block and tackle

the ropes or chains and blocks used in a hoisting tackle.
[1830-40]

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Combination of pulleys with a rope or cable, commonly used to augment pulling force.

Two or more of the pulleys are attached to a fixed block, and the remaining pulleys are free to move as well as rotate. A block and tackle can be used to lift heavy weights or to exert large forces in any direction. Higher force ratios may be obtained by the use of more pulleys, but this advantage may be offset by increased friction.

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device
 combination of a flexible rope, or cable, and pulleys (pulley) commonly used to augment pulling force; it can be used to lift heavy weights or to exert large forces in any direction. In the Figure—> there are four freely rotating pulleys, two on the upper block, which remains fixed, and two on the lower block, which moves up as the load W is lifted; one end of the rope is anchored to the upper block. If the load W is lifted one foot, each of the four rope links will shorten by one foot so that four feet of rope must be pulled off by the effort F; consequently the force magnification and the mechanical advantage, neglecting friction, is 4. Higher force ratios may be obtained by the use of more pulleys, but this advantage may be offset by increased friction. See also wheel and axle.

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Universalium. 2010.

Look at other dictionaries:

  • block and tackle — Tackle Tac kle (?; sometimes improperly pronounced ?, especially by seamen), n. [OE. takel, akin to LG. & D. takel, Dan. takkel, Sw. tackel; perhaps akin to E. taw, v. t., or to take.] 1. Apparatus for raising or lowering heavy weights,… …   The Collaborative International Dictionary of English

  • block and tackle — ► NOUN ▪ a lifting mechanism consisting of ropes, a pulley block, and a hook …   English terms dictionary

  • block and tackle — n [C usually singular] a piece of equipment with wheels and ropes, used for lifting heavy things …   Dictionary of contemporary English

  • block and tackle — noun count usually singular a piece of equipment that consists of wheels and ropes, used for lifting heavy objects …   Usage of the words and phrases in modern English

  • block and tackle — n. an arrangement of one or more pulley blocks, with rope or cables, providing significant mechanical advantage for pulling or hoisting large, heavy objects …   English World dictionary

  • Block and tackle — A block and tackle [ Tackle can be pronEng|ˈteɪkəl in this usage.] is a system of two or more pulleys with a rope or cable threaded between them, usually used to lift or pull heavy loads. TOC Overview Although used in many situations, they are… …   Wikipedia

  • block and tackle — Pulley Pul ley, n.; pl. {Pulleys}. [F. poulie, perhaps of Teutonic origin (cf. {Poll}, v. t.); but cf. OE. poleine, polive, pulley, LL. polanus, and F. poulain, properly, a colt, fr. L. pullus young animal, foal (cf. {Pullet}, {Foal}). For the… …   The Collaborative International Dictionary of English

  • block and tackle — noun pulley blocks with associated rope or cable • Hypernyms: ↑hoist • Part Meronyms: ↑pulley, ↑pulley block, ↑pulley block, ↑block * * * noun [singular] : a simple machine that is used to help lift heavy objects and that consists of rope and… …   Useful english dictionary

  • block and tackle — UK / US noun [countable, usually singular] Word forms block and tackle : singular block and tackle plural blocks and tackles a piece of equipment that consists of wheels and ropes, used for lifting heavy objects …   English dictionary

  • block and tackle — block′ and tack′le n. bui the ropes or chains and blocks used in a hoisting tackle • Etymology: 1830–40 …   From formal English to slang

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