river 40 miles (64 kilometers) E cen England in Cambridgeshire flowing into the Ouse
Machine component that either rotates or reciprocates (moves back and forth) to create a prescribed motion in a contacting element (the follower). Since the shape of the contacting surface of the cam is determined by the prescribed motion and the profile of the follower, cams take various forms. Cam-follower mechanisms are particularly useful when a simple motion of one part of a machine is to be converted to a more complicated prescribed motion of another part, one that must be accurately timed with respect to the simple motion and may include periods of rest (dwells). Cams are essential elements in automatic machine tools, printing machines, sewing machines, and textile machinery.