cam
n. countablen. a small piece of metal in a machine that turns around. It is shaped in a special way so that it can push another part up and down or back and forth.
n. a rotating or sliding piece in a mechanical linkage used to transform rotary motion into linear motion. Often eccentric or elliptical in shape to provide specific timing for the movement of a follower.
The engine uses a cam to open the valves.
The mechanic noticed that a worn cam was preventing the machine from cycling at the correct speed.
In a traditional internal combustion engine, the profile of each cam determines exactly how long the intake and exhaust valves remain open during the combustion cycle.
Commonly used in mechanical engineering and automotive contexts; often appears in the compound 'camshaft'.