American Heritage® Dictionary of the English Language, Fourth Edition
- n. A gear, wheel, or roller interposed between two similar parts to convey motion from one to the other without change in speed or direction of motion.
- n. See idle pulley.
Century Dictionary and Cyclopedia
- n. A wheel (C, fig. 1) placed between two others (A and B) for the purpose of transferring the motion from one axis to the other without change of direction; a carrier-wheel. If A and B were in contact, they would revolve in opposite directions; but inconsequence of the intermediate axis of C they revolve in the same direction, and without any change of the velocity-ratio of the pair.
- n. A wheel that performs a duty other than the transmission of power, as the preservation of a strain on a belt, etc. In fig. 2 the small wheel rests upon the belt to maintain its tension, and runs idly, transmitting no power to other parts of the machine.
GNU Webster's 1913
- adj. (Mach.) a gear wheel placed between two others, to transfer motion from one to the other without changing the direction of revolution.
- n. a pulley on a shaft that presses against a guide belt to guide or tighten it
“Sixpence came forward from the idle wheel and watched me veer the chain; then for a quarter of an hour we leaned on the main-boom and watched the crowds upon the shore through field-glasses.”
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