A cam and follower mechanism is a mechanical system employed to obtain a specific reciprocating movement. Within this system, the follower acts as the reciprocating component, while the cam serves as the rotating component. The cam usually has a sphere, cylinder, or disc design. The movement of the follower is influenced by the motion of the cam. The follower itself is a rod that is connected to the cam during operation. This article deeply explains the cam and follower mechanism.
What is a Cam Follower?
A cam follower is also called a track follower. The cam is a mechanical part that is internally connected to a cam. It is installed to reduce the chances of errors. These are top link pairs employed to move links periodically or directly.
The cam follower acts as a barrier between the fuel pump and the camshaft that runs the pump. With the passage of time, some types of cam follower models start to wear out until holes appear. Wear can break down small deposits and particles and damage the camshaft and fuel pump.
The combination of cam and follower is most commonly used in pressure control mechanisms, machine tools, IC engines to operate the intake valve and exhaust valve, etc. These are usually made by stamping, milling, or die casting process.
The cam follower contains a built-in shaft. This shaft has a grooved end that permits parts to be bolted directly to metal parts and other surfaces.
What is a Cam?
A cam is a rotating component that delivers vibratory or reciprocating movement to followers through direct contact. It mainly uses to convert the rotary motion into linear motion.
The cam is one of the most important parts of the machine in which a shaft or a rotating electric wheel hits a lever at different points on its circular path. The cams are most commonly used in steam hammers as a simple tooth converting an impulse of power into a steam hammer.
The automobile camshaft is one of the most common examples of the cam, which receives rotary motion by the engine crankshaft and transfers this motion into reciprocating motion to operate the intake valve and exhaust valve.
Types of Cams
The cam has the following major types:
1) According to the shape of the cam
- Snail drop cam
- Wedge or flat cam
- Spherical cam
- Disk or Plate cam
- Spiral cam
- Globoidal cam
- Cylindrical cam
- Heart-shaped cam
- Conjugate cam
- Translating cam
2) According to the follower movement of the cam
- Rise return rise
- Dwell rise return dwell
- Dwell rise dwell return dwell
3) According to the manner of the constraint of the follower
- Preloaded spring cam
- Positive drive cam
- Gravity cam
According to the shape of the Cam
1) Disk or Plate Cam
In these types of cams, the follower has radial motion from the center of rotation of the cam.
These cams have a compact and simple design. You can also install them in a remote location. Therefore, these cams are more famous than other types of cams. These cams are usually used in machine tools and internal combustion engines.
2) Wedge Cam
The wedge cam has a flat, regular shape that is sloped to transfer a particular movement of the follower. This cam is highly dependent on the wedge profile. When the cam rotates horizontally, then the follower also rotates vertically using this guide.
3) Spiral Cam
The spiral cam has a spiral-shaped groove or semi-circular contour in which the cam reciprocates, and the follower oscillates perpendicular to the cam axis.
4) Cylindrical Cam
It contains a groove cut along its cylindrical surface. The rollers follow the grooves, and the follower travels in a plane parallel to the axis of cylinder rotation.
5) Heart-Shaped Cam
These types of cams look very similar to an asymmetric heart. This cam usually uses to return the shaft to maintain the cam in place through the pressure of the rollers.
6) Translating Cams
These types of cams allow the cam to turn in a horizontal direction. It has a contoured or grooved plate. This contoured or grooved plate indicates the follower motion. The follower rotates in front of the plate.
7) Snail Drop Cam
This type of cam is most commonly used in the mechanical chronograph watch so that the daytime advance system works late at night, involving a follower for more than 24 hours in a spiraling path through the cam.
8) Conjugate Cam
These types of cams contain a mechanism with two independently vibrating rollers. The follower acts as a conjugate measurement accessory.
As the cam rotates, a change in the sub-optimal angle between the two follower arms can show a change in cam profile errors.
9) Globoidal Cam
It is a shaft with a convex or concave circumference. The machining process is utilized to create grooves on the cam. The grooves are installed to move the follower. A globoidal cam is installed to swing the follower about a specific point.
10) Spherical Cam
This type of cam has a spherical cam. It has a groove. This groove makes direct contact with the follower. When the cam rotates, the follower swings about a specific point.
Types of Cams According to Follower Motion
1) Dwell Rise Dwell Return Dwell Cam
It depends on the motion of the follower. In this type, the follower moves in such a way that first dwell, rise again dwell, and return and again dwell. The entire process takes place within one cam revolution (360 degrees).
2) Rise Return Rise Cam
It also depends on the motion of the follower. In this cam, the follower moves in such a way that first rises and then returns. The entire process takes place within one cam revolution.
3) Dwell Rise Dwell Cam
In the dwell return rise cam, the motion of the follower is considered. In this type, the follower first dwells, rises, and then again dwells. The whole process takes place within one cam revolution.
Types of Cams According to the Constraint of the Follower
1) Preloaded Spring Cam
This type of cam uses spring force. Compression springs are preloaded into the follower to ensure contact with the surface at all times.
2) Positive Drive Cam
The positive drive cam requires no external force. The follower also doesn’t need external force.
What is Follower
A follower is a vibratory mechanical component that follows the movement of a cam. The follower takes the rotary motion by the cam and changes it into an oscillating or reciprocating motion.
This part of the machine follows the cam motion. The followers may be spring-loaded or may have direct contact with the cam surface.
The follower mechanism and cam mechanism are highly dependent on each other. The cam follower mechanism is most commonly used in different engineering applications and has various characteristics for various applications.
Types of Followers
The follower has the following major types:
1) According to the shape of the follower
- Roller follower
- Spherical follower
- Knife edge follower
- Flat-faced follower
2) According to the movement of the follower
- Oscillating follower
- Reciprocating follower
3) According to the line of movement of the follower
- Radial follower
- Offset Follower
Types According to the Shape of the Followers
1) Roller Follower
These types of followers are mainly used for high-speed processes to maintain smooth contact with the surface. They have low wear and tear issues as compared to other followers.
2) Knife Edge Follower
The knife-edge follower has a sharp edge. This edge makes contact with the cam. It has a simpler design than other followers.
The knife-edge followers aren’t ideal for high-speed applications due to their sharp edges.
3) Flat-faced Followers
These types of followers have a flat surface. This type of cam is employed when you have inadequate space, and this follower can handle more side thrust. These followers usually use in precision applications.
4) Spherical Follower
These types of followers contain a regular or curved follower. It is an improved version of the flat-faced follower.
Types Of Followers According to Movement
The followers have the following types according to the movement:
1) Reciprocating Follower
In the reciprocating follower, the follower reciprocates or acts as a guide as the cam turns. Spherical follower, flat follower, roller follower, and knife-edge follower are the most common examples of reciprocating followers.
2) Oscillatory Motion Type Follower
It has a vibratory movement. This follower is fixed at one point. The cam rotates according to the cam profile, and the follower also oscillates.
Types Of Followers According to The Line of Movement
1) Radial Follower
In the radial followers, the follower line of motion passes through the cam center. The follower moves in a line. It has reciprocating motion.
2) Offset Follower
In this type of follower, the cam center and the follower line of motion don’t lie in the same line.
Working Principle of Cam and Follower
Working of Cam
A cam is a mechanical component that allows a follower to rotate in a vibrating or reciprocating motion. The cam transfers the reciprocating motion to the follower.
The cam has an eclipse, incomplete circle, or oval shape. When you look at an elliptical cam, you can notice the motion that makes a periodic external load at that point. This external load is very beneficial and efficient for regular mechanical work.
The Cam has the following two types of heads:
- Single Head Cam
- Multiple Head Cam
Working of Follower
A follower is a mechanical device that allows a cam to rotate in a circular or oscillatory motion. It stops the cam from being pushed and pulled. The follower takes linear motion by the cam and transfers it to the desired part of the machine.
The cam mechanism and follower mechanism depend on each other. The followers rotate in a circular or oscillating arc.
Cam and follower mechanisms are required for engineering applications and have various features for different machines.
Nomenclature or Terminology of Cam
Following are the terminologies used for cam:
- Prime Circle
- Cam profile
- Pitch circle
- Pitch point
- Base circle
- Pressure angle
- Tracepoint
- Pitch curve
1) Cam Profile
It is the area of the cam surface where the followers meet.
2) Base Circle
The base circle is the smallest circle of the cam profile created by the central rotation of the cam.
3) Pitch Circle
The pitch circle is passed through the pitch point.
4) Prime Circle
The prime circle draws from concentric to the base circle and the tangent to the pitch curve.
5) Pressure Angle
A pressure angle is generated between the line of follower movement and the normal of pitch curve.
6) Pitch Point
This is the point where the pressure angle is maximized.
7) Pitch Curve
The pitch curve is produced by assuming that the cam is fine and the follower’s tracepoints rotate around the cam.
8) Trace Point
You can find the cam profile using track point.
Application Of Cam and Follower
The applications of the cam and follower are given below:
- The cam and follower are most commonly used to operate the inlet and exhaust valves of internal combustion engines.
- They are installed in wall clocks.
- They are installed in the feed mechanism of the automatic lathe machine.
- These are used in screw pieces of machines.
- They use in gear-cutting machinery.
- The cam and follower mechanism is used in hydraulic systems.
- The cam and follower mechanism is employed in textile machines to stitch clothes by a pull and push to move.
- The cam and follower use in different automated parts of the machines.
FAQ Section
What are Cam and Follower?
The cam and follower mechanism is a profile design attached to the shaft that moves the follower or lever. The cam uses to transform rotary motion to reciprocating motion and transfers this motion to the follower. When the cam rotates, the follower moves up and down in a process called reciprocating motion.
What is a Cam Mechanism?
A cam is a rotatory element of a mechanical linkage which uses to convert rotary motion into reciprocating motion. The cams are most commonly used in the rotating wheels (such as eccentric wheels) or shafts that strike the follower at multiple points on the circular path of the cam.
What is the Follower Mechanism?
A follower is a vibratory mechanical component that follows the movement of a cam. A follower is a mechanical device that allows a cam to rotate in a circular or oscillatory motion.
The follower mechanism and cam mechanism are highly dependent on each other. The cam follower mechanism is most commonly used in different engineering applications.
What are the types of the followers?
The followers have the following types:
- Roller follower
- Spherical follower
- Knife edge follower
- Flat-faced follower
- Oscillating follower
- Reciprocating follower
- Radial follower
- Offset Follower
What Are a Cam and Follower Used For?
The cam and follower are most commonly used to properly open and close the intake and exhaust valves of the internal combustion engines. In addition, a cam-follower mechanism is also used to turn fuel pumps in the automotive industry.
What are the types of the cams?
- Snail drop cam
- Wedge or flat cam
- Spherical cam
- Disk or Plate cam
- Spiral cam
- Gravity cam
- Globoidal cam
- Cylindrical cam
- Heart-shaped cam
- Positive drive cam
- Conjugate cam
- Preloaded spring cam
- Translating cam
- Dwell rise dwell return dwell
- Rise return rise
- Dwell rise return dwell