crank, mechanical linkage consisting of a bar attached to a pivot at one of its ends in such a way that it is capable of rotating through a complete circle about the pivot. One of the principal uses of a crank is to turn reciprocating, or back and forth, motion into rotary motion or vice versa. A bell crank is one designed to change the direction of a linear motion.
The Columbia Electronic Encyclopedia, 6th ed. Copyright © 2012, Columbia University Press. All rights reserved.