idle pulley

or idler pulley


noun Machinery.

a loose pulley made to press or rest on a belt in order to tighten or guide it.
Also called idle wheel.

Origin of idle pulley

First recorded in 1885–1890

British Dictionary definitions for idle pulley

idle pulley

idler pulley


noun

a freely rotating trolley used to control the tension or direction of a belt Also called: idler