Thewindlass/ˈwɪndləs/ 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. Awinch 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 scientistArchimedes was the inventor of the windlass.[1] A surviving medieval windlass, dated to1360 –1400, is in theChurch of St Mary and All Saints, Chesterfield.[2] The oldest depiction of a windlass for raising water can be found in the Book of Agriculture published in 1313 by the Chinese officialWang Zhen of the Yuan Dynasty (fl. 1290–1333).[3]
Vitruvius, 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 summarized the practice of his day by naming the "fivesimple machines" 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.[4]
Windlass have also been used ingold mining. A windlass would be constructed above a shaft which allowed heavy buckets to be hauled up to the surface.[8] 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".[9]
Comparison of a differential pulley, or chain hoist, at left, and a differential windlass, or Chinese windlass, at right. The rope of the windlass is depicted as spirals for clarity, but it is typically helices with axes perpendicular to the image.
In adifferential windlass, also called aChinese windlass,[10][11][12] there are two coaxial drums of different radiir andr′. The rope is wound onto one drum while it unwinds from the other, with amovable pulley hanging in thebight between the drums. Since each turn of the crank raises the pulley and attached weight by onlyπ(r −r′), very largemechanical advantages can be obtained.
Two Spanish windlasses on a bunch of sticks, in the starting position and tightened
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.[13] A Spanish windlass is sometimes used to tighten atourniquet or astraitjacket. 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.[14] 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.
^Sarton, George (1959). "Part 2, Hellenistic Science and Culture in the Last Three Centuries B. C.".A History of Science. Vol. 2. Harvard University Press, Cambridge. p. 123.
^Oleson, John Peter (1984),Greek and Roman Mechanical Water-lifting Devices. The History of a Technology, Dordrecht: D. Reidel, p. 56,ISBN90-277-1693-5.
^Morris, Christopher, ed. (1992),Academic Press Dictionary of Science and Technology, Gulf Professional Publishing, p. 416,ISBN978-0-12-200400-1
^Knight, Edward H. (1884),The Practical Dictionary of Mechanics,Cassell, Petter, Galpin & Co "Chinese-windlass, a differential windlass in which the cord winds off one part of the barrel and on to the other."
