Springs are useful in various mechanical components and systems as they help provide flexibility and support. They are used in various industries and types of machinery including automotive, aerospace, construction, medical systems, agriculture and electronics. Springs are not built in the same size and shape or with the same material.
Each is designed to meet the needs of a specific machine or application. It’s therefore expedient that you know the different types of springs so you know which suits your specific needs. However, before we talk about the various types of springs, let’s understand what springs are and how they work.
Spring, how it works and it’s uses
A spring is an elastic mechanical device that stores and releases energy when a force is exerted and removed from it respectively. In a normal working condition, a spring will return to its original form when an applied load is taken off.
Springs are mostly used in devices which necessarily have to absorb and store energy for later use. They are particularly built to pull, push, lift, wind, support or protect a device or tool. They come handy in holding a battery in place, absorbing shocks and controlling vibration in machines, lifting engine valves, operating a garage door, retracting a pen, supporting a car frame, etc.
Springs are made with spring steels, a material with high tenacity to restore elasticity. Typical examples of spring materials are Inconel, stainless steel, Titanium, carbon value, ceramic, one-directional glass fiber composite material, steel alloys Rubber/urethane, etc.
Types of springs
Springs come in different types, each built according to the operational needs of a specific application. Let’s take a look at different types of springs.
Helical compression spring
Helical compression springs are designed to resist compression, hence the name. It stores mechanical energy that gets released when a load applied to it is removed. The spring gets shorter as the load becomes heavier but returns to its original form when the load is finally off.
Compression spring is the most common type of spring produced and is particularly built to provide resistance and absorb shock or impact. These types of springs are found in automotive shock absorbers, toys, mattresses as well as retractable pens. Both ends of this elastic spring are flattened to ensure the force is applied inside along the spring.
Helical extension spring
Helical extension springs are the complete opposite of compression springs. It stores mechanical energy when a tension load is applied and releases the energy when the tension is taken off. Unlike compression springs, extension spring resists stretching when pulled. They particularly become longer when a load is applied.
Extension springs feature hooks or loops at both ends which act as attachment points for two components. Helical extension springs are strong and are particularly designed to absorb and store energy as well as provide resistance to a pulling force. You will find them in trampolines, garage doors, carburettors, agricultural equipment, washing machines, etc
Torsion springs
Torsion springs store and release rotational energy when acted upon by a twisting or rotational force. They have a helical shape design with both ends either straight or specially bent to suit the design requirements of a specific application.
Both ends act as an attachment point between two objects, keeping the objects apart. Torsion springs can be found in clothespins, mouse traps, claw-style hair clips, etc. These spring types are so common that when people ask, what are the four types of springs? Torsion springs are always mentioned along with others.
Garter spring
Garter springs have a coiled round shape that creates opposition radially inwardly or outwardly. This spring has both the properties of compression and extension springs, hence is often called compression and extension garter springs. Garter springs because of their power are used around seals that exert much pressure.
They can withstand much strain and can take 30% more stress than the regular compression springs. Garter springs are commonly found in off-road wheel seals, hydraulic pump seals, washing machine seals as well as to maintain pressure seals on shafts.
Coil spring
Coil springs are closed or open-ended mechanical tools that help store potential mechanical power. They are made of metallic or elastic materials and are usually lightweight. While coil springs come in different designs, they are however made by bending a wire strand into a multi-turn helical coil with the help of a CNC coiling machine.
The springs pushed from this machine are however heated to create its springy qualities and perfect its shape. Compression, extension and torsion springs are the three most common types of coil springs. Coil springs are found in components such as garage doors, retractable pens, automobiles, toasters, clocks, toys, mouse traps, trampolines, medical devices, cell phones, etc.
Torsional springs
Torsional springs store and release rotational energy. These springs come with loops at both ends used to attach to mechanical components. When the components turn, the spring stores rotational energy and only releases it when the winding stops.
Spring belt
Spring belts are torsion springs made of metal strings arranged in a belt-like pattern. They are useful in machines or applications where shock absorption or isolation is needed. Invariably reducing stress on the component to which it’s fitted which in turn enhances longevity of the system.
Spring belts have a hook or loop at both ends serving as an attachment point to the component they are fitted to. Just like every torsion spring, it reacts when a rotational force is applied. You will find them in automotive suspension or as buffers in machinery.
Leaf spring
Leaf spring is a type of compression spring built with flat metal springs also called leaves. It is made by placing metal leaves of similar curves on top of each other in order of their length, with the longest usually at the bottom.
The metallic plates are then bolted or clamped together to hold them in place, providing support, stability and flexibility. Leaf springs are best suited for heavy-duty applications as they can withstand heavy loads. You will find them in trucks, trailers, SUVs and agricultural machinery.
Oil seal spring
Oil seal springs are used on oil seals to serve as a radial load device, putting constant pressure on the seal lips against the shaft. Which invariably keeps the seals tighter. Aside from oil seals, oil seal springs are also found in belt-driven motors, shaft seals, and electrical connectors.
Magazine spring
The Magazine spring is a compression type of spring made with an oval or regular coil.
These springs are needed in situations where durability is needed but space is small. These springs store energy and release constant pressure in the components they are fitted to. Making them a good fit in surroundings where constant use and stress are needed.
Magazine springs are used in various components ranging from firearms, electronics, safety devices and industrial machinery. For example, in firearms, magazine springs are placed inside the magazine of a firearm to ensure the consistency and smooth operation of the firearm by providing the pressure needed to push rounds out of the magazine.
In safety devices like airbags, they provide a constant force to ensure these devices function effectively. In small electronics like digital cameras, magazine springs help in resetting the shutter button after each shot, preparing for the next shot.
Conical springs
Conical springs also called tapered springs are compression springs coiled in increasing or decreasing outer diameter, giving it a cone shape. They are needed in application where force increases gradually.
You would find them in several types of contact such as battery contacts and push buttons. They are also used in fire arms and several automotive suspension systems.
Concave springs
Concave springs look and function like hourglass springs, hence are also called hourglass springs. This spring’s center diameter is narrower than the diameter of both ends. However, unlike hourglass spring coils spaced closely, concave coils are further away from each other.
Concave springs are useful in environments where there is limited space.
They are used in the automobile, production, mechanical, engineering and other industries.
Volute springs
Volute spring, also called conical spring, is a compression spring built with flat metals coiled into the form of a cone. During compression, each coil slides over each other enabling the spring to be compressed into a very short length compared to the regular compression spring.
This type of spring has a high compressive force compared to other springs of the same size. Hence, they come very handy in surroundings where a lot of compression force is needed but with limited space.
Volute springs are powerful, hence, can work for long without wearing out. There are two types of volute springs—Single volute springs and double volute springs used in garden pruning spears, railway cars, Sherman tanks, etc.
Straight coil springs
Straight coil springs are compression springs with a constant force pattern that is linear. All the coils in a straight coil spring are of the same diameter. In environments where stability and reliability are needed, straight coil springs are crucial because of their ability to absorb shock between contacting surfaces.
They are commonly used in automotive suspension, motors, industrial machines, electronic devices and other household appliances
Barrel springs
Barrel springs are compression springs with a larger center diameter and a smaller diameter on both ends. Due to their form, barrel springs are usually flexible and occupy smaller space, which in turn helps them prevent buckling.
Because a barrel spring is wider at the center, strain enters differently, allowing for more balance. They are used in diverse industries including the automotive, aerospace, agriculture, marine, toys, furniture, etc.
Hourglass shaped spring
Hourglass-shaped springs are compression springs with a smaller diameter in the center and a larger diameter at both ends. This kind of spring has a high load capacity and therefore comes handy in applications that need high opposition, lateral stability and low solid height.
They are mostly used in automobiles and consumer goods. The railway industry also use them in making locomotives, metro trains and freight cars.
Variable pitch spring
A variable pitch spring is a compression spring with irregular coil spacing. Here, the springs in some places are spaced closely while spaced widely in other places.
They are used in applications where manufacturers want the rate at which shock is absorbed to be controlled in response to the load applied.
With coil and wire diameter steady, the springs spaced widely need more force to compress. Variable pitch springs are found in applications such as commercial and high-end vehicle suspension, high-end mattresses, valves, etc.
Classification of springs
One of the most common questions often asked after knowing what is spring and its uses is, how many different springs are there? The types of springs out there are inexhaustible because each kind of spring is produced for specific applications or devices. Springs are however grouped in different categories. So how are spring classified? Springs are classified into three main categories
Based on the load application
This entails how the spring reacts when a load is applied. Here, you have, compression, extension and torsion springs.
Based on displacement due to load applied
This takes into account the pattern or duration a force travels or is distributed in the spring when a force is applied. Here, you have the constant force, linear and variable rate spring
Based on design/construction
This takes into account the shape, size and kind of material used to construct the spring. Springs in this category include coil, flat, molded and machine springs.
While Its size determines the spaces it can fit into, its shape determines how the spring reacts when a force or pressure is applied. Its production material determines its stability and often plays a huge role in applications that are used. For example, machine springs are best suited for heavy-duty applications.
The simplest ways to differentiate springs
Regardless of the shape, size, material or how a force travels, what truly differentiates springs from each other is how they react when a load is applied. Depending on the type, a spring will either compress, stretch or rotate when acted upon by a force.
Final words
While there are many types of springs, this article has listed the most common ones and applications they are applied in. We have also put into perspective what a spring is and its uses. Knowing the function of these will give you a clear direction of which is best suited for your needs.