In mechanical engineering, a higher pair links mechanism is known as a cam and follower mechanism. The cam and follower are machined types of roller or needle bearings designed to work on each other. They come in a vast array of various configurations and they work depending on their applications and final output.
Today you’ll get to know the definition, functions, applications, components, diagrams, types, and working of cam and follower. Remember the mechanism can also be derived as a cam-follower.
What is cam?
A cam is a rotating element that offers reciprocating or oscillating motion to a follower which is an element of the machine by direct contact. A cam can also be said to be a mechanical member used to impart desired motion to a follower by direct contact.
These mechanisms can be used to transform rotary motion into linear to another part. This is why it can serve as a rotating wheel, an electric wheel, or a shaft that strikes a lever’s various points at its circular path.
A cam can be used in a steam hammer as a simple tooth to deliver pulses of power.
What is a follower?
A follower is a rotating or oscillating part of a machine that is moved by the cam’s motion due to direct contact between the two-part. Followers move vertically to the axis of the cam when the cam moves in a reciprocating motion.
The follower is part of a machine that follows the cam that is either oscillating or reciprocating in motion.
In brief, a driver member is a cam, while a driven member is known as a follower. There is always a frame that supports the cam and guides the follower.
Functions of cam and follower
Below are the functions of a cam and follower mechanism in their various applications:
A cam-follower mechanism helps to achieve an even distribution of forces in a single machine component.
With a cylindrical roller in a machine component, spontaneous movement can be obtained. Cam-follower can be used to get varieties of linear motions when applied to a machine.
Due to the fact that the thickness of cam-follower is high compared to bearings, they tend to absorb a higher amount of shock. This helps to increase the mechanical efficiency of a machine component.
In addition, the system serves well on soda machines and aircraft applications, because the mechanism is versatile. It also serves well on a conveyor belt.
Applications of a cam and follower mechanism
Below are the various applications of a cam and follower mechanism:
- Cam-follower is used in an internal combustion engine to open and close the outlet and intake valve using the camshaft.
- Used in a hydraulic system.
- Automated machinery makes good use of the mechanism.
- Printing machines also make good use of a cam-follower mechanism.
- Textile and agricultural equipment contain a cam and follower in them.
- Gear-cutting machinery.
- Automatic lathe machines.
Additionally, cam and follower mechanisms are used by engineers to ensure zero or minimum degree of error is obtained. In the automotive industry, a cam-follower mechanism is used to drive fuel pumps and also controls the valves.
Parts of the cam-follower mechanism
The part of cam-follower can vary due to the fact that there are various types out there. So, below this article, we’ve explained the various types of cam and follower is explained with their various parts mentioned.
However, a cam-follower mechanism is developed by incorporating three members such as a driver member which is known as a cam, a frame that supports the cam and follower, and finally, the driven member known as a follower.
Some terminology of a cam-follower
Cam Profile – It is the surface area where a cam and follower touch.
Base Circle – It is the smallest circle of a cam profile drawn from the center of rotation of the cam.
Trace Point – this point allows the cam profile to be traced.
Pitch Curve – This curve is generated if we assume the cam is fixed and the tracepoint of the follower moves around the cam.
Pressure Angle – It is formed between the normal pitch curve and the line of motion of the follower.
Pitch Point – it’s the point where the pressure angle is maximum.
Pitch Circle – It is the circle that passes through the pitch point.
Prime Circle – This is a circle that is drawn tangentially to the pitch curve and concentric to the base circle.
Diagram of a cam and follower:
Types of cam-follower mechanism
Below are the various types of cam and follower
Types of cam:
Disk or plate cam:
A disk or plate type of cam has no regular contour to transmit a specific motion to the follower.
Cylindrical cams have a groove in their cylindrical surface and the follower is designed to run on the cylindrical surface parallel to the axis of the cylinder.
A translating cam also has a grooved or contoured plate as its follower oscillates in the face of the plate. The motion of the follower is specified by the groove or contour.
A wedge cam has an angled flat regular contour so that a specific motion can be imparted to the follower.
Spiral cams have a half-circular or a spiral shaping grooved contour, allowing it to move in a reciprocating motion. The follower moves vertically to the axis of the cam.
This type of cam lookalike with an asymmetric heart, thus it’s named a heart-shaped cam. It is often used to return shafts to hold the cam to a set position by its pressure from a roller.
Types of follower
Below are the various types of followers suitable for different cam motions:
Knife-edge types of followers are designed with a sharp teeth area that contacts directly with the cam. It’s the simplest design among all of the followers and it cannot be used on applications that work with speed only slow ones, due to its sharp edge.
Roller followers are used in high-speed applications due to their smooth contact with the cam surface. Less wear and tear occur on this type of follower compared to the first one.
These types of looks followers are similar to a flat surface with an irregular cam. It is used when space is limited in the mechanism and for resisting side thrust. This follower is also used on applications where precision is necessary.
The spherical types of followers have a curve, it’s just a modification of a flat-faced follower.
A radial follower is similar to a spherical-faced follower, it has a line of movement that passes through the camshaft. The follower which is in a reciprocating motion has its movement in a line. It has the same diagram as the spherical-faced follower.
In this type of follower, the movement of the axis is not collinear with the cam axis.
Working Principle of Cam and Follower
The working of a cam-follower is less complex and can be easily understood. The mechanism depends on each other to work. This means where is cam there must be followers and vice versa else they are useless.
A cam is a mechanical component that rotates in a circular or eclipse about the minor axis of a follower. It can be explained as a mechanical device that transmits oscillating, reciprocating, or linear motion to a follower.
Cams are usually in an oval shape or an imperfect circle or an eclipse. When an oval-shaped cam is considered by an engineer, that means the movement requires an outer burgee, which is periodic to its locus.
The outer burgee is essential for works that are periodic mechanical. The cam is of two types; Single head and Multiple head cam.
In contrast to followers, it’s a part that inhibits push or pulls from a cam. It’s used to transfer motion to the required machine part. A follower rotates in an oscillating or circular arc.
Watch the video below to learn more about how cam-follower works:
In this article, we’ve seen the definition, functions, applications, components, types, and working of cam and follower.
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