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 A winch is a mechanical device that is used to pull in (wind up) or let out (wind out) or otherwise adjust the tension of a rope or wire rope (also called "cable" or "wire cable"). In its simplest form, it consists of a spool (or drum) attach ...
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. The Greek scientist Archimedes was the inventor of the windlass. The oldest depiction of a windlass for raising water can be found in the Book of Agriculture published in 1313 by the Chinese official Wang Zhen of the Yuan Dynasty ( 1290–1333).


Uses

*
Vitruvius Vitruvius (; c. 80–70 BC – after c. 15 BC) was a Roman architect and engineer during the 1st century BC, known for his multi-volume work entitled '' De architectura''. He originated the idea that all buildings should have three attribut ...
, a military engineer writing about 28 BC, defined a machine as "a combination of timber fastened together, chiefly efficacious in moving great weights." About a century later,
Hero of Alexandria Hero of Alexandria (; grc-gre, Ἥρων ὁ Ἀλεξανδρεύς, ''Heron ho Alexandreus'', also known as Heron of Alexandria ; 60 AD) was a Greek mathematician and engineer who was active in his native city of Alexandria, Roman Egypt. He ...
summarized the practice of his day by naming the "five
simple machine A simple machine is a mechanical device that changes the direction or magnitude of a force. In general, they can be defined as the simplest mechanisms that use mechanical advantage (also called leverage) to multiply force. Usually the term ref ...
s" for "moving a given weight by a given force" as the lever, windlass, screw for power, wedge, and tackle block (pulley). Until nearly the end of the nineteenth century it was held that these "five mechanical powers" were the building blocks from which all more complex assemblages were constructed.' *During the
Middle Ages In the history of Europe, the Middle Ages or medieval period lasted approximately from the late 5th to the late 15th centuries, similar to the post-classical period of global history. It began with the fall of the Western Roman Empire ...
the windlass was used to raise materials for the construction of buildings such as in Chesterfield's crooked spire church. *A windlass cocking mechanism on
crossbow A crossbow is a ranged weapon using an elastic launching device consisting of a bow-like assembly called a ''prod'', mounted horizontally on a main frame called a ''tiller'', which is hand-held in a similar fashion to the stock of a long fire ...
s was used as early as 1215 in England, and most European crossbows had one by the
Late Middle Ages The Late Middle Ages or Late Medieval Period was the period of European history lasting from AD 1300 to 1500. The Late Middle Ages followed the High Middle Ages and preceded the onset of the early modern period (and in much of Europe, the Renai ...
. *Windlasses are sometimes used on boats to raise the
anchor An anchor is a device, normally made of metal , used to secure a vessel to the bed of a body of water to prevent the craft from drifting due to wind or current. The word derives from Latin ''ancora'', which itself comes from the Greek ἄ ...
as an alternative to a vertical capstan (see anchor windlass). *The handle used to open
locks Lock(s) may refer to: Common meanings *Lock and key, a mechanical device used to secure items of importance *Lock (water navigation), a device for boats to transit between different levels of water, as in a canal Arts and entertainment * ''Lock ...
on the UK's
inland waterways Inland navigation, inland barge transport or inland waterway transport (IWT) is a transport system allowing ships and barges to use inland waterways (such as canals, rivers and lakes). These waterways have inland ports, marinas, quays, and wharfs. ...
is called a windlass. *Windlass can be used to raise water from a
well A well is an excavation or structure created in the ground by digging, driving, or drilling to access liquid resources, usually water. The oldest and most common kind of well is a water well, to access groundwater in underground aquifers. The ...
. The oldest description of a
well A well is an excavation or structure created in the ground by digging, driving, or drilling to access liquid resources, usually water. The oldest and most common kind of well is a water well, to access groundwater in underground aquifers. The ...
windlass, a rotating wooden rod installed across the mouth of a well, is found in Isidore of Seville's ( 560–636) ''Origenes'' (XX, 15, 1–3). *Windlass have also been used in
gold mining Gold mining is the extraction of gold resources by mining. Historically, mining gold from alluvial deposits used manual separation processes, such as gold panning. However, with the expansion of gold mining to ores that are not on the surface, ...
. A windlass would be constructed above a shaft which allowed heavy buckets to be hauled up to the surface. 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'.


Differential windlass

In a differential windlass, also called a Chinese windlass, "''Chinese-windlass'', a differential windlass in which the cord winds off one part of the barrel and on to the other." 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 A pulley is a wheel on an axle or shaft that is designed to support movement and change of direction of a taut cable or belt, or transfer of power between the shaft and cable or belt. In the case of a pulley supported by a frame or shell that d ...
hanging in the
bight The word is derived from Old English ''byht'' (“bend, angle, corner; bay, bight”). In modern English, bight may refer to: * Bight (geography), recess of a coast, bay, or other curved feature * Bight (knot), a curved section, slack part, or loo ...
between the drums. Since each turn of the crank raises the pulley and attached weight by only , very large
mechanical advantage Mechanical advantage is a measure of the force amplification achieved by using a tool, mechanical device or machine system. The device trades off input forces against movement to obtain a desired amplification in the output force. The model for ...
s can be obtained.


Spanish windlass

A Spanish windlass is a device for tightening a rope or cable by twisting it using a stick as a lever. The rope or cable is looped around two points so that it is fixed at either end. The stick is inserted into the loop and twisted, tightening the rope and pulling the two points toward each other. It is commonly used to move a heavy object such as a pipe or a post a short distance. It can be an effective device for pulling cars or cattle out of mud. A Spanish windlass is sometimes used to tighten a
tourniquet A tourniquet is a device that is used to apply pressure to a limb or extremity in order to stop the flow of blood. It may be used in emergencies, in surgery, or in post-operative rehabilitation. A simple tourniquet can be made from a stick an ...
or a straitjacket. A Spanish windlass trap can be used to kill small game. An 1898 report to the US Senate Committee on Foreign Relations about an American vessel captured by a Spanish gunboat described the Spanish windlass as a torture device. One of the captives' wrists were tied together. The captor then twisted a stick in the rope until it tightened and caused the man's wrists to swell.


See also

*
Differential pulley A differential pulley —also called "Weston differential pulley", sometimes "differential hoist", "chain hoist", or colloquially "chain fall"— is used to manually lift very heavy objects like car engines. It is operated by pulling upon the sl ...
*
Hoist (device) A hoist is a device used for lifting or lowering a load by means of a drum or lift-wheel around which rope or chain wraps. It may be manually operated, electrically or pneumatically driven and may use chain, fiber or wire rope as its lifting me ...


References


External links


Spanish windlass
{{Authority control Sailing rigs and rigging Mechanisms (engineering) Winches