Pul·ley n.; pl. Pulleys   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.


 Tac·kle n.
 1. Apparatus for raising or lowering heavy weights, consisting of a rope and pulley blocks; sometimes, the rope and attachments, as distinct from the block, in which case the full appratus is referred to as a block and tackle.
 2. Any instruments of action; an apparatus by which an object is moved or operated; gear; as, fishing tackle, hunting tackle; formerly, specifically, weapons. “She to her tackle fell.”
 Note: ☞ In Chaucer, it denotes usually an arrow or arrows.
 3. Naut. The rigging and apparatus of a ship; also, any purchase where more than one block is used.
 Fall and tackle. See the Note under Pulley.
 Fishing tackle. See under Fishing, a.
 Ground tackle Naut., anchors, cables, etc.
 Gun tackle, the apparatus or appliances for hauling cannon in or out.
 Tackle fall, the rope, or rather the end of the rope, of a tackle, to which the power is applied.
 Tack tackle Naut., a small tackle to pull down the tacks of the principal sails.
 Tackle board, Tackle post Ropemaking, a board, frame, or post, at the end of a ropewalk, for supporting the spindels, or whirls, for twisting the yarns.