What is a cam and follower system?
A cam and follower system is system/mechanism that uses a cam and follower to create a specific motion. The cam is in most cases merely a flat piece of metal that has had an unusual shape or profile machined onto it. This cam is attached to a shaft which enable it to be turned by applying a turning action to the shaft. As the cam rotates it is the profile or shape of the cam that causes the follower to move in a particular way. The movement of the follower is then transmitted to another mechanism or another part of the mechanism.
If we examine the image below we can see how the profile of the cam imparts a particular motion on the follower. In this case the motion is an up and down motion.
Examining the diagram shown above we can see that as some external turning force is applied to the shaft (for example: by motor or by hand) the cam rotates with it. The follower is free to move in the Y plane but is unable to move in the other two so as the lobe of the cam passes the edge of the follower it causes the follower to move up. Then some enternal downward force (usually a spring and gravity)pushes the follower down making it keep contact with the cam. This external force is needed to keep the follower in contact with the cam profile. This is probably best displayed in the animation