Definition

A cam is a mechanical member used to impart desired motion to follower by direct contact
Cam and follower combination belongs to the category of higher pairs.

What is higher pair

Necessary members of cam and follower mechanism are

A driver member known as cam
A driven member known as follower
A frame which supports the cam and guides the follower
Types of Cams
Cams can be classified according to

Shape
Follower movement
Manner of constraint of the follower
Classifications of Cams according to shape
Wedge and flat cams
Wedge and flat cams

Radial or disc cams
Radial or disc cams

Spiral cams
Spiral cams

Conjugate cams
Conjugate cams

Globoidal cams
Globoidal cams

Spherical cams
Spherical cam

Classifications of Cams according to follower movement

Dwell rise return dwell
Dwell rise dwell return dwell
Classifications of Cams according to constraint of the follower

.
Preloaded spring cams
Positive drive cams
Gravity cam
Types of followers
Cam followers can be classified according to

Shape
Movement and
Location of line of movement
Classifications of followers according to shape
Types of Cam Followers
Knife edge follower
Roller follower
Mushroom (or Spherical) follower
Plate type follower
Classifications of followers according to movement
Reciprocating follower
In this type, as the cam rotates, the follower reciprocates or translates in the guides.

Oscillating follower

The follower is pivoted at a suitable point on the frame and oscillates as the cam makes rotary motion.

Classifications of followers according to line of movement

Radial follower
The follower is known as a radial follower if the line of movement of the follower passes through the centre of rotation of cam.

Offset follower
Offset Follower