Radial Cam

Radial Cams are one of the most common types of ‘cam’. The ‘radial cam’ is a rotating plate or disc with an outer circumference shaped to produce a required movement (usually linear) to a ‘follower’ which is held against it.

The radial cam may be a simple recognisable shape, such a circle or ellipse, or may be more a complex profile producing variations in the speed and magnitude of the follower movement, moments of 'dwell’ or a 'sudden drop’ - as with the 'snail cam’ shown. The sequence of follower movements is designed using a Displacement Diagram and the cam shaped accordingly.

A 'follower’ may simply be a rod, constrained by guides, to slide up and down in a reciprocating motion, as the cam, which it rests upon, rotates underneath it - i.e. as push-rods of some car engines are driven up and down by the engine camshaft. The ends of the 'follower’ may be flat, round, wedge-shaped or pointed for different service conditions or may terminate with a roller for increased wear resistance.

Followers may also be in the form of a lever and when used against these, the cam generates an oscillatory movement.