For the tool used to raise paddle gear on canal locks, see Windlass ("lock key")
Turnbridge Windlass Lift road bridge over Huddersfield Broad Canal
Differential windlass

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. 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 (fl. 1290–1333).[1]


Differential windlass

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.

In a differential windlass, also called a Chinese windlass,[8][9][10] 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 between the drums. Since each turn of the crank raises the pulley and attached weight by only , very large mechanical advantages can be obtained.

See also


  1. Needham, Joseph (1986). Science and Civilisation in China. Part 2, Mechanical Engineering. 4, Physics and Physical Technology. Taipei: Caves Books, Ltd.
  2. Hartenberg, Richard; Danavit, Jacques (1964). "Kinematic Synthesis of linkages". McGraw-Hill.
  3. "Medieval Builders' Windlass". BBC. Retrieved September 11, 2012.
  4. "Engineering the Medieval Achievement-The Crossbow". MIT. Retrieved September 11, 2012.
  5. Oleson, John Peter (1984), Greek and Roman Mechanical Water-lifting Devices. The History of a Technology, Dordrecht: D. Reidel, p. 56, ISBN 90-277-1693-5
  6. "Albert Goldfields Mining Heritage" (PDF). Outback NSW. Retrieved September 11, 2012.
  7. "Searching for Gold". Kidcyber. Retrieved September 11, 2012.
  8. "Chinese". Oxford English Dictionary (3rd ed.). Oxford University Press. September 2005. (Subscription or UK public library membership required.) (registration required)
  9. Morris, Christopher, ed. (1992), Academic Press Dictionary of Science and Technology, Gulf Professional Publishing, p. 416, ISBN 978-0-12-200400-1
  10. 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."
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