What are the applications of extension spring?

What are the applications of extension spring?

Extension springs are helically coiled wires designed to provide an opposing force when stretched, also named tension springs. springs are stainless steel springs that have two ends to them and attach to another component.

The extension coil springs perform the task of maintaining additional energy and adjustable tension by adding resistance to a heavier force. This resistance controls constant energy in the spring, forcing the spring to pull back after being forced apart. Key specifications include the spring rate, helix type, spring ends type, wire diameter, material, and free and maximum extended lengths.

Extension springs are used in many applications which assist our every-day life. They are easy to miss and extremely under estimated as to the functions they perform and how they are able to make our lives easier. In this article, we will use some examples to illustrate the role that the extension springs used in our daily life.


1. Extension Spring in Chest Expander

The most common exercise equipment you will come across with extension springs is the chest expander. The chest expander works by having a row of extension springs lined side by side and hooked onto a plastic or metal handle at each side. It needs you to pull and resist with your muscles.
Material Wire diameter Outside diameter body length Direction Hardness
stainless steel 0.6mm 13mm 35mm Right HRC 35-38

2. Extension Spring in Refrigerator Door

The spring allows the mullion to fit into a latch on the refrigerator door frame, and lets the door stay closed properly. If you have a damaged spring, your door will not close properly.

3. Extension spring in trampolines

The trampoline has hundreds of hook end extension springs securing the trampoline base to the metal frame.  The extension springs applied in trampolines are all working in parallel so when your weight is applied on the mat, they are extended, but once you jump down on the mat with more force, the energy stored in their coils automatically want to compress back to their original pre-loaded length so they pull on the mat and that’s what cause you to be “thrown” or “ejected” into the air. When the trampoline is at rest, the springs exist at their coiled position.

Material Wire diameter Outside diameter body length Direction Hardness
Spring steel 82B 1.3mm 15mm 114mm Right HRC 40-42

4. Extension spring in washing machine
Extension springs can be applied to washing machines to suspend the drum in position. When the machine spins, the drum revolves at an increased rate. This is where the springs play their role in maintaining the drum in position. Otherwise the machine would bounce around the kitchen with force of the drum banging against the sides.

Material Wire diameter Outside diameter body length Direction Hardness
Alloy steel 14.5mm 88mm 500mm Right HRC 35-38

Applications for extension springs include automotive interiors and exteriors, garage door assemblies, appliances,furniture,engineer machines,washing devices, farm machinery as well as thousands of other uses. We can find extension springs in a variety of everyday items, from garage doors to tools to washing machines to toys.


XULONG SPRING is a professional extension spring supplier and china steel extension spring factory in China, and we have been digging spring field in 1979. If you need any further information, don’t hesitate to contact us !

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