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.
Cam and cam follower mechanisms are often used in mechanical engineering and various machinery, like internal combustion engines. They are also used in automatic lathe machines, diesel fuel pumps, and other repeating machinery and manufacturing applications.
Well, in this reading, we’ll explore what cams and followers are, their applications, functions, parts, diagram types, and how they work. We’ll also explore their advantages and disadvantages.
Let’s begin!
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What is a Cam and Follower?
A cam and follower is a mechanism of a profiled shape that is designed to move a lever or follower. They are mounted on a shaft to convert rotary motion into linear (reciprocating) motion.
In their workings, the cam rotates, causing the follower to rise and fall, which is known as reciprocating motion. Hence, the cam is a reciprocating, oscillating, or rotating body that affects the oscillating or reciprocating motion of the follower.
The design of a cam and follower can depend on the mechanism of the combination of both. The cam may depend on its own motion or the motion of the follower.
Cam Mechanism
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 motion 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.
Cams are also designed to be simple teeth often used to give pulses of power to a steam hammer. This shape can also be used in an eccentric disc, which allows gentle reciprocating motion in the follower.
A cam can be used in a steam hammer as a simple tooth to deliver pulses of power. Also, it is often used in a shaft and rotating wheel like eccentric wheel, and a cylinder with irregular shape
The follower is expected to move smoothly without requiring too much input power. This will aid smooth working of the cam-follower mechanism. This will also prevent the follower from jamming while working. Before the production of inexpensive electronics, cams were used as timers and were widely used to control electrical machines.
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Follower Mechanism
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 parts. 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.
The follower is used to transfer motion to the required machine part as it rotates in a circular arc or oscillates. Followers are in direct contact with the cam to achieve the up-and-down movement. Also, they can be in contact with the surface profile by being spring-loaded. Followers help to achieve complicated output motion, and they can have uniform velocity and uniform acceleration.
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 followers can be used to get varieties of linear motions when applied to a machine.
Due to the fact that the thickness of cam followers 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
Below are the various applications of a cam and follower mechanism:
- A 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.
- Wall clocks.
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.
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Parts and Diagram of Cam and Follower
The part of the 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 cams and followers 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.
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Cam-Follower Terminology
Terms like base circle, prime circle, and pressure angle need to be understood when discussing cam follower mechanisms. Well, below are cam-follower terms you should know:
- 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.
Types of Cams
Below are the various types of cams:
- Disk or Plate cam.
- Cylindrical cam.
- Translating cam.
- Wedge cam.
- Spiral cam.
- Heart-shaped cam.
- Conjugate cam
- Globoidal Cams
- Spherical cam
Disk or plate cams
A disk- or plate-type cam has no regular contour to transmit a specific motion to the follower.
Cylindrical cams
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.
Translating cam:
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.
Wedge cams
A wedge cam has an angled flat regular contour so that a specific motion can be imparted to the follower.
Spiral cams
Spiral cams have a half-circular or spiral-shaped grooved contour, allowing it to move in a reciprocating motion. The follower moves vertically to the axis of the cam.
Heart-shaped Cams
This type of cam looks like 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.
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Conjugate Cams
In a conjugate cam, two discs connect to each other and the axes of the discs are offset by the distance to form a cam profile. The follower has surface contact with a cam profile by two rollers. So as the cam rotates, followers follow it.
Globoidal Cams
These types of cams are designed with a shaft and have a concave or convex circumference. They have a groove made by machining and the groove is used for giving movement to the follower. It is used for oscillating followers about a fixed point.
Spherical Cams
A spherical cam is a spherical shape on which a groove is made and the follower has surface contact with this groove. As the cams, the follower oscillates about a fixed point.
Types of Follower
Below are the various types of followers suitable for different cam motions:
Knife-edge Follower:
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 Follower:
Roller followers are used in high-speed applications due to their smooth contact with the cam surface. Less wear and tear occurs on this type of follower compared to the first one.
Flat-faced Follower:
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.
Spherical Follower:
The spherical types of followers have a curve; it’s just a modification of a flat-faced follower.
Radial 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.
Offset Follower:
In this type of follower, the movement of the axis is not collinear with the cam axis.
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How Does Cam and Follower Work?
The working of a cam-follower is less complex and can be easily understood. The mechanisms depend on each other to work. This means where there is a cam, there must be followers and vice versa; otherwise, they are useless.
A cam is a mechanical component that rotates in a circle or ellipse 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, an imperfect circle or an ellipse. 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 and 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.
Cam and Follower Advantages and Disadvantages
Advantages:
• Converts rotary motion to reciprocating motion.
• Can achieve any desired follower motion.
• Can bear high vibrations.
• Accurate and versatile.
Disadvantages:
• Cam is often subjected to wear and tear.
• High manufacturing cost and precise design.
• Consumes more space.
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Conclusion
The cam and follower mechanism is a fundamental part of many machines, especially in internal combustion engines, automated machinery, and mechanical linkages. It converts rotary motion of the cam into a reciprocating or oscillating motion of the follower.
With various types of cams and followers available, the system can be designed for specific motion profiles, making it versatile in mechanical engineering applications. Proper design, material selection, and maintenance are key to ensuring smooth operation and long life.
FAQs on Cam and Follower
What is a cam and follower?
It is a mechanical system where a cam (rotating part) moves a follower (sliding or oscillating part) to create specific movement patterns.
Where are cam and follower mechanisms used?
- Automobile engines (to operate valves)
- Textile machinery
- Printing presses
- Automation systems
What are the types of followers?
- Knife-edge follower
- Roller follower
- Flat-faced follower
- Spherical-faced follower
What are the types of cams?
- Disk cam
- Cylindrical cam
- Translating cam
- Radial cam
What are the advantages of cam and follower mechanisms?
- Can produce complex motion
- Compact design
- Precise timing in engines
- Suitable for automated machinery
What materials are used for cams and followers?
Typically hardened steel, cast iron, or alloy steel for durability and wear resistance.
What causes cam and follower failure?
- Lack of lubrication
- Wear and fatigue
- Misalignment
- Material defects