- a wheel, with a grooved rim for carrying a line, that turns in a frame or block and serves to change the direction of or to transmit force, as when one end of the line is pulled to raise a weight at the other end: one of the simple machines.
- a combination of such wheels in a block, or of such wheels or blocks in a tackle, to increase the force applied.
- a wheel driven by or driving a belt or the like, used to deliver force to a machine, another belt, etc., at a certain speed and torque.
Origin of pulley
Examples from the Web for pulley
So we had to have a pulley system where he was lowered on cables.Rob Reiner on the State of Romcoms, ‘The Princess Bride’s’ Alternate Ending, and the Red Viper
July 27, 2014
Bullock died while attempting to fix one of the presses in 1867: After it became stuck, he tried to kick a belt onto a pulley.The Segway Disaster and Other Deadly Inventions
The Daily Beast
September 27, 2010
Some of these devices are, the wedge, the screw, the pulley and the inclined plane.
In the drawing (A) is the shaft, with a pulley (A), which turns in the direction of the arrow (B).
It is drawn up and let down by a cord passing over a pulley.The Teacher
A pulley over the vat to draw out the rod or net is convenient.Vegetable Dyes
Ethel M. Mairet
The next operation was the reeving of the ropes over the wheels of the pulley.The Plant Hunters
- a wheel with a grooved rim in which a rope, chain, or belt can run in order to change the direction or point of application of a force applied to the rope, etc
- a number of such wheels pivoted in parallel in a block, used to raise heavy loads
- a wheel with a flat, convex, or grooved rim mounted on a shaft and driven by or driving a belt passing around it
Word Origin and History for pulley
late 13c., from Old French polie, pulie "pulley, windlass" (12c.) and directly from Medieval Latin poliva, puliva, probably from Medieval Greek *polidia, plural of *polidion "little pivot," diminutive of Greek polos "pivot, axis" (see pole (n.2)). As a verb from 1590s.
- A machine consisting of a wheel over which a pulled rope or chain runs to change the direction of the pull used for lifting a load. Combinations of two or more pulleys working together reduce the force needed to lift a load. See also block and tackle.