|kg|lb}} (3 pulleys x {{cvt|50|kg|lb|disp=or}} = 150), assuming that {{cvt|50|kg|lb}} represent the maximum effort a man can exert over a longer time period. Heavier crane types featured five pulleys (''pentaspastos'') or, in case of the largest one, a set of three by five pulleys (''Polyspastos'') and came with two, three or four masts, depending on the maximum load<ref name="Humphrey-1998">{{cite book |last1=Humphrey |first1=John W. |title=Greek and Roman Technology: A Sourcebook |last2=Oleson |first2=John P. |last3=Sherwood |first3=Andrew N. |publisher=Routledge |year=1998 |isbn=978-0-415-06137-7 |pages=95–103}}</ref>.

The ''polyspastos'' represented a major leap in mechanical efficiency. When worked by four men at both sides of the winch, it could readily lift {{cvt|3,000|kg|lb}} (3 ropes x 5 pulleys x 4 men x {{cvt|50|kg|lb|disp=or}} = {{cvt|3,000|kg|lb|disp=or}}). If the winch was replaced by a treadwheel, the maximum load could be doubled to {{cvt|6,000|kg|lb}} at only half the crew, since the treadwheel possesses a much bigger mechanical advantage due to its larger diameter. This meant that, in comparison to the construction of the [[ancient Egypt]]ian [[Egyptian pyramids|pyramids]], where about 50 men were needed to move a 2.5 ton{{which|date=December 2021}} stone block up the ramp ({{cvt|50|kg|lb}} per person), the lifting capability of the Roman ''polyspastos'' proved to be ''60 times'' higher ({{cvt|3,000|kg|lb|disp=or}} per person).<ref>All data from: {{harvnb|Dienel|Meighörner|1997|p=13}}</ref> However, substituting the winch with a ''[[treadwheel]]''—a large wooden wheel rotated by men walking inside it—doubled this capacity to 6,000 kg with half the crew. This efficiency increase resulted from the treadwheel's larger [[diameter]] creating a much greater [[moment arm]] compared to a hand winch. This system increased lifting efficiency by 60 times compared to [[Egyptian pyramids|Egyptian pyramid]] construction, where approximately 50 men were required to move a 2.5-[[tonne]] stone block up a ramp.<ref name="Landels-1978">{{cite book |last=Landels |first=J.G. |title=Engineering in the Ancient World |publisher=University of California Press |year=1978 |isbn=978-0-520-03428-0 |pages=84–98}}</ref>

{| class="wikitable" |+ Roman crane mechanical advantage ! Crane type !! Pulleys !! Power source !! Capacity (kg) |- | Trispastos || 3 || 1 worker (winch) || 150 |- | Pentaspastos || 5 || — || 250 |- | Polyspastos || 15 (3×5) || 4 workers (winch) || 3,000 |- | Polyspastos || 15 (3×5) || 2 workers (treadwheel) || 6,000 |}

However, numerous extant Roman buildings which feature much heavier stone blocks than those handled by the ''polyspastos'' indicate that the overall lifting capability of the Romans went far beyond that of any single crane. At the temple of Jupiter at [[Baalbek]], for instance, the [[architrave]] blocks weigh up to 60 tons each, and one corner [[cornice]] block even over 100 tons, all of them raised to a height of about {{cvt|19|m|ft|1}}.<ref name="Coulton 1974, 16" /> In [[Rome]], the capital block of Trajan's Column weighs 53.3 tons, which had to be lifted to a height of about {{cvt|34|m|ft|1}} (see [[Trajan's Column#Construction|construction of Trajan's Column]]).<ref name="Lancaster 1999, 426">{{harvnb|Lancaster|1999|p=426}}</ref>

It is assumed that Roman engineers lifted these extraordinary weights by two measures (see picture below for comparable Renaissance technique): First, as suggested by Heron, a lifting tower was set up, whose four masts were arranged in the shape of a quadrangle with parallel sides, not unlike a [[siege tower]], but with the column in the middle of the structure (''Mechanica'' 3.5).<ref name="Lancaster 1999, 427ff.">{{harvnb|Lancaster|1999|pp=427ff}}</ref> Second, a multitude of [[Capstan (nautical)|capstans]] were placed on the ground around the tower, for, although having a lower leverage ratio than treadwheels, capstans could be set up in higher numbers and run by more men (and, moreover, by draught animals).<ref name="Lancaster 1999, 434ff.">{{harvnb|Lancaster|1999|pp=434ff}}</ref> This use of multiple capstans is also described by [[Ammianus Marcellinus]] (17.4.15) in connection with the lifting of the [[List of obelisks in Rome|Lateranense obelisk]] in the [[Circus Maximus]] (c. 357 AD). The maximum lifting capability of a single capstan can be established by the number of lewis iron holes bored into the monolith. In case of the Baalbek architrave blocks, which weigh between 55 and 60 tons, eight extant holes suggest an allowance of 7.5 ton per lewis iron, that is per capstan.<ref name="Lancaster 1999, 436">{{harvnb|Lancaster|1999|p=436}}</ref> Lifting such heavy weights in a concerted action required a great amount of coordination between the work groups applying the force to the capstans.

===Middle Ages===

==== Persian Innovations ==== [[File:Al-jazari_water_device.jpg|thumb|right|Diagram of a water-raising device from [[Al-Jazari]]'s ''Book of Knowledge of Ingenious Mechanical Devices'' (1206 CE)]]During the medieval period, Persian engineers advanced lifting technology significantly, bridging the gap between ancient mechanics and modern engineering. [[Al-Jazari]] (1136–1206), working in the [[Artuqids|Artuqid]] court, documented revolutionary [[Mechanism (engineering)|lifting mechanisms]] including early versions of the [[crankshaft]], [[camshaft]], and [[reciprocating pump]] in his ''Book of Knowledge of Ingenious Mechanical Devices'' (1206 CE). These innovations transformed water-lifting from manual systems to semi-automated mechanisms. Notable applications included the [[Damascus]] hydraulic systems, where [[Chain pump|saqiya chain pumps]] powered by [[hydropower]] supplied water to major institutions for centuries, introducing mechanical principles like the conversion of rotary motion to reciprocating motion that later became central to modern crane winches.<ref name="Hill-1974">{{cite book |last=Hill |first=Donald R. |title=The Book of Knowledge of Ingenious Mechanical Devices |publisher=Reidel |year=1974 |isbn=90-277-0329-9 |page=279}}</ref>

==== Reintroduction of Treadwheel Cranes in Europe ==== During the [[High Middle Ages]], the treadwheel crane was reintroduced on a large scale after the technology had fallen into disuse in western Europe with the demise of the [[Western Roman Empire]].<ref>{{harvnb|Matthies|1992|p=514}}</ref> The earliest reference to a treadwheel (''magna rota'') reappears in archival literature in France about 1225,<ref name="Andrea Matthies, p.515">{{harvnb|Matthies|1992|p=515}}</ref> followed by an illuminated depiction in a manuscript of probably also French origin dating to 1240.<ref>{{harvnb|Matthies|1992|p=526}}</ref> In navigation, the earliest uses of harbor cranes are documented for [[Utrecht (city)|Utrecht]] in 1244, [[Antwerp]] in 1263, [[Bruges]] in 1288 and [[Hamburg]] in 1291,<ref name="Matheus 1996, 345">{{harvnb|Matheus|1996|p=345}}</ref> while in England the treadwheel is not recorded before 1331.<ref name="Matthies 1992, 524">{{harvnb|Matthies|1992|p=524}}</ref>

[[File:Belgium-6311 - Treadmill Crane (13896807830).jpg|thumb|left|Interior of a medieval treadwheel crane in [[Bruges]], Belgium, showing the wooden wheel mechanism powered by human walking]]

[[File:Tretkran (Bruegel).jpg|thumb|Double treadwheel crane in Pieter Bruegel's ''[[The Tower of Babel (Bruegel)|The Tower of Babel]]'']] Generally, vertical transport could be done more safely and inexpensively by cranes than by customary methods. Typical areas of application were harbors, mines, and, in particular, building sites where the treadwheel crane played a pivotal role in the construction of the lofty [[Gothic architecture|Gothic cathedrals]].

Nevertheless, both archival and pictorial sources of the time suggest that newly introduced machines like treadwheels or [[wheelbarrow]]s did not completely replace more labor-intensive methods like [[ladder]]s, [[Brick hod|hods]] and [[handbarrow]]s. Rather, old and new machinery continued to coexist on medieval construction sites<ref>{{harvnb|Matthies|1992|p=545}}</ref> and harbors.<ref name="Matheus 1996, 345" />

Apart from treadwheels, medieval depictions also show cranes to be powered manually by windlasses with radiating [[spoke]]s, [[Crank (mechanism)|cranks]] and by the 15th century also by windlasses shaped like a [[ship's wheel]]. To smooth out irregularities of impulse and get over 'dead-spots' in the lifting process [[flywheel]]s are known to be in use as early as 1123.<ref>{{harvnb|Matthies|1992|p=518}}</ref> [[File:Gdansk_zuraw.jpg|right|thumb|The [[Gdańsk Crane]], a medieval [[treadwheel]] crane built in 1442–1444, one of the largest and best-preserved harbor cranes from the Middle Ages]] The exact process by which the treadwheel crane was reintroduced is not recorded,<ref name="Andrea Matthies, p.515" /> although its return to construction sites has undoubtedly to be viewed in close connection with the simultaneous rise of Gothic architecture. The reappearance of the treadwheel crane may have resulted from a technological development of the [[windlass]] from which the treadwheel structurally and mechanically evolved. Alternatively, the medieval treadwheel may represent a deliberate reinvention of its Roman counterpart drawn from [[Vitruvius]]' ''[[De architectura]]'' which was available in many monastic libraries. Its reintroduction may have been inspired, as well, by the observation of the labor-saving qualities of the [[Water wheel|waterwheel]] with which early treadwheels shared many structural similarities.<ref name="Matthies 1992, 524" />

====Structure and placement==== The medieval treadwheel was a large wooden wheel turning around a [[Axle|central shaft]] with a treadway wide enough for two workers walking side by side. While the earlier 'compass-arm' wheel had spokes directly driven into the central shaft, the more advanced "clasp-arm" type featured arms arranged as chords to the wheel rim,<ref>{{harvnb|Matthies|1992|pp=525ff}}</ref> giving the possibility of using a thinner shaft and providing thus a greater mechanical advantage.<ref>{{harvnb|Matthies|1992|p=536}}</ref>

[[File:Reconstruction of the temple of Jerusalem.jpg|thumb|left|Single treadwheel crane working from top of the building]] Contrary to a popularly held belief, cranes on medieval building sites were neither placed on the extremely lightweight [[scaffolding]] used at the time nor on the thin walls of the Gothic churches which were incapable of supporting the weight of both hoisting machine and load. Rather, cranes were placed in the initial stages of construction on the ground, often within the building. When a new floor was completed, and massive tie beams of the roof connected the walls, the crane was dismantled and reassembled on the roof beams from where it was moved from bay to bay during construction of the vaults.<ref name="Matthies 1992, 533">{{harvnb|Matthies|1992|p=533}}</ref> Thus, the crane "grew" and "wandered" with the building with the result that today all extant construction cranes in England are found in church towers above the vaulting and below the roof, where they remained after building construction for bringing material for repairs aloft.<ref>{{harvnb|Matthies|1992|pp=532ff}}</ref>

Less frequently, medieval illuminations also show cranes mounted on the outside of walls with the stand of the machine secured to [[putlog]]s.<ref>{{harvnb|Matthies|1992|p=535}}</ref>

====Mechanics and operation==== [[File:Trier Germany Alter Krahnen.jpg|thumb|right|Tower crane at the inland harbour of [[Trier]] from 1413]] In contrast to modern cranes, medieval cranes and hoists — much like their counterparts in Greece and Rome<ref name="Coulton 1974, 6">{{harvnb|Coulton|1974|p=6}}</ref> — were primarily capable of a vertical lift, and not used to move loads for a considerable distance horizontally as well.<ref name="Matthies 1992, 533" /> Accordingly, lifting work was organized at the workplace in a different way than today. In building construction, for example, it is assumed that the crane lifted the stone blocks either from the bottom directly into place,<ref name="Matthies 1992, 533" /> or from a place opposite the centre of the wall from where it could deliver the blocks for two teams working at each end of the wall.<ref name="Coulton 1974, 6" /> Additionally, the crane master who usually gave orders at the treadwheel workers from outside the crane was able to manipulate the movement laterally by a small rope attached to the load.<ref name="Dienel, Meighörner 1997, 17">{{harvnb|Dienel|Meighörner|1997|p=17}}</ref> Slewing cranes which allowed a rotation of the load and were thus particularly suited for dockside work appeared as early as 1340.<ref>{{harvnb|Matthies|1992|p=534}}</ref> While ashlar blocks were directly lifted by sling, lewis or devil's clamp (German ''Teufelskralle''), other objects were placed before in containers like [[pallet]]s, [[basket]]s, wooden boxes or [[barrel]]s.<ref>{{harvnb|Matthies|1992|p=531}}</ref>

It is noteworthy that medieval cranes rarely featured [[Ratchet (device)|ratchets]] or [[brake]]s to forestall the load from running backward.<ref>{{harvnb|Matthies|1992|p=540}}</ref> This curious absence is explained by the high [[Friction|friction force]] exercised by medieval tread-wheels which normally prevented the wheel from accelerating beyond control.<ref name="Dienel, Meighörner 1997, 17" />

====Harbour usage==== {{See also|List of historical harbour cranes}} [[File:1742 build crane, used for mounting masts to large sailing vessels. Copenhagen, Denmark, Mastekranen, Holmen. Copenhagen, Denmark.JPG|thumb|right|A crane constructed in 1742, used for mounting [[mast (sailing)|masts]] to large sailing vessels. Copenhagen, Denmark]] [[File:Cape Town (ZA), Waterfront, Kran -- 2024 -- 2907.jpg|thumb|Detail view of a (small) crane in the harbour, [[V&A Waterfront]]]] According to the "present state of knowledge" unknown in antiquity, stationary harbor cranes are considered a new development of the Middle Ages.<ref name="Matheus 1996, 345" /> The typical harbor crane was a pivoting structure equipped with double treadwheels. These cranes were placed docksides for the loading and unloading of cargo where they replaced or complemented older lifting methods like [[see-saw]]s, [[winch]]es and [[Yard (sailing)|yards]].<ref name="Matheus 1996, 345" />

Two different types of harbor cranes can be identified with a varying geographical distribution: While gantry cranes, which pivoted on a central vertical axle, were commonly found at the Flemish and Dutch coastside, German sea and inland harbors typically featured tower cranes where the windlass and treadwheels were situated in a solid tower with only jib arm and roof rotating.<ref name="Matheus 1996, 346">{{harvnb|Matheus|1996|p=346}}</ref> Dockside cranes were not adopted in the Mediterranean region and the highly developed Italian ports where authorities continued to rely on the more labor-intensive method of unloading goods by ramps beyond the Middle Ages.<ref>{{harvnb|Matheus|1996|p=347}}</ref>

Unlike construction cranes where the work speed was determined by the relatively slow progress of the masons, harbor cranes usually featured double treadwheels to speed up loading. The two treadwheels whose diameter is estimated to be 4 m or larger were attached to each side of the axle and rotated together.<ref name="Matheus 1996, 345" /> Their capacity was 2–3 tons, which apparently corresponded to the customary size of marine cargo.<ref name="Matheus 1996, 345" /> Today, according to one survey, fifteen treadwheel harbor cranes from pre-industrial times are still extant throughout Europe.<ref>These are Bergen, Stockholm, Karlskrona (Sweden), Kopenhagen (Denmark), Harwich (England), Gdańsk (Poland), Lüneburg, Stade, Otterndorf, Marktbreit, Würzburg, Östrich, Bingen, Andernach and Trier (Germany). Cf. {{harvnb|Matheus|1996|p=346}}</ref> Some harbour cranes were specialised at mounting masts to newly built sailing ships, such as in [[Gdańsk]], [[Cologne]] and [[Bremen]].<ref name="Matheus 1996, 346" /> Beside these stationary cranes, [[crane vessel|floating cranes]], which could be flexibly deployed in the whole port basin came into use by the 14th century.<ref name="Matheus 1996, 346" />

A [[sheer hulk]] (or shear hulk) was used in shipbuilding and repair as a [[Crane vessel|floating crane]] in the days of [[sailing ship]]s, primarily to place the lower [[mast (sailing)|mast]]s of a ship under construction or repair. Booms known as [[sheers]] were attached to the base of a hulk's lower masts or beam, supported from the top of those masts. [[Block and tackle|Blocks and tackle]] were then used in such tasks as placing or removing the lower masts of the vessel under construction or repair. These lower masts were the largest and most massive single timbers aboard a ship, and erecting them without the assistance of either a sheer hulk or land-based [[masting sheer]] was extremely difficult.<ref>{{cite encyclopedia|last=((Britannica, The Editors of Encyclopaedia)) |title=shipyard |encyclopedia=Encyclopedia Britannica |date=1 May 2023 |url=https://www.britannica.com/technology/shipyard |access-date=8 June 2023 }}</ref>

The concept of sheer hulks originated with the Royal Navy in the 1690s, and persisted in Britain until the early nineteenth century. Most sheer hulks were decommissioned warships; ''Chatham'', built in 1694, was the first of only three purpose-built vessels.<ref>[http://threedecks.org/index.php?display_type=show_ship&id=7539 Threedecks: British sheer hulk 'Chatham' (1694)]</ref> There were at least six sheer hulks in service in Britain at any time throughout the 1700s. The concept spread to France in the 1740s with the commissioning of a sheer hulk at the port of Rochefort.<ref name=Gardiner>{{cite book|editor1-first=Robert|editor1-last=Gardiner|first=Brian|last=Lavery|chapter=Static Vessels|title=The Line of Battle: The Sailing Warship 1650–1840 |publisher=Conway Maritime Press |year=1992 |pages=106–107 |isbn=0-85177-954-9}}</ref>

===Early modern age===

A lifting tower similar to that of the ancient Romans was used to great effect by the [[Renaissance architecture|Renaissance architect]] [[Domenico Fontana]] in 1586 to relocate the 361 t heavy [[List of obelisks in Rome|Vatican obelisk]] in Rome.<ref>{{harvnb|Lancaster|1999|p=428}}</ref> From his report, it becomes obvious that the coordination of the lift between the various pulling teams required a considerable amount of concentration and discipline, since, if the force was not applied evenly, the excessive stress on the ropes would make them rupture.<ref>{{harvnb|Lancaster|1999|pp=436–437}}</ref>

Cranes were also used domestically during this period. The chimney or fireplace crane was used to swing pots and kettles over the fire and the height was adjusted by a [[Trammel hook|trammel]].<ref>[https://www.victorianweb.org/technology/domestic/cooking.html The Victorian Web]</ref>{{Clear}}

<gallery mode="packed" heights="140px" caption="Examples of early modern cranes"> File:1586 Rome obelisk erection.jpg|Erection of the [[List of obelisks in Rome|Vatican obelisk]] in 1586 by means of a lifting tower File:Kölner Dom 1868 001.jpg|alt=Old photo of a 15th-century crane on the south tower of the cathedral before completion|An 1868 photo of a 15th-century crane on the unfinished south tower of [[Cologne Cathedral]] File:Fireplace crane02.jpg|Fireplace crane </gallery>

===Industrial revolution=== [[File:William george armstrong.jpg|thumb|upright|[[William Armstrong, 1st Baron Armstrong|Sir William Armstrong]], inventor of the hydraulic crane]] With the onset of the [[Industrial Revolution]] the first modern cranes were installed at harbours for loading cargo. In 1838, the industrialist and businessman [[William Armstrong, 1st Baron Armstrong|William Armstrong]] designed a water-powered [[hydraulic crane]]. His design used a ram in a closed cylinder that was forced down by a pressurized fluid entering the cylinder and a valve regulated the amount of fluid intake relative to the load on the crane.<ref>{{cite web|url=http://www.machine-history.com/Armstrong%20Hydraulic%20Crane|title=Armstrong Hydraulic Crane|publisher=Machine-History.Com|archive-url=https://web.archive.org/web/20140110235111/http://www.machine-history.com/Armstrong%20Hydraulic%20Crane|archive-date=10 January 2014}}</ref> This mechanism, the [[hydraulic jigger]], then pulled on a chain to lift the load.

In 1845 a scheme was set in motion to provide piped water from distant reservoirs to the households of [[Newcastle upon Tyne|Newcastle]]. Armstrong was involved in this scheme and he proposed to Newcastle Corporation that the excess water pressure in the lower part of town could be used to power one of his hydraulic cranes for the loading of coal onto barges at the [[Quayside]]. He claimed that his invention would do the job faster and more cheaply than conventional cranes. The corporation agreed to his suggestion, and the experiment proved so successful that three more hydraulic cranes were installed on the Quayside.<ref name="Dougan">{{cite book |author=Dougan, David |year=1970 |title=The Great Gun-Maker: The Story of Lord Armstrong|publisher=Sandhill Press Ltd |isbn=0-946098-23-9}}</ref>

The success of his hydraulic crane led Armstrong to establish the [[Armstrong Whitworth|Elswick works]] at [[Newcastle upon Tyne|Newcastle]], to produce his [[hydraulic machinery]] for cranes and bridges in 1847. His company soon received orders for hydraulic cranes from Edinburgh and Northern Railways and from [[Port of Liverpool|Liverpool Docks]], as well as for hydraulic machinery for dock gates in [[Grimsby]]. The company expanded from a workforce of 300 and an annual production of 45 cranes in 1850, to almost 4,000 workers producing over 100 cranes per year by the early 1860s.<ref name="Dougan" />

Armstrong spent the next few decades constantly improving his crane design; his most significant innovation was the [[hydraulic accumulator]]. Where water pressure was not available on site for the use of hydraulic cranes, Armstrong often built high water towers to provide a supply of water at pressure. However, when supplying cranes for use at [[New Holland, North Lincolnshire|New Holland]] on the [[Humber Estuary]], he was unable to do this, because the foundations consisted of sand. He eventually produced the hydraulic accumulator, a cast-iron cylinder fitted with a plunger supporting a very heavy weight. The plunger would slowly be raised, drawing in water, until the downward force of the weight was sufficient to force the water below it into pipes at great pressure. This invention allowed much larger quantities of water to be forced through pipes at a constant pressure, thus increasing the crane's load capacity considerably.<ref>{{cite book |author=McKenzie, Peter |year=1983 |title=W.G. Armstrong: The Life and Times of Sir William George Armstrong, Baron Armstrong of Cragside|publisher=Longhirst Press |isbn=0-946978-00-X}}</ref>

One of his cranes, commissioned by the [[Italian Navy]] in 1883 and in use until the mid-1950s, is still standing in [[Venice]], where it is now in a state of disrepair.<ref>{{cite news|date=20 May 2010|title=Newcastle crane 'priceless' part of Venetian heritage|url=https://news.bbc.co.uk/local/tyne/hi/people_and_places/history/newsid_8694000/8694543.stm|publisher=BBC|access-date=8 November 2013}}</ref>

==Mechanical principles== Crane design requires balancing three fundamental considerations: adequate [[Working load limit|load capacity]], [[Structural stability|stability]] against tipping, and [[structural failure]] prevention. Stability is achieved through [[Moment (physics)|moment equilibrium]], where permitted loads are significantly less than tipping loads—typically 75-85% in the [[United States|US]] and 70-80% in [[Europe]]. [[Soil mechanics|Ground conditions]] critically affect stability, with [[Outrigger|outrigger pads]] exerting 50-200 [[Pascal (unit)|kPa]] [[pressure]]. The [[Dynamic load|dynamic lift factor]] (DLF) accounts for [[Transient response|transient forces]] from [[Hoist (device)|hoisting]] [[acceleration]], crane motion, [[Wind wave|wave-induced]] [[Ship motions|vessel motions]] in [[Offshore construction|offshore applications]], and [[Structural load|wind effects]] (20 m/s in-service, 42 m/s out-of-service). [[Human factors and ergonomics|Human factors]] and modern [[Control system|electronic control systems]] significantly influence [[Dynamic load|dynamic loading]]. International standards including [[American Society of Mechanical Engineers|ASME]] B30.5 and [[European Standard|EN]] 13000 establish safety requirements, while sophisticated [[instrumentation]] such as [[Load cell|load cells]], [[Accelerometer|accelerometers]], and [[Strain gauge|strain gauges]] validate crane performance during [[type approval]] testing.<ref>{{cite web| title = Determining the nature of crane failure using finite element analysis| website = Siemens Digital Industries Software| year = 2020| url = https://blogs.sw.siemens.com/femap/femto-engineering-determines-nature-of-crane-failure-using-femap/| access-date = 18 November 2025}}</ref>

<gallery mode="packed" heights="180px"> File:El movimiento de una grua.ogg|A [[tower crane]] can swing its boom left and right, dolly its car, and lift and lower its load File:Shipyard Ishibras Ishikawajima Sermetal.JPG|Failed crane in Sermetal Shipyard, former [[IHI Corporation|Ishikawajima]] do Brasil – [[Rio de Janeiro]], caused by a lack of maintenance and misuse of the equipment File:Automated Crane With Utensils.jpg|Cranes can mount many different fittings, such as hooks, [[pulley|blocks]], spreader bars, and "choker" lines, depending on load </gallery>

===Stability===

For stability, the sum of all [[Moment (physics)|moments]] about the base of the crane must be close to zero so that the crane does not overturn.<ref name="Brain-2000">{{cite web| last = Brain| first = Marshall| title = How Tower Cranes Work| website = HowStuffWorks| date = April 2000| url = http://science.howstuffworks.com/transport/engines-equipment/tower-crane.htm| access-date = 2 April 2014}}</ref> The principle of [[moment (physics)|moment equilibrium]] (ΣM = 0) is fundamental to crane design, where M represents moments about the crane's [[center of rotation]]. In practice, the magnitude of load that is permitted to be lifted (called the "rated load" in the [[United States]]) is some value less than the load that will cause the crane to tip, thus providing a [[factor of safety|safety margin]].

====National and International Standards==== Under [[United States]] standards for [[mobile crane]]s, the stability-limited rated load for a [[crawler crane]] is 75% of the tipping load, and for outrigger-supported cranes is 85% of the tipping load. These requirements are established by the [[American Society of Mechanical Engineers]] in the volume ASME B30.5-2018 ''Mobile and Locomotive Cranes''.<ref name="ASME-B30">{{cite web| title = What Is the ASME B30 Safety Standard for Cranes, Hoists, and Rigging?| website = Mazzella Companies| date = 14 July 2025| url = https://www.mazzellacompanies.com/news/what-is-the-asme-b30-safety-standard/| access-date = 18 November 2025}}</ref><ref name="Crane-Guide-2022">{{cite web| title = ASME B30.5 Standard Sets Requirements for Mobile Crane Rigger and Signalperson Qualifications| website = Crane Equipment Guide| date = 21 August 2022| url = https://www.craneequipmentguide.com/asme-b30-5-standard-sets-requirements-for-mobile-crane-rigger-and-signalperson-qualifications/84831| access-date = 18 November 2025}}</ref>

[[European Union|European]] standards (EN 13000:2010) adopt similar principles but with different [[factor of safety|safety factors]] reflecting different regulatory philosophies regarding [[risk tolerance]].<ref name="EN-13000">EN 13000:2010 ''Cranes – Mobile cranes''. European Committee for Standardization (CEN), section 4.2.1.</ref> For mobile cranes on [[outrigger]]s, the rated capacity under European standards is typically 80% of the tipping load, while [[crawler crane]]s are rated at 70% of the tipping load.<ref name="EN-13000" />

====Safety Margins and Design Life==== [[Factor of safety|Safety margins]] typically range between 10 and 25% above a crane's rated capacity. However, regular operation near or above rated capacity significantly increases [[wear]] on components, resulting in higher [[maintenance]] costs and shortened operational lifespan. The design must account for [[fatigue (material)|fatigue cycles]], with typical design life of 20 years or 2 million load cycles per [[International Organization for Standardization|ISO]] 12482-1:2014.<ref>{{cite web| title = ISO 12482:2014 - Cranes — Monitoring for crane design working period| website = International Organization for Standardization| date = 5 December 2014| url = https://www.iso.org/standard/51536.html| access-date = 18 November 2025}}</ref>

====Ground Conditions and Soil Bearing==== For [[mobile crane]]s on [[outrigger]]s, stability depends critically on ground conditions. The typical outrigger pad exerts [[pressure]]s of 50-200 [[Pascal (unit)|kPa]] (7-29 [[Pounds per square inch|psi]]). [[Engineering]] guidelines require [[soil]] [[bearing capacity]] assessments before crane setup, with mandatory use of timber mats or engineered [[Box crib|cribbing]] when soil capacity is below 150 kPa. Inadequate ground preparation is a leading cause of crane tipping accidents, particularly in [[construction site]]s with variable [[soil]] conditions.<ref name="OSHA-1402">{{cite web| title = OSHA 1926.1402 - Ground Conditions| website = OSHA.gov| url = https://www.osha.gov/laws-regs/regulations/standardnumber/1926/1926.1402| access-date = 18 November 2025}}</ref>

====Offshore and Marine Applications==== Standards for cranes mounted on [[ship]]s or [[Oil platform|offshore platforms]] are somewhat stricter because of the dynamic load on the crane due to [[Ship|vessel]] motion.<ref name="Perez-2018">{{cite journal| last1 = Perez| first1 = Tristan| last2 = Wilhelmsen| first2 = Lasse| title = Dynamic Interaction of a Heavy Crane and a Ship in Wave Motion| journal = Modeling, Identification and Control| volume = 39| issue = 1| pages = 1–13| year = 2018| doi = 10.4173/mic.2018.1.1}}</ref> For loads not associated with crewed operations, allowable loads must factor in dynamic [[acceleration]]s including 1.75 [[g-force|g]] vertical, 0.75 g longitudinal, and 0.75 g transverse acceleration, meaning a 2000 kg static load requires crane capacity for 3500 kg at sea. Additionally, the stability of the vessel or platform must be considered.<ref name="Noh-2022">{{cite journal| last1 = Noh| first1 = Yohan| last2 = Park| first2 = Kwang-Phil| last3 = Hong| first3 = Sa Young| title = Dynamic Analysis and Extreme Response Evaluation of Lifting Operation of the Offshore Wind Turbine Jacket Foundation Using a Floating Crane Vessel| journal = Applied Sciences| volume = 13| issue = 1| year = 2022| doi = 10.3390/app13010283| doi-access = free}}</ref>

====Pedestal-Mounted Cranes==== For stationary pedestal or kingpost mounted cranes, the [[moment (physics)|moment]] produced by the boom, jib, and load is resisted by the pedestal base or kingpost. [[Stress (mechanics)|Stress]] within the base must be less than the [[yield (engineering)|yield stress]] of the material or the crane will fail.<ref name="Wahrhaftig-2022">{{cite journal| last1 = Wahrhaftig| first1 = Alexandre de M.| last2 = Silva| first2 = Márcio A.| last3 = Brasil| first3 = Reyolando M.L.R.F.| title = Mechanical Performance and Failure Mode Research on the Braced Frame Joints of Towers| journal = Frontiers in Built Environment| volume = 8| year = 2022| doi = 10.3389/fbuil.2022.891039| doi-broken-date = 19 November 2025| doi-access = free}}</ref> The design must account for [[fatigue (material)|fatigue loading]], wind-induced [[oscillation]]s, and [[thermal expansion]] effects over the crane's operational lifetime.

===Dynamic Lift Factor=== [[File:Camion GMC 1942 Saint-Cybranet.jpg|thumb|right|[[HIAB]] [[knuckle-boom crane]] mounted on bed of a 1942 US Army truck]]

====Overview==== [[File:Crane testing bags on an offshore support vessel.jpg|alt=Water-filled crane test bags suspended over the sea during offshore crane load testing operations on a vessel.|thumb|Offshore crane load testing using water-filled test weights]] The dynamic lift factor (DLF), also known as the design dynamic factor, is a critical parameter in crane design and operation. It accounts for the dynamic effects that can increase the load on a crane's structure and components during lifting operations.<ref name="DNV-2011">{{cite book| title = Standard for Certification 2.22 Lifting Appliances| publisher = Det Norske Veritas AS| date = October 2011}}</ref><ref>{{cite web| title = Understanding Offshore Lifting Operations And Engineering Analysis| website = Marine Insight| date = 7 May 2024| url = https://www.marineinsight.com/offshore/understanding-offshore-lifting-operations-and-engineering-analysis/| access-date = 18 November 2025}}</ref> These effects include hoisting [[acceleration]] and deceleration of the load, crane movement such as [[slewing]] or [[luffing]], swinging of suspended loads, [[wind force]]s acting on the crane, the load and the rigging, and operator error or other unexpected events.<ref>{{cite journal| last1 = Vaughan| first1 = J.| last2 = Yano| first2 = A.| last3 = Singhose| first3 = W.| title = Effects of hoisting on the input shaping control of gantry cranes| journal = Control Engineering Practice| volume = 8| issue = 10| pages = 1159–1165| year = 2000| doi = 10.1016/S0967-0661(00)00054-X}}</ref><ref>{{cite journal| title = Dynamic Reaction Forces of an Overhead Crane on Lifting| journal = Journal of Civil Engineering and Management| volume = 17| issue = 4| pages = 496–506| year = 2011| doi = 10.3846/13923730.2011.619325}}</ref>

The DLF for a new crane design can be determined with analytical calculations and mathematical models following the relevant design [[Specification (technical standard)|specifications]]. More sophisticated methods, such as [[finite element analysis]] or other simulation techniques, may also be used to model the crane's behavior under various loading conditions, as deemed appropriate by the designer or certifying authority. To verify the actual DLF, control load tests can be conducted on the completed crane using instrumentation such as [[Load cell|load cells]], [[Accelerometer|accelerometers]], and [[Strain gauge|strain gauges]]. This process is usually part of the crane's [[type approval]].<ref name="DNV-2011" />

====Practical DLF Values==== [[Jib crane]]s typically have a lower DLF (<math display="inline">\psi\approx1.3</math>) compared to traveling [[gantry crane]]s (<math>\psi \approx 1.6</math>) because they are stiffer.<ref>{{cite book| title = FEM 1.001 Rules for the design of hoisting appliances| publisher = Federation Europeenne de la Manutention| date = October 1998| edition = 3rd}}</ref> For [[grab bucket]] cranes, the DLF can increase by 20% to 30% reflecting the [[shock load]]s caused by the release of the lifted material.<ref name="DNV-2011" /> The DLF generally decreases as the [[mass]] of the lifted object increases, as cranes tend to operate at lower [[velocity|velocities]] with heavier loads to ensure safety and stability.

====Offshore Considerations==== In offshore lifting, where the crane and/or lifted object are on a [[buoyancy|floating]] [[Ship|vessel]], the DLF is higher compared to onshore lifts because of the additional movement caused by [[wave action]].<ref name="DNV-2011" /><ref name="Perez-2018" /> [[Wave motion|Wave-induced vessel motions]] including [[Ship motions|heave]], [[Ship motions|pitch]], and [[Ship motions|roll]] are translated down the lifting wire, resulting in submerged loads being [[acceleration|accelerated]] in response to forces induced by ship motions, with peak [[tension (physics)|tension]] equal to [[weight]] plus [[Inertia|inertial]] effects plus [[drag (physics)|drag]] effects. The DLF further increases when lifting objects underwater or through the [[splash zone]].<ref>{{cite book| title = Standard for certification No. 2.7-3 Portable offshore units| date = May 2011| publisher = Det Norske Veritas}}</ref> For offshore lifts, the DLF typically decreases from 1.3 at 100 [[tonne]]s to 1.1 at 2500 tonnes as heavier loads require slower, more controlled operations.<ref>{{cite book| title = 0027/ND Guidelines for Marine Lifting Operations| date = 2010| publisher = GL Noble Denton}}</ref>

====Wind Effects==== Design [[wind speed]]s per American Society of Civil Engineers (ASCE) 7-16 and [[International Organization for Standardization|ISO]] 4302:2016 are 20 [[Meter per second|m/s]] (72 [[Kilometers per hour|km/h]]) for in-service conditions and 42 m/s (150 km/h) for out-of-service survival.<ref name="ASCE-7">{{cite book| title = ASCE 7-16 Minimum Design Loads and Associated Criteria for Buildings and Other Structures| publisher = American Society of Civil Engineers| year = 2016| pages = Section 29}}</ref> The [[wind force]] on a load can be calculated as <math>F_{\text{wind}} = 0.613 \times C_d \times A \times V^2</math> where <math>C_d</math> is the [[drag coefficient]] (typically 1.0-2.0 depending on load shape), <math>A</math> is the projected [[area]] in m<sup>2</sup>, and <math>V</math> is wind speed in m/s.<ref name="ASCE-7" />

====Human Factors==== [[Research]] demonstrates that [[human factors]] significantly influence [[Dynamic load|dynamic loading]] events during crane operations.<ref>{{cite journal| last1 = Nordström| first1 = J.| last2 = Badia-i-Mompel| first2 = P.| last3 = Witasp| first3 = A.| last4 = Schwarz| first4 = A.| last5 = Evenepoel| first5 = P.| last6 = Moor| first6 = M. B.| last7 = Wennberg| first7 = L.| last8 = Saez-Rodriguez| first8 = J.| last9 = Wernerson| first9 = A.| last10 = Olauson| first10 = H.| title = Human reliability of the intelligent construction site tower crane driver-machine interface| journal = PLOS ONE| date = 16 October 2024| volume = 19| issue = 10| article-number = e0311613| doi = 10.1371/journal.pone.0311613| doi-access = free| pmid = 39471208| pmc = 11521294}}</ref> Modern cranes incorporate [[Electronic circuit|electronic]] [[control system]]s that limit [[acceleration]] rates through "[[soft start]]" mechanisms, reducing DLF and improving operational smoothness while reducing [[Machine (mechanical)|mechanical]] [[stress (mechanics)|stress]] on crane components.

====Formulas==== The working load is the total [[weight]] that a crane is designed to safely lift under normal operating conditions:<ref name="DNV-2011" />

:<math>W= g\cdot(m_{\text{wll}} + m_a)</math>

where <math>W</math> is the working load, <math>g</math> is the [[acceleration]] of gravity (9.81 m/s²), <math>m_{\text{wll}}</math> is the maximum lifted [[mass]] (working load limit or safe working load), and <math>m_a</math> is the mass of lifting appliances or parts of the crane that move with the lifted mass.

The DLF is then used as a [[multiplier]] to determine the [[force]] applied to the crane structure and components:<ref name="DNV-2011" />

:<math>F_d= \psi \cdot W</math>

where <math>F_d</math> is the [[design]] force and <math>\psi</math> is the DLF.

The DLF can be calculated using:<ref name="DNV-2011" /><ref>{{cite book| title = FEM 5.015: Recommendation for the calculation of dynamic factors| publisher = Federation Europeenne de la Manutention| year = 2004| pages = 7–12}}</ref>

:<math>\psi=1+V_R\cdot\sqrt{C/(W\cdot g)}</math>

where <math>V_R</math> is relative [[velocity]] between lifted object and lifting equipment at the time of pick-up, and <math>C</math> is the [[stiffness]] of the crane [[system]] at the lifting point. The relative velocity is dependent on the crane's operational requirements and the system stiffness can be determined by [[calculation]] or [[Mechanical load|load]] [[Deflection (engineering)|deflection]] [[Mechanical testing|test]]s.<ref name="DNV-2011" />

====Instrumentation for DLF Measurement==== Modern type-approval tests employ sophisticated [[instrumentation]] to accurately measure dynamic loads during crane operation.<ref>{{cite book| title = ISO 20332:2016 Cranes — Proof of competence of steel structures| publisher = International Organization for Standardization| year = 2016| pages = 15–18}}</ref> [[Load cell]]s provide measurements with ±0.5% [[accuracy]] at full scale, while tri-[[Axis of rotation|axial]] [[accelerometer]]s capable of measuring [[acceleration]]s up to 100[[g-force|g]] are mounted on [[Jib (crane)|jib sections]] and [[Block and tackle|load blocks]]. [[Strain gauge]]s bonded to critical structural members measure [[stress (mechanics)|stress]] [[distribution]], and for offshore applications, [[Global Positioning System|GPS]] systems with ±2[[centimeter|cm]] positional accuracy track [[wave motion]] compensation. High-speed [[data logger]]s with [[sampling (statistics)|sampling]] rates of 500-1000 [[Hertz|Hz]] capture rapid dynamic response peaks that may be missed at lower sampling rates.

==Types== The crane types outlined in this section are categorized based on their primary area of application: {{div col}} * [[#Construction|Construction]] ** [[#Truck-mounted|Truck-mounted]] ** [[#Telescopic|Telescopic]] ** [[#Rough-terrain|Rough-terrain]] ** [[#All-terrain|All-terrain]] ** [[#Crawler|Crawler]] ** [[#Pick-and-carry|Pick-and-carry]] ** [[#Carry deck|Carry deck]] ** [[#Telescopic handler|Telescopic handler]] ** [[#Block setting|Block setting]] ** [[#Tower|Tower]] ** [[#Climbing crane|Climbing crane]]

* [[#Marine|Marine]] ** [[#Floating|Floating]] ** [[#Deck|Deck]] * [[#Other types|Other types]] ** [[#Railroad|Railroad]] ** [[#Aerial|Aerial]] {{div col end}} === Construction === ==== Truck-mounted ==== {{Main|Mobile crane|}}

The most basic [[truck]]-mounted crane configuration is a "boom truck" or "lorry loader", which features a rear-mounted rotating telescopic-boom crane mounted on a commercial truck chassis.<ref>[https://www.constructionequipment.com/boom-truck ''Boom Truck'', constructionequipment.com]</ref><ref>{{Cite web|url=https://www.phelanhaulage.com/what-is-a-hiab|title=What Is A HIAB? Is a HIAB A Lorry Loader?|access-date=2021-01-24}}</ref> [[File:Tram repair in Dnipro.jpg|thumb|A crane vehicle in [[Dnipro]], Ukraine.]] Larger, heavier duty, purpose-built "truck-mounted" cranes are constructed in two parts: the carrier, often called the ''lower'', and the lifting component, which includes the boom, called the ''upper''. These are mated together through a turntable, allowing the upper to swing from side to side. These modern hydraulic truck cranes are usually single-engine machines, with the same engine powering the undercarriage and the crane. The upper is usually powered via hydraulics run through the turntable from the pump mounted on the lower. In older model designs of hydraulic truck cranes, there were two engines. One in the lower pulled the crane down the road and ran a hydraulic pump for the outriggers and jacks. The one in the upper ran the upper through a hydraulic pump of its own. Many older operators favor the two-engine system due to leaking seals in the turntable of aging newer design cranes. Hiab invented the world's first hydraulic truck mounted crane in 1947.<ref>{{Cite web|url=http://www.sunfab.com/about-us/history.aspx|title=History | Sunfab|access-date=6 April 2016|archive-date=12 March 2016|archive-url=https://web.archive.org/web/20160312140114/http://www.sunfab.com/about-us/history.aspx}}</ref> The name, Hiab, comes from the commonly used abbreviation of Hydrauliska Industri AB, a company founded in Hudiksvall, Sweden 1944 by Eric Sundin, a ski manufacturer who saw a way to utilize a truck's engine to power loader cranes through the use of hydraulics.

Generally, these cranes are able to travel on highways, eliminating the need for special equipment to transport the crane unless weight or other size constrictions are in place such as local laws. If this is the case, most larger cranes are equipped with either special trailers to help spread the load over more axles or are able to disassemble to meet requirements. An example is counterweights. Often a crane will be followed by another truck hauling the counterweights that are removed for travel. In addition some cranes are able to remove the entire upper. However, this is usually only an issue in a large crane and mostly done with a conventional crane such as a Link-Belt HC-238. When working on the job site, [[outrigger]]s are extended horizontally from the chassis then vertically to level and stabilize the crane while stationary and [[Hoist (device)|hoisting]]. Many truck cranes have slow-travelling capability (a few miles per hour) while suspending a load. Great care must be taken not to swing the load sideways from the direction of travel, as most anti-tipping stability then lies in the stiffness of the chassis suspension. Most cranes of this type also have moving counterweights for stabilization beyond that provided by the outriggers. Loads suspended directly aft are the most stable, since most of the weight of the crane acts as a counterweight. Factory-calculated charts (or [[Safe Load Indicator|electronic safeguards]]) are used by crane operators to determine the maximum safe loads for stationary (outriggered) work as well as (on-rubber) loads and travelling speeds.

Truck cranes range in lifting capacity from about {{convert|14.5|ST|LT t|lk=on}} to about {{convert|2240|ST|LT t|0|abbr=}}.<ref>{{Cite web|url=https://www.simscrane.com/zoomlion-qay2000-completes-overload-tests-successfully/|title=Zoomlion QAY2000 Completes Overload Tests Successfully|date=17 December 2013|access-date=2021-01-24}}</ref><ref>{{Cite web|url=https://www.phelanhaulage.com/what-can-you-lift-with-a-hiab|title=What Can You Lift With A HIAB?|access-date=2021-01-24}}</ref> Although most only rotate about 180 degrees, the more expensive truck mounted cranes can turn a full 360 degrees. <gallery mode="packed" heights="140" caption="Examples of truck mounted cranes"> File:Автомобильный кран Железнодорожных войск РФ.png|Automobile crane of the Railway Troops of Russia File:Truck-mounted crane building a bridge.jpg|Truck mounted crane building a bridge File:Truck crane.jpg|A truck-mounted crane in road travel configuration </gallery>

====Loader==== [[File:Hydraulic Truck Crane.jpg|thumb|Loader crane using a jib extension]] A loader crane (also called a ''[[knuckle-boom crane]]'' or ''articulating crane'') is a hydraulically powered articulated arm fitted to a [[truck]] or [[Trailer (vehicle)|trailer]], and is used for loading/unloading the vehicle cargo. The numerous jointed sections can be folded into a small space when the crane is not in use. One or more of the sections may be [[telescopic cylinder|telescopic]]. Often the crane will have a degree of automation and be able to unload or stow itself without an operator's instruction.

Unlike most cranes, the operator must move around the vehicle to be able to view his load; hence modern cranes may be fitted with a portable cabled or radio-linked control system to supplement the crane-mounted hydraulic control levers.

In the United Kingdom and Canada, this type of crane is often known colloquially as a "[[HIAB|Hiab]]", partly because this manufacturer invented the loader crane and was first into the UK market, and partly because the distinctive name was displayed prominently on the boom arm.<ref name="hiab">{{cite web |title=Hiab Loader Cranes - Custom-made cranes for highest productivity |url=http://www.cargotec.com/en-global/hiab/products/Loader-cranes/Pages/default.aspx |archive-url=https://web.archive.org/web/20130322045427/http://www.cargotec.com/en-global/hiab/products/Loader-cranes/Pages/default.aspx |archive-date=22 March 2013}}</ref>

A '''rolloader''' crane is a loader crane mounted on a chassis with wheels. This chassis can ride on the trailer. Because the crane can move on the trailer, it can be a light crane, so the trailer is allowed to transport more goods.

====Telescopic==== [[File:Telescopic crane, SouthGate, Bath.jpg|thumb|A telescopic mobile crane with truss luffing jib]]

A telescopic crane has a boom that consists of a number of tubes fitted one inside the other. A [[hydraulic cylinder]] or other powered mechanism extends or retracts the tubes to increase or decrease the total length of the boom. These types of booms are often used for short term construction projects, rescue jobs, lifting boats in and out of the water, etc. The relative compactness of telescopic booms makes them adaptable for many mobile applications.

Though not all telescopic cranes are mobile cranes, many of them are truck-mounted.

A telescopic tower crane has a telescopic mast and often a superstructure (jib) on top so that it functions as a tower crane. Some telescopic tower cranes also have a telescopic jib.{{Clear}}

==== Rough-terrain ==== [[File:Omega 18.jpg|thumb|Rough terrain crane]] A rough terrain crane has a [[wikt:boom#Noun 2|boom]] mounted on an [[Chassis|undercarriage]] atop four rubber tires that is designed for [[off-road]] pick-and-carry operations. Outriggers are used to level and stabilize the crane for hoisting.<ref>{{Cite news|url=https://civilguides.com/different-types-of-cranes/|title=Top 12 Different Types of Cranes used in Construction Works.|last=Khan|first=Inamullah|date=2017-07-14|work=CivilGuides|access-date=2018-01-03|language=en-US}}</ref>

These telescopic cranes are single-engine machines, with the same engine powering the undercarriage and the crane, similar to a crawler crane. The engine is usually mounted in the undercarriage rather than in the upper, as with crawler crane. Most have 4 wheel drive and 4 wheel steering for traversing tighter and slicker terrain than a standard truck crane, with less site prep.

==== All-terrain ==== [[File:GMK3050 All Terrain Crane.jpg|thumb|All terrain crane]] An all-terrain crane is a hybrid combining the roadability of a truck-mounted and on-site maneuverability of a rough-terrain crane. It can both travel at speed on public roads and maneuver on rough terrain at the job site using all-wheel and crab steering.

AT's have 2–12 axles and are designed for lifting loads up to {{convert|2000|t|ST LT|lk=on|0|abbr=}}.<ref>{{cite web |title=Zoomlion QAY 2000 |url=https://www.youtube.com/watch?v=RdfktW1TY6Y |archive-url=https://web.archive.org/web/20200404071954/https://www.youtube.com/watch?v=RdfktW1TY6Y |archive-date=4 April 2020 |access-date=1 June 2008 |website=[[YouTube]]}}</ref>

==== Crawler ==== [[File:Crawler crane 2.jpg|thumb|Crawler crane]] A crawler crane has its boom mounted on an undercarriage fitted with a set of [[Continuous track|crawler tracks]] that provide both stability and mobility. Crawler cranes range in lifting capacity from about {{convert|40|to|4000|LT|ST t|1}} as seen from the [[XGC88000 crawler crane]].<ref>{{Cite web|url=https://www.cranesy.com/world-no-1-sany-xcmg-xgc88000-crawler-crane/|title=World NO. 1 – SANY XCMG XGC88000 Crawler Crane - Cranesy|date=21 January 2013|access-date=2021-01-24}}</ref>

The main advantage of a crawler crane is its ready mobility and use, since the crane is able to operate on sites with minimal improvement and stable on its tracks without outriggers. Wide tracks spread the weight out over a great area and are far better than wheels at traversing soft ground without sinking in. A crawler crane is also capable of traveling with a load. Its main disadvantage is its weight, making it difficult and expensive to transport. Typically a large crawler must be disassembled at least into boom and cab and moved by trucks, rail cars or ships to its next location.<ref>{{Cite news|url=https://definecivil.com/types-of-cranes/|title=15 Types of Cranes used in Construction (SURPRISE List)|date=2018-09-21|work=Define Civil|access-date=2018-09-26|language=en-US}}</ref>

==== Pick-and-carry ==== [[File:Crane (7113665505).jpg|thumb|right|A pick-and-carry crane]] A pick and carry crane is similar to a mobile crane in that is designed to travel on public roads; however, pick and carry cranes have no stabiliser legs or outriggers and are designed to lift the load and carry it to its destination, within a small radius, then be able to drive to the next job. Pick and carry cranes are popular in Australia, where large distances are encountered between job sites. One popular manufacturer in Australia was Franna, who have since been bought by Terex, and now all pick and carry cranes are commonly called "Frannas", even though they may be made by other manufacturers. Nearly every medium- and large-sized crane company in Australia has at least one and many companies have fleets of these cranes. The capacity range is between {{convert|10 and 40|t|abbr=on}} as a maximum lift, although this is much less as the load gets further from the front of the crane. Pick and carry cranes have displaced the work usually completed by smaller truck cranes, as the set-up time is much quicker. Many steel fabrication yards also use pick and carry cranes, as they can "walk" with fabricated steel sections and place these where required with relative ease.

Smaller pick and carry cranes may be based on an articulated tractor chassis, with the boom mounted over the front wheels. In Australia these are popularly known as "wobbly cranes".<ref>{{cite web |last1=Alfonso |first1=Jack |title=Freo Group: a 50-year journey in cranes and logistics |url=https://www.cranesandlifting.com.au/freo-group-a-50-year-journey-in-cranes-and-logistics/ |website=Cranes & Lifting |date=24 June 2024}}</ref>

==== Carry-deck ==== A carry deck crane is a small 4 wheel crane with a 360-degree rotating boom placed right in the centre and an operators cab located at one end under this boom. The rear section houses the engine and the area above the wheels is a flat deck. Very much an American invention the Carry deck can hoist a load in a confined space and then load it on the deck space around the cab or engine and subsequently move to another site. The Carry Deck principle is the American version of the pick and carry crane and both allow the load to be moved by the crane over short distances.

==== Telescopic handler ==== {{main|Telescopic handler}}

[[File:FEMA - 10363 - Photograph by Mark Wolfe taken on 08-29-2004 in Florida.jpg|alt=|thumb|Bobcat Telescopic handler]] Telescopic handlers are [[forklift]]-like trucks that have a set of forks mounted on a telescoping extendable boom like a crane. Early telescopic handlers only lifted in one direction and did not rotate;<ref>[https://books.google.com/books?id=QCgDAAAAMBAJ&dq=popular+science+1930&pg=PA106 "Crane Lifts Big Load."] ''Popular Science'', August 1948, p. 106.</ref> however, several of the manufacturers have designed telescopic handlers that rotate 360 degrees through a turntable and these machines look almost identical to the Rough Terrain Crane. These new 360-degree telescopic handler/crane models have outriggers or stabiliser legs that must be lowered before lifting; however, their design has been simplified so that they can be more quickly deployed. These machines are often used to handle pallets of bricks and install frame trusses on many new building sites and they have eroded much of the work for small telescopic truck cranes. Many of the world's armed forces have purchased telescopic handlers and some of these are the much more expensive fully rotating types. Their off-road capability and their on site versatility to unload pallets using forks, or lift like a crane make them a valuable piece of machinery.

==== Block-setting crane ==== {{main|Block-setting crane}}

[[File:Kurrachee Harbour Works; Titan for laying blocks of Manora breakwater.jpg|thumb|upright|Parkes' ''Titan'' and the Manora breakwater, [[Karachi]]]] A '''block-setting crane''' is a form of crane. They were used for installing the large stone blocks used to build [[breakwater (structure)|breakwaters]], [[mole (architecture)|moles]] and [[pier|stone piers]].

==== Tower{{Anchor|Tower crane}} ==== In 1949, {{ill|Hans Liebherr|de}} built the first mobile tower crane, the ''TK10''.<ref name="liebherr/3781815">{{cite web |title=The Liebherr Group in the years 1949-1960 |url=https://www.liebherr.com/en-us/group/about-liebherr/history/1949-1960-3781815 |website=www.liebherr.com - Liebherr |language=en}}</ref><ref name="plant-planet/liebherr">{{cite web |last1=Peckyte |first1=Akvile |title=Brief History of Liebherr: Pioneers in Cranes |url=https://www.plant-planet.co.uk/brief-history-of-liebherr-pioneers-in-cranes/ |website=Plant Planet |access-date=17 July 2025 |date=14 July 2021}}</ref>

Tower cranes are a modern form of balance crane that consist of the same basic parts. Fixed to the ground on a concrete slab (and sometimes attached to the sides of structures), tower cranes often give the best combination of height and lifting capacity and are used in the construction of tall buildings. The base is then attached to the mast which gives the crane its height. Further, the mast is attached to the slewing unit (gear and motor) that allows the crane to rotate. On top of the slewing unit there are three main parts which are: the long horizontal jib (working arm), shorter counter-jib, and the operator's cab.

Optimization of tower crane location in the construction sites has an important effect on material transportation costs of a project,<ref>{{Cite journal |last1=Kaveh |first1=Ali |last2=Vazirinia |first2=Yasin |year=2018 |title=Optimization of tower crane location and material quantity between supply and demand points: A comparative study |journal=Periodica Polytechnica Civil Engineering |volume=62 |issue=3 |pages=732–745 |doi=10.3311/PPci.11816 |doi-access=free}}</ref> but site operators need to ensure they assess where the jib will oversail the property of other landowners and tenants as it rotates over the site. Under [[English law]] a landowner also owns the airspace above their property and developers will need to agree terms with adjacent property owners before oversailing their land.<ref>Institute of Party Wall Surveyors, [https://www.ipws.co.uk/advice/case-law/oversailing-what-is-it-and-why-is-it-a-concern-for-developers/ Oversailing: what is it and why is it a concern for developers?], accessed on 12 October 2024</ref>

The long horizontal jib is the part of the crane that carries the load. The counter-jib carries a counterweight, usually of concrete blocks, while the jib suspends the load to and from the center of the crane. The crane operator either sits in a cab at the top of the tower or controls the crane by radio remote control from the ground. In the first case the operator's cab is most usually located at the top of the tower attached to the turntable, but can be mounted on the jib, or partway down the tower. The lifting hook is operated by the crane operator using electric motors to manipulate wire rope cables through a system of sheaves. The hook is located on the long horizontal arm to lift the load which also contains its motor.

In order to hook and unhook the loads, the operator usually works in conjunction with a signaller (known as a "dogger", "rigger" or "swamper"). They are most often in radio contact, and always use hand signals. The rigger or dogger directs the schedule of lifts for the crane, and is responsible for the safety of the [[Rigging (material handling)|rigging]] and loads.

Tower cranes can achieve a height under hook of over 100 metres.<ref>Cranes and Access https://s3.eu-central-1.amazonaws.com/vertikal.net/ca-2009-1-p25-32_0881f7cc.pdf</ref> <gallery mode="packed" heights="140px" caption="Examples of tower cranes"> File:Tower Crane.JPG|Tower crane atop [[Mont Blanc]] File:Tower crane Dubai 2010.jpg|Tower crane cabin File:Кран с маховой стрелой.jpg|Tower crane with "luffing" [[Jib (crane)|jib]] File:Rotating tower crane.ogv|A tower crane rotates on its axis before lowering the lifting hook. File:Tower crane aerial 01.jpg|[[Teleoperation]] tower cranes at a [[Prefabricated building|prefabricated framed]] construction site </gallery>

===== Components ===== Tower cranes are used extensively in construction and other industry to hoist and move materials. There are many types of tower cranes. Although they are different in type, the main parts are the same, as follows: * '''Mast''': the main supporting tower of the crane. It is made of steel trussed sections that are connected together during installation. * '''Slewing unit''': the slewing unit sits at the top of the mast. This is the engine that enables the crane to rotate. * '''Operating cabin''': on most tower cranes the operating cabin sits just above the slewing unit. It contains the operating controls, load-movement indicator system (LMI), scale, anemometer, etc. * '''Jib''': the jib, or operating arm, extends horizontally from the crane. A "luffing" jib is able to move up and down; a fixed jib has a rolling trolley car that runs along the underside to move loads horizontally. * '''Counter jib''': holds counterweights, hoist motor, hoist drum and the electronics. (In many older tower crane designs the hoisting devices and electronics were located in the mast foot.) <ref>{{Cite web |last=Elliott |first=Matthew |date=2015-12-19 |title=Tower crane anatomy |url=https://www.cranecrews.com/crane-blog/tower-crane-anatomy |url-status=usurped |archive-url=https://web.archive.org/web/20151222094924/https://www.cranecrews.com/crane-blog/tower-crane-anatomy |archive-date=22 December 2015 |access-date=19 December 2015 |website=Crane & Rigging}}</ref> * '''Hoist winch''': the hoist winch assembly consists of the hoist winch (motor, gearbox, hoist drum, hoist rope, and brakes), the hoist motor controller, and supporting components, such as the platform. Many tower cranes have transmissions with two or more speeds. * '''Hook''': the hook is used to connect the material to the crane, suspended from the hoist rope either at the tip (on luffing jib cranes) or routed through the trolley (on hammerhead cranes). * '''Weights''': Large, moveable concrete counterweights are mounted toward the rear of the counterdeck, to compensate for the weight of the goods lifted and keep the center of gravity over the supporting tower.<ref>{{Cite web |date=2012-04-21 |title=the component of the tower cranes |url=http://www.86towercrane.com/article_4.htm |archive-url=https://web.archive.org/web/20120627015719/http://www.86towercrane.com/article_4.htm |archive-date=27 June 2012 |access-date=2012-08-15 |publisher=86towercrane.com}}</ref> [[File:Tower Cran break down (1).JPG|thumb|This crane's main [[Jib (crane)|jib]] failed due to an overload.]]

===== Assembly ===== A tower crane is usually assembled by a telescopic jib (mobile) crane of greater reach (also see "self-erecting crane" below) and in the case of tower cranes that have risen while constructing very tall skyscrapers, a smaller crane (or [[derrick]]) will often be lifted to the roof of the completed tower to dismantle the tower crane afterwards, which may be more difficult than the installation.<ref>{{Cite news |last=Croucher |first=Martin |date=11 November 2009 |title=Myth of 'Babu Sassi' Remains After Burj Cranes Come Down |url=http://www.khaleejtimes.com/displayarticle.asp?xfile=data/theuae/2009/November/theuae_November338.xml&section=theuae&col= |archive-url=https://web.archive.org/web/20121001080528/http://www.khaleejtimes.com/displayarticle.asp?xfile=data%2Ftheuae%2F2009%2FNovember%2Ftheuae_November338.xml&section=theuae&col= |archive-date=1 October 2012 |access-date=3 June 2011 |newspaper=[[Khaleej Times]]}}</ref>

Tower cranes can be operated by remote control, removing the need for the crane operator to sit in a cab atop the crane.

===== Operation ===== Each model and distinctive style of tower crane has a predetermined lifting chart that can be applied to any radii available, depending on its configuration. Similar to a mobile crane, a tower crane may lift an object of far greater mass closer to its center of rotation than at its maximum radius. An operator manipulates several levers and pedals to control each function of the crane.

===== Safety ===== When a tower crane is used in proximity to buildings, roads, power lines, or other tower cranes, a [[Tower Crane Anti-Collision System|tower crane anti-collision system]] is used. This operator support system reduces the risk of a dangerous interaction occurring between a tower crane and another structure.

In some countries, such as France, tower crane anti-collision systems are mandatory.<ref>{{cite web |last=Arnott |first=William |date=2019-12-04 |title=The real and hidden costs of tower crane anti-collision systems |url=https://www.cranesandlifting.com.au/the-real-and-hidden-costs-of-tower-crane-anti-collision-systems/}}</ref>

===== Self-erecting tower cranes ===== [[File:Origami Crane.JPG|thumb|A self-erecting tower crane folds and unfolds itself]]

Generally a type of pedestrian operated tower crane, self-erecting tower cranes are transported as a single unit and can be assembled by a qualified technician without the assistance of a larger mobile crane. They are bottom slewing cranes that stand on outriggers, have no counter jib, have their counterweights and ballast at the base of the mast, cannot climb themselves, have a reduced capacity compared to standard tower cranes, and seldom have an operator's cabin.

In some cases, smaller self-erecting tower cranes may have axles permanently fitted to the tower section to make maneuvering the crane onsite easier.

Tower cranes can also use a hydraulic-powered jack frame to raise themselves to add new tower sections without any additional other cranes assisting beyond the initial assembly stage. This is how it can grow to nearly any height needed to build the tallest skyscrapers when tied to a building as the building rises. The maximum unsupported height of a tower crane is around 265 ft.<ref>{{Cite web |date=2000-04-01 |title=How Tower Cranes Work |url=https://science.howstuffworks.com/transport/engines-equipment/tower-crane.htm |access-date=2019-08-23 |website=HowStuffWorks |language=en}}</ref> For a video of a crane getting taller, see "Crane Building Itself" on YouTube.<ref>{{YouTube|id=vx5Qt7_ECEE|title=Crane Building Itself}}</ref>

For another animation of such a crane in use, see "SAS Tower Construction Simulation" on YouTube.<ref>{{YouTube|id=44uiGFqqWNo|title=SAS Tower Construction Simulation}}</ref> Here, the crane is used to erect a scaffold, which, in turn, contains a gantry to lift sections of a bridge spire.

==== Climbing crane ==== [[file:Lagerwey Kletterkran WindEnergy Hamburg 2018.jpg|thumb|Climbing crane, at WindEnergy expo, 2018]]

Many tower cranes are designed to "jump" in stages, effectively lifting themselves to the next level. A specialty example of a climbing crane was introduced by Lagerwey Wind and [[Enercon]]{{Citation needed paragraph|date=August 2021}} to construct a [[wind turbine]] tower, where instead of erecting a large crane a smaller climbing crane can raise itself with the structure's construction, lift the generator housing to its top, add the rotor blades, then climb down.

=== Cargo handling === ====Rubber-tyred gantry crane==== {{Main|Rubber tyred gantry crane}}

==== Reach stacker ==== {{main|Reach stacker}}

[[File:CN Box Car Loader.JPG|thumb|[[Reach stacker]]]]

A reach stacker is a vehicle used for handling [[Intermodal container|intermodal cargo container]]s in small terminals or medium-sized ports. Reach stackers are able to transport a container short distances very quickly and pile them in various rows depending on its access.

==== Sidelifter ==== [[File:Bundesarchiv Bild 183-K0315-0001-026, Leipzig, Frühjahrsmesse, Freigelände, Sattelauflieger, Container.jpg|thumb|Sidelift crane]]

A [[sidelifter]] crane is a road-going [[truck]] or [[semi-trailer]], able to hoist and transport ISO standard [[Intermodal container|containers]]. Container lift is done with parallel crane-like hoists, which can lift a container from the ground or from a [[flatcar|railway vehicle]].

=====Travel lift===== A [[travel lift]] (also called a boat gantry crane, or boat crane) is a crane with two rectangular side panels joined by a single spanning beam at the top of one end. The crane is mobile with four groups of steerable wheels, one on each corner. These cranes allow boats with masts or tall super structures to be removed from the water and transported around docks or marinas.<ref>{{Cite web|url=https://marinetravellift.com/travel-lift/|title=Travel Lift|access-date=1 October 2019|archive-date=30 September 2019|archive-url=https://web.archive.org/web/20190930232745/https://marinetravellift.com/travel-lift/}} and other pages on this Web site.</ref> Not to be confused mechanical device used for transferring a vessel between two levels of water, which is also called a [[boat lift]].

===== Straddle carrier ===== {{main|Straddle carrier}}

[[Image:SISU Valmet 44011 Straddle carrier p5.JPG|thumb|Straddle-carrier]]

A [[Straddle carrier]] moves and stacks [[intermodal container]]s. It operates in a way similar to a gantry crane, but its purpose resembles a pick-and-carry crane, since it is used to move containers from one area to another.

=== Industrial ===

====Ring{{anchor|Ring crane}}==== {{See also|Ring crane}} [[File:Mammoet ring crane (51516326449) (crop to crane).jpg|thumb|[[Ring crane]]]]

[[Ring crane]]s are some of the largest and heaviest land-based cranes ever designed. A ring-shaped track support the main superstructure allowing for extremely heavy loads (up to thousands of tonnes).

====Hammerhead==== [[File:Wfm crane north rotunda.jpg|thumb|upright=1.5|Hammerhead crane ([[Finnieston Crane]]) in [[Glasgow]]]]

The "hammerhead", or giant [[cantilever]], crane is a fixed-[[jib (crane)|jib]] crane consisting of a steel-braced tower on which revolves a large, horizontal, double [[cantilever]]; the forward part of this cantilever or [[jib (crane)|jib]] carries the lifting trolley, the jib is extended backwards in order to form a support for the machinery and counterbalancing weight. In addition to the motions of lifting and revolving, there is provided a so-called "racking" motion, by which the lifting trolley, with the load suspended, can be moved in and out along the jib without altering the level of the load. Such horizontal movement of the load is a marked feature of later crane design.{{sfn|Pitt|1911|p=370}} These cranes are generally constructed in large sizes and can lift up to 350 tons.<ref>{{cite web |url=https://www.bizjournals.com/philadelphia/stories/1996/12/16/story5.html |title=Navy's biggest crane is coming down |date=16 December 1996 |access-date=2024-07-11 }}</ref>

The design of ''Hammerkran'' evolved first in Germany around the turn of the 19th century and was adopted and developed for use in [[United Kingdom|British]] [[shipyard]]s to support the battleship construction program from 1904 to 1914. The ability of the hammerhead crane to lift heavy weights was useful for installing large pieces of [[battleship]]s such as [[Naval armour|armour plate]] and [[gun]] barrels. Giant cantilever cranes were also installed in naval shipyards in [[Japan]] and in the [[United States]]. The British government also installed a giant cantilever crane at the [[Singapore]] Naval Base (1938) and later a copy of the crane was installed at [[HMAS Kuttabul (naval base)|Garden Island Naval Dockyard]] in [[Sydney]] (1951). These cranes provided repair support for the battle fleet operating far from [[Great Britain]].

In the British Empire, the engineering firm [[Sir William Arrol & Co.]] was the principal manufacturer of giant cantilever cranes; the company built a total of fourteen. Among the sixty built in the world, few remain; seven in England and Scotland of about fifteen worldwide.<ref>{{cite web |url=http://freespace.virgin.net/iw.history/cowes/crane.htm |title=The Cowes Giant Cantilever Crane |publisher=Freespace.virgin.net |access-date=2012-08-15 |archive-url=https://web.archive.org/web/20120828070831/http://freespace.virgin.net/iw.history/cowes/crane.htm |archive-date=28 August 2012 }}</ref>

The [[Titan Clydebank]] is one of the four Scottish cranes on the [[River Clyde]] and preserved as a tourist attraction.

====Level luffing==== {{Main|Level luffing crane}}

[[File:Dillingen Kran.jpg|thumb|upright|[[Level luffing crane]]]] Normally a crane with a hinged jib will tend to have its hook also move up and down as the jib moves (or ''luffs''). A [[level luffing crane]] is a crane of this common design, but with an extra mechanism to keep the hook at the same level when the jib is pivoted in or out.

====Overhead==== {{Main|Overhead crane|Electric overhead traveling crane}}

[[File:DCC38974rvancopp.jpg|thumb|upright|An [[overhead crane]] being used in typical machine shop. The [[hoist (device)|hoist]] is operated via a wired pushbutton station to move system and the load in any direction.]]

An [[overhead crane]], also known as a bridge crane, is a type of crane where the hook-and-line mechanism runs along a horizontal beam that itself runs along two widely separated rails. Often it is in a long factory building and runs along rails along the building's two long walls. It is similar to a [[gantry crane]]. Overhead cranes typically consist of either a single beam or a double beam construction. These can be built using typical steel beams or a more complex box girder type. Pictured on the right is a single bridge box girder crane with the [[hoist (device)|hoist]] and system operated with a control pendant. Double girder bridge are more typical when needing heavier capacity systems from 10 tons{{which|date=December 2021}} and above. The advantage of the box girder type configuration results in a system that has a lower deadweight yet a stronger overall system integrity. Also included would be a hoist to lift the items, the bridge, which spans the area covered by the crane, and a trolley to move along the bridge.

The most common overhead crane use is in the [[steel industry]]. At every step of the manufacturing process, until it leaves a factory as a finished product, [[steel]] is handled by an overhead crane. Raw materials are poured into a [[Metallurgical furnace|furnace]] by crane, hot steel is stored for cooling by an overhead crane, the finished coils are lifted and loaded onto [[truck]]s and [[train]]s by overhead crane, and the [[fabrication (metal)|fabricator]] or stamper uses an overhead crane to handle the steel in his factory. The [[automobile]] industry uses overhead cranes for handling of raw materials. Smaller [[workstation]] cranes handle lighter loads in a work-area, such as [[CNC]] mill or saw.

[[File:Submarí Ictineu 3 col·locat sota un pont grua.JPG|thumb|An EOT overhead crane is used to move and build the [[Ictineu 3]] [[submersible]], in a [[warehouse]] of [[Sant Feliu de Llobregat]].]]

Almost all paper mills use bridge cranes for regular maintenance requiring removal of heavy press rolls and other equipment. The bridge cranes are used in the initial construction of paper machines because they facilitate installation of the heavy cast iron paper drying drums and other massive equipment, some weighing as much as 70 tons.

In many instances the cost of a bridge crane can be largely offset with savings from not renting mobile cranes in the construction of a facility that uses a lot of heavy process equipment.

This [[electric overhead traveling crane]] is most common type of overhead crane, found in many factories. These cranes are electrically operated by a control pendant, radio/IR remote pendant, or from an operator cabin attached to the crane. {{clear}}

====Gantry==== {{main|Gantry crane}}

{{Further|Container crane}} [[File:Hamburg.CTA.Altenwerder.BungaRaya.wmt.jpg|thumb|[[Gantry crane]]]] [[File:Maschine zum Übersetzen der Diligencen auf Eisenbahnwaggons.JPG|thumb|150px|A gantry crane to put a [[stagecoach]] on a [[flat car]]|left]]

A gantry crane has a [[hoist (device)|hoist]] in a fixed machinery house or on a trolley that runs horizontally along rails, usually fitted on a single beam (mono-girder) or two beams (twin-girder). The crane frame is supported on a gantry system with equalized beams and wheels that run on the gantry rail, usually perpendicular to the trolley travel direction. These cranes come in all sizes, and some can move very heavy loads, particularly the extremely large examples used in shipyards or industrial installations. A special version is the [[container crane]] (or "Portainer" crane, named by the first manufacturer), designed for loading and unloading ship-borne containers at a port.

Most [[container crane]]s are of this type. {{clear}}

==== Jib ==== [[File:Pedestal Jib.jpg|thumb|upright=0.6|Jib crane]]

A jib crane is a type of crane - not to be confused with a crane rigged with a jib to extend its main boom - where a horizontal member (''jib'' or ''boom''), supporting a moveable hoist, is fixed to a wall or to a floor-mounted pillar. Jib cranes are used in industrial premises and on military vehicles. The jib may swing through an arc, to give additional lateral movement, or be fixed. Similar cranes, often known simply as hoists, were fitted on the top floor of warehouse buildings to enable goods to be lifted to all floors.

====Bulk-handling==== [[File:SSA40588hafen.JPG|thumb|Bulk-handling crane]]

[[Bulk-handling crane]]s are designed from the outset to carry a shell grab or bucket, rather than using a hook and a sling. They are used for bulk cargoes, such as coal, minerals, scrap metal etc.

====Stacker==== [[File:Automated Storage and Retrieval System - Defense Visual Information Center · DD-ST-96-00253.JPEG|thumb|upright=0.6|Stacker crane]]

A crane with a forklift type mechanism used in automated (computer-controlled) [[warehouse]]s (known as an [[automated storage and retrieval system]] (AS/RS)). The crane moves on a track in an aisle of the warehouse. The fork can be raised or lowered to any of the levels of a storage rack and can be extended into the rack to store and retrieve the product. The product can in some cases be as large as an [[automobile]]. Stacker cranes are often used in the large freezer warehouses of frozen food manufacturers. This automation avoids requiring forklift drivers to work in below-freezing temperatures every day.

=== Marine === ==== Floating ==== {{Main|Crane vessel}}

[[File:SSCVThialf.jpg|thumb|Floating crane]]

Floating cranes are used mainly in [[bridge]] building and [[port]] construction, but they are also used for occasional loading and unloading of especially heavy or awkward loads on and off ships. Some floating cranes are mounted on [[Pontoon (boat)|pontoons]], others are specialized crane [[barge]]s with a lifting capacity exceeding {{convert|10000|ST|LT t|0|lk=on}} and have been used to transport entire bridge sections. Floating cranes have also been used to salvage sunken [[ship]]s.

Crane vessels are often used in [[offshore construction]]. The largest revolving cranes can be found on [[SSCV Sleipnir|SSCV ''Sleipnir'']], which has two cranes with a capacity of {{convert|10000|t|ST LT|0|lk=on}} each. For 50 years, the largest such crane was "[[Herman the German (crane vessel)|Herman the German]]" at the [[Long Beach Naval Shipyard]], one of three constructed by [[Nazi Germany]] and captured in the war. The crane was sold to the [[Panama Canal]] in 1996 where it is now known as ''Titan''.<ref>{{cite web |date=28 April 2011 |title=Herman the German |url=http://portoflongbeach.blogspot.com/2011/04/herman-german.html |access-date=27 April 2014}}</ref>

====Deck==== [[File:Caroline Delmas (2).jpg|thumb|Deck crane]]

Deck cranes, also known as shipboard or cargo cranes,<ref>{{Cite web |title=Cargo cranes |url=https://www.wartsila.com/encyclopedia/term/cargo-cranes |access-date=2024-03-16 |website=Wartsila.com |language=en}}</ref> are located on ships and boats, used for cargo operations where no shore unloading facilities are available, raising and lowering loads (such as shellfish dredges and fish nets) into the water, and small boat unloading and retrieval. Most are diesel-hydraulic or electric-hydraulic, supporting an increasingly automated control interface.<ref>{{Cite journal |last1=Cao |first1=Yuchi |last2=Li |first2=Tieshan |date=2024-05-01 |title=Nonlinear antiswing control for shipboard boom cranes with full state constraints |url=https://www.sciencedirect.com/science/article/pii/S0141118724000865 |journal=Applied Ocean Research |volume=146 |article-number=103964 |bibcode=2024AppOR.14603964C |doi=10.1016/j.apor.2024.103964 |issn=0141-1187|url-access=subscription }}</ref>

=== Other types === ==== Railroad ==== {{Main|Crane (railroad)}}

A railroad crane has flanged wheels for use on railroads. The simplest form is a crane mounted on a [[flatcar]]. More capable devices are purpose-built. Different types of crane are used for [[maintenance of way|maintenance work]], recovery operations and freight loading in goods yards and scrap handling facilities.

==== Aerial ==== [[File:CH-54-Skycrane-delivers-dozer-vietnam-oct-1966.jpg|thumb|200px|[[CH-54 Tarhe]] aerial crane]]

[[Aerial crane]]s or "sky cranes" usually are [[helicopter]]s designed to lift large loads. Helicopters are able to travel to and lift in areas that are difficult to reach by conventional cranes. Helicopter cranes are most commonly used to lift loads onto shopping centers and high-rise buildings. They can lift anything within their lifting capacity, such as air conditioning units, cars, boats, swimming pools, etc. They also perform disaster relief after natural disasters for clean-up, and during wild-fires they are able to carry huge buckets of water to extinguish fires.

Some aerial cranes, mostly concepts, have also used lighter-than air aircraft, such as [[airship]]s.

== Efficiency increase of cranes == Lifetime of existing cranes made of welded metal structures can often be extended for many years by after treatment of welds. During development of cranes, load level (lifting load) can be significantly increased by taking into account the IIW recommendations, leading in most cases to an increase of the permissible lifting load and thus to an efficiency increase.<ref>[[International Institute of Welding]] Technology, IIW, published the guideline "Recommendations for the HFMI Treatment" in 2016.</ref>

==Similar machines== [[File:Film Shooting From a Crane.jpg|thumb|upright=0.6|Shooting a film from crane]] The generally accepted definition of a crane is a machine for lifting and moving heavy objects by means of ropes or cables suspended from a movable arm. As such, a lifting machine that does not use cables, or else provides only vertical and not horizontal movement, cannot strictly be called a 'crane'.

Types of crane-like lifting machine include: {{div col|colwidth=23em}} * [[Gin pole]] * [[Block and tackle]] * [[Capstan (nautical)]] * [[Hoist (device)]] * [[Winch]] * [[Windlass]] * [[Cherry picker]] {{div col end}}

More technically advanced types of such lifting machines are often known as "cranes", regardless of the official definition of the term.

==Notable Examples== * [[Finnieston Crane]], a.k.a. the ''Stobcross Crane'' ** [[Category A listed|Category A-listed]] example of a "hammerhead" (cantilever) crane in [[Glasgow]]'s former docks, built by the William Arrol company. ** {{convert|50|m|ft|0|abbr=on}} tall, {{convert|175|t}} capacity, built 1926 * [[Taisun]] ** double bridge crane at [[Yantai]], [[China]]. ** {{convert|20000|t|ST LT|0}} capacity, World Record Holder ** {{convert|133|m|ft|0|abbr=on}} tall, {{convert|120|m|ft|0|abbr=on}} span, lift-height {{convert|80|m|ft|0|abbr=on}} * [[Kockums Crane]] ** shipyard crane formerly at [[Kockums]], [[Sweden]]. ** {{convert|138|m|ft|0|abbr=on}} tall, {{convert|1500|t}} capacity, since moved to [[Ulsan]], [[South Korea]] * [[Samson and Goliath (cranes)]] ** two [[gantry crane]]s at the [[Harland & Wolff]] shipyard in [[Belfast]] built by [[Krupp]] ** ''Goliath'' is {{convert|96|m|ft|0|abbr=on}} tall, ''Samson'' is {{convert|106|m|ft|0|abbr=on}} ** span {{convert|140|m|ft|0|abbr=on}}, lift-height {{convert|70|m|ft|0|abbr=on}}, capacity {{convert|840|t}} each, {{convert|1600|t}} combined * [[Breakwater Crane Railway]] ** self-propelled steam crane that formerly ran the length of the breakwater at [[Douglas, Isle of Man|Douglas]]. ** ran on {{Track gauge|10ft}} gauge track, the broadest in the British Isles * [[Liebherr]] TCC 78000<ref>{{cite web|title=TCC 78000 - Heavy Lift Handling in Rostock, Germany |url=https://www.liebherr.com/en/int/products/maritime-cranes/heavy-lift-handling-in-rostock-germany-tcc-78000/tcc-78000.html|publisher=Liebherr|access-date=26 April 2020}}</ref> ** Heavy-duty gantry crane used for heavy lifting operated in [[Rostock]], [[Germany]]. ** {{convert|1600|t|sigfig=3}} capacity, {{convert|112|m|ft|0|abbr=on}} lift-height

==See also== {{Div col|colwidth=23em}} * [[Accredited Crane Operator Certification]] * [[Banksman]] * [[Cherry picker]] * [[Davit]] * [[Floating sheerleg]] * [[Gantry crane]] * Lifting devices with one, two, and three legs: **[[derrick]] **[[sheers]] **[[gyn]] * [[Heavy equipment operator]] * [[Overhead crane]] * [[Pallet]] * [[Patient lift]] * [[Sidelifter]] * [[Steam shovel]] * [[Taisun]] * [[Telescopic handler]] {{Div col end}}

==References== {{Reflist|30em}}

==Sources== {{Commons category|Cranes (machines)}} {{Wikisource|Philosophical Transactions/Volume 54/The Description of a new and safe Crane, which has four different Powers; invented by Mr. James Ferguson, F. R. S.|The Description of a new and safe Crane, which has four different Powers; invented by Mr. James Ferguson, F. R. S.|nocat=yes}} '''History of cranes''' * {{Citation | doi = 10.2307/630416 | last = Coulton | first = J. J. | title = Lifting in Early Greek Architecture | journal = [[The Journal of Hellenic Studies]] | volume = 94 | year = 1974 | pages = 1–19 | jstor = 630416 | s2cid = 162973494 }} * {{Citation | first1 = Hans-Liudger | last1 = Dienel | first2 = Wolfgang | last2 = Meighörner | title = Der Tretradkran | journal = Publication of the [[Deutsches Museum]] (Technikgeschichte Series) | edition = 2nd | location = München | year = 1997 }} * {{Citation | doi = 10.2307/506969 | last = Lancaster | first = Lynne | title = Building Trajan's Column | journal = [[American Journal of Archaeology]] | volume = 103 | issue = 3 | year = 1999 | pages = 419–439 | jstor = 506969 | s2cid = 192986322 }} * {{Citation | last = Matheus | first = Michael | editor-last = Lindgren | editor-first = Uta|editor-link= Uta Lindgren | contribution = Mittelalterliche Hafenkräne | title = Europäische Technik im Mittelalter. 800 bis 1400. Tradition und Innovation | edition = 4th | year = 1996 | publisher = Gebr. Mann Verlag | location = Berlin | isbn = 3-7861-1748-9 | pages = 345–348 }} * {{Citation | doi = 10.2307/3106635 | last = Matthies | first = Andrea | title = Medieval Treadwheels. Artists' Views of Building Construction | journal = [[Technology and Culture]] | volume = 33 | issue = 3 | year = 1992 | pages = 510–547 | jstor = 3106635 | s2cid = 113201185 }} * {{Citation | last = O'Connor | first = Colin | title = Roman Bridges | publisher = Cambridge University Press | year = 1993 | isbn = 0-521-39326-4 | pages = 47–51 }} * {{EB1911|wstitle=Cranes|volume=7|pages=368–372|first=Walter|last=Pitt}}

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