Different Coil Spring Categories and Functions
Springs have revolutionized the way devices work and how we interact with certain products. They have automatized many advanced applications to work adequately with the click of a button or the activation of a switch. Springs form part of many products and they continue to be vital accessories of innovative devices.
When you take a first dive into the wonderful word of springs you will be confronted with all sorts of technical things. From measurements and dimensions to rates and equations but before you get bogged down in details, let's go back to the basics and break down the types of springs you need to know about before you even try to sort out the rest of the details. If you are looking to buy a stock spring the first questions to be asked is what type of spring do you need? Whether you are looking for a stock replacement spring or stock springs for prototyping you first need to know the kind of spring you will search for.
How do you know when a spring can be used to assist in a vital function you need?
There are three main categories of springs. The most common type of spring type are compression springs, followed by extension springs and finally torsion springs. All springs can be useful in different cases but the function they carry out determines when and how they can be used. It is important to understand what a spring does in general. Springs are resilient objects made from coiled wire and they store mechanical energy. The type of spring determines through which action they store and release that mechanical energy
Different Stock Spring Types






Compression Springs
A compression spring is a mechanical device in the shape of a helix made from spring wire. It is used to store or release energy through the action of compressing. It can also absorb shock or maintain a force between two surfaces.
Compression springs are used in a variety of applications from medical industries to toy manufacturing. If you have ever taken apart a retractable ball point pen, you have seen the compression spring that makes it work. Compression springs absorb energy when the coils are pushed together, applying that force at the ends which are usually affixed on one side to a moveable piece. There are characteristic gaps between the coils, called pitch, that the spring collapses into. The closer these spaces come together, and therefore the lower the pitch becomes, the more force is generated by the spring.
There are different subcategories of compression springs such as: conical springs, barrel springs and hourglass springs.
Extension Springs
Helical extension springs are used in devices where a piece is mobilized by a force and needs to return to its original position when the force is taken off. Its hooks allow for it to grab on to your device’s pieces and be pulled/extended.
Extension springs generate force by pulling the ends of the spring (which normally have hooks), away from each other. The further apart the ends are pulled from one another, the greater the force resisting the pull becomes. There are no gaps between the coils in extension springs, meaning that all the coils touch each other, and when force is applied the coils separate as they are streched away from one another.
The types of hooks on an extension spring can vary. The most common type of hook are machine hooks, the second most common are called cross-over hooks, followed by side hooks and lastly extended hooks tend to be the highest priced type of hooks. Some extension springs can also be made with no hooks and be attached by bolts to the application. You can learn more about this here: Extension Springs Without Hooks
Torsion Springs
Torsion springs also known as torque or twist springs are the least common type but quite helpful in the right cirumstance. These springs eject a rotational or torsional force when a load is placed on one or both legs causing them to travel to a desired distance in degrees of deflection.
Torsion springs generate force, or torque, by twisting the spring in such a way that follows the natural direction of wind in that torsion spring. Therefore if you have a left hand torsion spring, rotating one leg clockwise which holding the other one steady should generate resistance. Likewise, a right handed torsion spring would be rotated counterclockwise to generate resistance. A defining characteristic of torsion springs are the two legs protruding from the body of stacked coils. These legs can vary widely in size and are usually affixed to two surfaces, one mobile, one stationary.
Torsion springs are used in different applications, including common every day uses, such as hamper clips, hair clips, clipboards, etc. Here: Torsion Spring Applications you can find out more about torsion springs and the different industries that they are commonly required in.
If you are looking for a spring that facilitates a lifting motion such as that of heavy trailer doors, then torsion springs are most likely what you are looking for. If this is the case you will want to make sure you can measure and look for a torsion spring with the sizes and dimensions that meet your needs. To learn more about torsion springs and how to select and measure them correctly CLICK HERE
In order to determine whether a spring is a good option for the function you want your device to complete, you must first assess what action you require. If you need the spring to release energy stored and create a push back motion you would most likely require a compression spring. If you are looking for a pulling action that extends and retracts you would use an extension spring also known as a tension spring. If what you require is a rotating or radial type of movement, then a torsion spring would tend to be more adequate.