Tension spring for short, also known as tension spring, is to bear the axial tension of the helical spring, pull spring is generally made of circular section of raw materials. When not bearing the load, between the ring and the ring of the tension spring is generally all and tight no gap. There is a kind of spiral tension spring, which is usually of equal pitch and round section. It can be used for many occasions, such as manufacturing, assembly, experiment, product development and maintenance.

Many different terminal devices or "hooks" are used to secure the source of tension of the spring. A tension spring works the opposite way to a compression spring. The compression spring works in reverse when it is pressed, and the tension spring works in reverse when it is stretched or pulled apart.

When the ends of the spring are pulled apart, the spring tries to pull them back together. Like compression springs, tension springs absorb and store energy. But unlike a compression spring, most tension springs are at the level required, even when no load is applied. This initial tension determines the tight level of coiling of the spring in the absence of any load.