Short Answer:

A follower is a mechanical part that moves when it comes in contact with a rotating cam. The motion of the follower depends on the shape of the cam and its own design. Followers are widely used in engines, pumps, and machines to convert rotary motion into linear motion.

There are different types of followers depending on their shape, motion, and the way they contact the cam. Common types include knife-edge follower, roller follower, flat-faced follower, spherical follower, and radial or offset follower. Each type has unique characteristics and is used according to the application requirements.

Detailed Explanation :

Types of Followers

A follower is a vital part of the cam-follower mechanism. It follows the cam profile to produce the desired motion such as reciprocating, oscillating, or uniform motion. The classification of followers can be done in different ways based on shape of contact surface, motion of follower, path of motion, and type of motion of the follower. Each type plays an important role in determining how the cam system functions and transfers motion efficiently.

1. According to the Shape of Contact Surface

The follower can have different contact surfaces where it touches the cam. The shape affects friction, wear, and smoothness of motion.

1. a) Knife-edge Follower:
   This follower has a sharp edge or point in contact with the cam surface. It gives precise motion but suffers from high wear due to the small contact area. It is mainly used in low-speed mechanisms.
2. b) Roller Follower:
   In this type, a roller is used at the contacting end of the follower. The roller reduces friction and wear. It is commonly used in high-speed applications like internal combustion engines and automatic machines.
3. c) Flat-faced Follower:
   It has a flat surface at the point of contact. This type can withstand high loads but causes more friction compared to roller followers. It is often used when space is limited or when a uniform motion is needed.
4. d) Spherical-faced Follower:
   This follower has a curved contact surface. It is used to reduce side thrust and friction that occur in flat-faced followers. It offers smooth operation and better durability.
5. According to the Path of Motion

This classification depends on how the follower moves relative to the cam axis.

1. a) Radial or Translating Follower:
   In this type, the follower moves in a line passing through the center of the camshaft. The motion is purely reciprocating (up and down). This is the most common type used in cam mechanisms.
2. b) Offset Follower:
   Here, the line of motion of the follower is at some distance (offset) from the center of the camshaft. This helps in reducing side thrust and improving smoothness of motion. However, it slightly changes the velocity characteristics.
3. According to the Type of Motion of the Follower

The follower motion can also be classified based on the movement produced by the cam.

1. a) Reciprocating Follower:
   The follower moves up and down in a straight line. This type is used in many engine valve mechanisms.
2. b) Oscillating Follower:
   The follower moves in an angular or swinging motion about a pivot point. This type is used where linear motion is not possible or desired, such as in certain fuel pumps or textile machinery.
3. According to the Speed of the Follower
4. a) Uniform Velocity Follower:
   The follower moves with constant speed. It is used where smooth motion without jerks is important.
5. b) Non-Uniform Velocity Follower:
   Here, the follower’s speed changes depending on the cam profile. It is used in mechanisms requiring variable speed, such as in automatic machines.
6. Special Types of Followers

Some followers are designed for specific functions. Examples include mushroom follower, which has a large flat surface, and roller-tipped flat follower, which combines features of both flat and roller types. These are used to achieve specific performance features like reduced friction or increased contact area.

Conclusion

Followers are essential in converting rotary motion of a cam into linear or oscillating motion. The selection of follower type depends on factors like speed, load, friction, and motion requirement. Roller and flat-faced followers are the most common due to their smooth operation and durability. Each type offers unique advantages, and understanding their differences helps in designing efficient and reliable cam-follower mechanisms used in engines, textile machinery, and automation systems.