Short Answer:

A follower is a mechanical component that moves in response to the motion of a cam. It is an important part of a cam-follower mechanism, where the cam drives the follower to produce a specific motion. The follower may move in a straight line or oscillate depending on the cam’s shape and movement.

Followers are used to transmit motion in various machines like engines, textile machines, and automatic equipment. The motion of the follower depends entirely on the cam profile, which determines the rise, dwell, and return of the follower during each rotation of the cam.

Detailed Explanation:

Follower

A follower is a device or mechanical element that follows the contour of a cam to produce a desired motion. It is the driven part of a cam and follower mechanism. When the cam rotates, its specially shaped surface pushes the follower, causing it to move either in a linear (reciprocating) or oscillating path. The follower’s motion is carefully designed to achieve a specific pattern of movement in mechanical systems.

The cam provides the input motion, and the follower delivers the required output motion. This arrangement is widely used in mechanical systems that need timed or repeated motion, such as engines, automatic machines, and control devices.

Working Principle of Follower

The follower works on the principle of contact motion transfer between the cam and the follower. When the cam rotates, its profile (outer surface) comes into contact with the follower. The change in the cam’s radius at each point causes the follower to move upward or downward, depending on the shape of the cam.

The follower movement can be divided into three stages:

Rise: The follower moves upward as the cam lifts it.
Dwell: The follower remains stationary while the cam rotates but maintains constant height.
Return: The follower comes back to its original position as the cam profile lowers it.

This cycle repeats as the cam continues to rotate, providing smooth and continuous follower motion.

Types of Followers

Followers are classified based on motion, shape of contact, and direction of movement.

According to the Motion of the Follower:
- Reciprocating or Translating Follower:
  Moves in a straight line, either vertically or horizontally. Commonly used in engines.
- Oscillating or Rotating Follower:
  Moves in an angular motion about a fixed point. Used in applications like pumps and valves.
According to the Shape of the Contact Surface:
- Knife-edge Follower:
  Has a sharp edge in contact with the cam. It is simple but causes wear due to high pressure on a small area.
- Roller Follower:
  Has a roller at the contact point to reduce friction. It is the most commonly used type.
- Flat-faced Follower:
  Has a flat contact surface, suitable for high-speed applications.
- Spherical-faced Follower:
  The contact surface is spherical, reducing friction and wear.
According to the Line of Movement:
- Radial Follower:
  The motion of the follower is along the axis passing through the center of the cam.
- Offset Follower:
  The line of movement is offset from the cam center, providing a smoother motion.

Functions of a Follower

The follower performs several important functions in a cam mechanism:

Converts rotary motion of the cam into reciprocating or oscillating motion.
Follows the cam profile to ensure the desired motion of the driven component.
Transfers motion smoothly with minimal loss of energy.
Helps achieve accurate timing in automatic machinery and engines.

Applications of Followers

Followers are found in a wide variety of mechanical systems, such as:

Internal combustion engines:
Followers are used with cams to operate engine valves at the right time.
Textile machinery:
Used to control the movement of threads and needles.
Automatic machines:
Used for packaging, labeling, and assembling processes.
Printing machines:
Helps in maintaining timing and movement of rollers and plates.
Fuel injection systems:
Used for precise and timed injection of fuel in engines.

Materials Used for Followers

Followers are usually made from materials that can withstand friction and wear, such as:

Cast iron
Steel (hardened or alloyed)
Bronze (for smooth operation)
Case-hardened steel with surface treatment for high durability

Lubrication between the cam and follower is also important to reduce wear and ensure smooth motion.

Advantages of Using a Follower

Provides precise and repeatable motion.
Simple mechanical arrangement with reliable operation.
Allows design flexibility in motion control.
Can produce complex motion profiles based on cam design.
Easy to maintain and suitable for automation systems.

Factors Affecting Follower Performance

Several factors influence the performance and lifespan of a follower:

Cam profile shape: Determines motion smoothness.
Friction between surfaces: Affects efficiency and wear.
Operating speed: High speeds require balanced designs to avoid vibration.
Spring force: Ensures continuous contact between cam and follower.
Material quality and lubrication: Reduce wear and increase life span.

Importance of Follower in Cam Mechanism

The follower is a critical part of a cam mechanism. Its design ensures that the follower moves exactly as intended for the required operation. In an engine, for example, the valve must open and close precisely at certain times — this accuracy is achieved through the follower’s correct design and response to the cam’s motion.

Hence, the follower acts as a motion translator between the cam and the output component, ensuring controlled and repetitive motion cycles in mechanical systems.

Conclusion:

A follower is an essential mechanical part that receives motion from a cam and transmits it to another part of a machine. It plays a vital role in controlling the timing and pattern of motion. The type and shape of the follower depend on the application and desired movement. Proper design, material selection, and lubrication ensure its efficient performance. Thus, the follower is a key component in many mechanical and industrial applications where smooth and precise motion is required.