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| :''For the tool used to raise paddle gear on canal locks, see [[Lock_(water_transport)#Windlass ("lock key")|Windlass ("lock key")]]''
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| [[File:Turnbridge Liftbridge RLH.jpg|thumb|[[Turnbridge]] Windlass Lift road bridge over [[Huddersfield Broad Canal]]]]
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| [[File:L-differentialwinde.png|thumb|5x|Differential windlass]]
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| The '''windlass''' is an apparatus for moving heavy weights. Typically, a windlass consists of a horizontal cylinder (barrel), which is rotated by the turn of a crank or belt. A [[winch]] is affixed to one or both ends, and a cable or rope is wound around the winch, pulling a weight attached to the opposite end.
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| ==Uses==
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| *During the [[Middle Ages]] the windlass could be used to raise stones during the construction of large buildings such as in [[Church of St Mary and All Saints, Chesterfield|Chesterfield's Crooked Spire church]].<ref>{{cite web|url=http://www.bbc.co.uk/ahistoryoftheworld/objects/pB9o-yDFQPm4ZiMXxjZfQA |title=Medieval Builders' Windlass |publisher=http://www.bbc.co.uk |accessdate=September 11, 2012}}</ref>
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| *By the [[Late Middle Ages]] most European [[crossbow]]s employed a windlass as a cocking mechanism, which helped to pull heavier crossbows, but were used in England as early as 1215.<ref>{{cite web|url=http://web.mit.edu/21h.416/www/militarytechnology/crossbow.html |title=Engineering the Medieval Achievement-The Crossbow |publisher=http://web.mit.edu |accessdate=September 11, 2012}}</ref>
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| *Windlasses are sometimes used on boats to raise the [[anchor]] as an alternative to a vertical [[capstan (nautical)|capstan]] (see [[anchor windlass]]).
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| *The rod or stick used to tighten a [[Surgical tourniquet|tourniquet]] in surgical procedures is called a windlass.
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| *The handle used to open [[Lock (water transport)|locks]] on the UK's [[Canals of the United Kingdom|inland waterways]] is called a [[Lock (water transport)#Windlass ("lock key")|windlass]].
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| *Windlass can be used to raise water from a [[water well|well]]. The oldest description of a [[Water well|well]] windlass, a rotating wooden rod installed across the mouth of a well, is found in [[Isidore of Seville]]'s (c. 560–636) ''Origenes'' (XX, 15, 1-3).<ref>{{citation | last = Oleson | first = John Peter | author-link = John Peter Oleson | title = Greek and Roman Mechanical Water-lifting Devices. The History of a Technology | place = Dordrecht | publisher = D. Reidel | year = 1984 | pages = 56f. | isbn = 90-277-1693-5}}</ref>
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| *Windlass have also been used in [[gold mining]]. A windlass would be constructed above a shaft which allowed heavy buckets to be hauled up to the surface.<ref>{{cite web|url=http://outbacknsw.com.au/mining%20brief%20history.pdf |title=Albert Goldfields Mining Heritage |publisher=http://outbacknsw.com.au |accessdate=September 11, 2012}}</ref> This process would be used until the shaft got below 40 metres deep when the windlass would be replaced by a 'whip' or a [[Whim (mining)|'whim']].<ref>{{cite web|url=http://www.kidcyber.com.au/topics/goldsearch.htm |title=Searching for Gold |publisher=http://www.kidcyber.com.au |accessdate=September 11, 2012}}</ref>
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| ==Differential windlass==
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| [[File:Comparison_differential_pulley_windlass.svg|thumb|Comparison of a differential pulley or chain hoist (left) and a differential windlass or Chinese windlass (right). The rope of the windlass is depicted as spirals for clarity, but is more likely helices with axes perpendicular to the image.]]
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| In a '''differential windlass''', also called a '''Chinese windlass''',<ref name="Chinese windlass OED">{{OED|Chinese}} {{Registration required}}</ref><ref name="Morris">{{citation|title=Academic Press Dictionary of Science and Technology|page=416|editor1-last=Morris|editor1-first=Christopher|publisher=Gulf Professional Publishing|year=1992|isbn=978-0-12-200400-1}}</ref><ref name="Knight">{{citation|title=The Practical Dictionary of Mechanics|last=Knight|first=Edward H.|publisher=[[Cassell, Petter, Galpin & Co]]|year=1884}} "''Chinese-windlass'', a differential windlass in which the cord winds off one part of the barrel and on to the other."</ref> there are two coaxial drums of different radii ''r'' and ''r{{'}}''. The rope is wound onto one drum while it unwinds from the other, with a [[movable pulley]] hanging in the [[bight (knot)|bight]] between the drums. Since each turn of the crank raises the pulley and attached weight by only
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| <math>\pi(r - r')</math>, very large [[mechanical advantage]]s can be obtained.
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| ==References==
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| {{Reflist}}
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| ==External links==
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| {{Commons category}}
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| {{Wiktionary|windlass}}
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| *[http://www.inquiry.net/OUTDOOR/skills/b-p/windlass.htm Spanish Windlass]
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| [[Category:Sailing rigs and rigging]]
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| [[Category:Mechanisms]]
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