idle pulley

or idler pulley

noun

, Machinery.

1. a loose pulley made to press or rest on a belt in order to tighten or guide it.

idle pulley

noun

1. a freely rotating trolley used to control the tension or direction of a belt Also calledidler

Word History and Origins

Origin of idle pulley¹

First recorded in 1885–1890

Example Sentences

This serves to drive a belt which, passing over a series of idle pulleys, as will be seen by reference to Figs.

From Project Gutenberg

To maintain equal tension of belt at whatever angle the cutter may be set, the idle pulley b2 acts as a belt tightener, being carried by the rods t and t1.

From Project Gutenberg