Adjacent Words

Pulley definitions

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Webster's 1828 Dictionary

PULL'EY, n. plu. pulleys. [L. polus; Gr. to turn.]
A small wheel turning on a pin in a block, with a furrow or groove in which runs the rope that turns it.
The pulley is one of the mechanical powers. The word is used also in the general sense of tackle, to denote all parts of the machine for raising weights, of which the pulley forms a part.

WordNet (r) 3.0 (2005)

n
1: a simple machine consisting of a wheel with a groove in which a rope can run to change the direction or point of application of a force applied to the rope [syn: pulley, pulley-block, pulley block, block]

Merriam Webster's

noun (plural pulleys) Etymology: Middle English poley, pully, from Anglo-French pulie, probably ultimately from Greek polos axis, pole — more at pole Date: 14th century 1. a sheave or small wheel with a grooved rim and with or without the block in which it runs used singly with a rope or chain to change the direction and point of application of a pulling force and in various combinations to increase the applied force especially for lifting weights 2. a pulley or pulleys with ropes to form a tackle that constitutes one of the simple machines 3. a wheel used to transmit power by means of a band, belt, cord, rope, or chain passing over its rim

Britannica Concise

In mechanics, a wheel that carries a flexible rope, cord, cable, chain, or belt on its rim. Pulleys are used singly or in combination to transmit energy and motion. In belt drives, pulleys are attached to shafts at their axes, and power is transmitted between the shafts by means of endless belts running over the pulleys. One or more independently rotating pulleys can be used to gain mechanical advantage, especially for lifting weights. The shafts around which the pulleys turn may attach them to frames or blocks, and a combination of pulleys, blocks, and rope is called a block and tackle. The pulley is considered one of the five simple machines.

Oxford Reference Dictionary

n. & v. --n. (pl. -eys) 1 a grooved wheel or set of wheels for a cord etc. to pass over, set in a block and used for changing the direction of a force. 2 a wheel or drum fixed on a shaft and turned by a belt, used esp. to increase speed or power. --v.tr. (-eys, -eyed) 1 hoist or work with a pulley. 2 provide with a pulley. Etymology: ME f. OF polie prob. ult. f. med. Gk polidion (unrecorded) pivot, dimin. of polos POLE(2)

Webster's 1913 Dictionary

Pulley Pul"ley, b. t. To raise or lift by means of a pulley. [R.] --Howell.

Webster's 1913 Dictionary

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 change of sense, cf. F. poutre beam, originally, a filly, and E. easel.] (Mach.) A wheel with a broad rim, or grooved rim, for transmitting power from, or imparting power to, the different parts of machinery, or for changing the direction of motion, by means of a belt, cord, rope, or chain. Note: The pulley, as one of the mechanical powers, consists, in its simplest form, of a grooved wheel, called a sheave, turning within a movable frame or block, by means of a cord or rope attached at one end to a fixed point. The force, acting on the free end of the rope, is thus doubled, but can move the load through only half the space traversed by itself. The rope may also pass over a sheave in another block that is fixed. The end of the rope may be fastened to the movable block, instead of a fixed point, with an additional gain of power, and using either one or two sheaves in the fixed block. Other sheaves may be added, and the power multiplied accordingly. Such an apparatus is called by workmen a block and tackle, or a fall and tackle. See Block. A single fixed pulley gives no increase of power, but serves simply for changing the direction of motion. Band pulley, or Belt pulley, a pulley with a broad face for transmitting power between revolving shafts by means of a belt, or for guiding a belt. Cone pulley. See Cone pulley. Conical pulley, one of a pair of belt pulleys, each in the shape of a truncated cone, for varying velocities. Fast pulley, a pulley firmly attached upon a shaft. Loose pulley, a pulley loose on a shaft, to interrupt the transmission of motion in machinery. See Fast and loose pulleys, under Fast. Parting pulley, a belt pulley made in semicircular halves, which can be bolted together, to facilitate application to, or removal from, a shaft. Pulley block. Same as Block, n. 6. Pulley stile (Arch.), the upright of the window frame into which a pulley is fixed and along which the sash slides. Split pulley, a parting pulley.

Collin's Cobuild Dictionary

(pulleys) A pulley is a device consisting of a wheel over which a rope or chain is pulled in order to lift heavy objects. N-COUNT