Mechanical Spring 6 Types, Functions, Materials, Apps, Pros & Cons [PDF]

In this article, we shall learn about the Mechanical Spring which is under the Strength of Material subject covering the types, functions, materials, applications, advantages, and disadvantages of a Spring. We have also provided a PDF for the same.

What is Mechanical Spring

A Mechanical Spring is a device that can also be defined as an elastic or resilient member, whose main function is to deflect under the action of load and recovers it’s original shape when the load is removed. It also used for storing energy.

Types of Mechanical Springs

Mechanical Springs can be classified into various types which are as follows

• Helical Spring
• Conical and volute Spring
• Torsion Spring
• Laminated or leaf Spring
• Disc or Belleville Spring
• Special Purpose Spring

Helical Spring

A helical spring is one type of torsion spring that is made of wire coiled and form a helix shape. It is one of the most used mechanical springs. The cross-section of the wire by which Helical Spring is made can be circular, rectangle, or square in shape. 

In this type of spring, the spring can store the energy when it is pressed and released the stored energy later on, as well as it can withstand the pulling force between two objects. This type of spring can also resist or absorb sudden jerks or impacts. In practice, if you see the suspension of a motorcycle or a high-end railway coach, there you can see helical springs are used. Other than this, helical springs are used for carrying, pulling, or compressing any loads. 

Some of the properties of Helical Springs are as following

• It is durable.
• Higher dimension stability
• High tensile strength
• Corrosion-resistant.

Helical Spring can be categorized as follows

• Closed Coil Helical Spring
• Open Coil Helical Spring

Closed Coil Helical Spring

In a closed coil helical spring, the distance between each turn or coil is pretty less, or you can say the pitch distance is too small. The angle of the helix of the closed coil helical spring is less than 10 degrees. This type of spring is used to resist elongation or twisting. The stiffness of closed coil helical spring is generally higher than any other spring, for this reason, it is used in heavy-duty applications. 

Open Coil Helical Spring

As the name denotes an open coil, that means the distance between two consecutive turns is more (the Helix angle is greater than 10 degrees). These springs are used to resist compression. Generally, open-coil helical springs are used in automobiles, Motorcycles, and even V/Vs assembly of IC engines.

Conical and Volute Spring

This is generally one type of compression spring, conical in shape. When the compression load applies to the spring, then the coils slide over each other, making it short in length and more compact in shape than other helical springs. This type of spring is used in electrical or electronic equipment, garden secateurs, etc. In practical life, you can see this type of spring in the remote or clock’s battery section. This type of spring is also known as tapered spring.

torsion Springs

A torsion spring is one kind of close coil helical spring. In this type of spring, when twisting occurs then the spring stores the energy inside it, and when the twisting force lifts it pushes back to its actual position. When it is twisted a torque is generated in the opposite direction of the twisting force, which helps the spring to back its actual shape.

According to studies, a torsion spring can have a life cycle of 7-9 years, assuming 10,000 cycles at 4 cycles a day. Torsion springs are widely used in garage doors, clips, mouse catchers, torsion bar suspensions, etc. 

Leaf springs 

It is an arc-shaped spring, made of metal strips one after another and held together by using a nut and bolt or clamp. It is widely used as a suspension system for commercial vehicles such as buses, trucks, etc. This spring is capable to withstand large forces in small areas. It is generally made of Steel, Graphite epoxy, and Carbon epoxy.

Disc Springs

Disc or Belleville spring is a conical shape washer held together by a bolt or tube which has the characteristic of spring. It is a non-flat, conical shell spring that generally loads axially. This type of spring can exert constant pressure throughout the object and also provides a high load in small areas. It can be used where thermal expansion or contraction happens rapidly.

Special Purpose Springs

Air spring, gas spring, extension Spring, grater spring, etc. falls under the category of Special Purpose Springs. As the name denotes “Special Purpose” that means these springs are not widely used, but still in some cases like vice-grip pliers, carburetors, trampolines, washing devices, and even in toys we use extension springs. Nowadays we use air springs, where the air is used to pump the bladder which helps us to absorb the shock and vibration completely. So these types of springs are falls under the category of special-purpose springs.

The Function of Mechanical Spring

The Function of Springs are as following

• To absorb the shock or vibration as in-car springs, railway buffers, etc.
• To measure the forces in a spring balance.
• Apply forces in brakes and clutches to stop the vehicles.
• Spring is also used to store energy as in clocks, toys, etc.
• Spring can control the motion of cams and followers by maintaining contact between two elements.

Spring Materials

Springs are made of the following materials

• Hard-drawn wire: These are general purpose springs, where we need low-temperature resistance and low stress we can use these types of spring material.
• Stainless Steel: Nowadays stainless steel is widely used in making springs.
• Phosphor Bronze: These types of springs are used in the Electrical industry due to the material having good electrical conductivity and good resistance to corrosion
• Chrome Silicon: This type of spring can be used in high temperatures up to 250 degrees Celsius.
• Chrome Vanadium: These types of spring have good thermal conductivity up to 220 degrees Celsius and also haves good fatigue resistance.
• Graphite epoxy: It is used in high-strength springs such as leaf springs.
• Carbon epoxy: It is made of carbon fiber and can bear a high load, this material is also used in high-strength applications like automobiles, and locomotives.

Applications of Spring

• Automobile suspension system.
• In cam-follower assembly, we use spring too.
• Spring is used in railway bogies.
• We used spring in the clutch, brake, and valve assembly to exert force on these objects.
• Springs are used in garage doors, gardening equipment, door lock, and many other household accessories.

Advantages of Spring

• Produce a good cushioning effect.
• Spring has a good shock-absorbing ability.
• It has high durability.
• Spring has the ability of stored energy inside it.
• It is easy to design and cheaper to produce.
• Spring is a maintenance-free device.

Disadvantages of Spring

• Day by day its loose it shape and stability.
• Sometimes when the axial load of the spring is increased, it produce the buckling phenomena.
• If spring is broken then it is hard to repair.

Conclusion

In conclusion, mechanical springs come in various types, each designed with specific functions and applications. These springs are crucial components in many industries, providing essential functions such as storing and releasing energy, absorbing shocks, maintaining equilibrium, and transmitting forces.

Different materials, such as steel, alloy, or nonmetal alternatives, are used to suit specific requirements. Mechanical springs offer several advantages, such as cost-effectiveness, durability, and versatility, but they also have limitations, including limited lifespan and susceptibility to fatigue. Overall, understanding the different types, functions, materials, and applications of mechanical springs helps in selecting the appropriate choice for various engineering and manufacturing needs.

References

• NPTEL Courses
• Design and Analysis of a Leaf Spring for automobile suspension system