A tension spring (tension spring) is a helical spring which bears the axial tension. The tension spring is usually made of round section material. In the case of no load, the tension spring ring and ring are usually all tight between no gap. It is widely used in equipment and instruments to control the movement of machine parts, store energy and measure the force by using the elastic force (tension) after stretching. Its hook form has the side hook spring, the long hook spring, the British hook spring, the German hook spring, the semicircle hook spring, the duck bill hook spring and so on, its material has the stainless steel, the qin steel, the high carbon steel, the phosphor copper, the oil tempering alloy spring steel and so on.

The "hook" is used to secure the source of tension for the tensile spring, most of which is usually under the required degree of tension, even when no load is applied. This initial tension determines how tightly the tension spring is wound without any load.

Tensile spring, also known as spiral tensile spring, is usually equal to the pitch, the section is mostly round, they can be used for many occasions, such as production and assembly, experiment, research and development, maintenance, etc. The tension spring has a key influence in the global market and is widely used in computer, electronics, automobile, mold, medicine, biochemistry, construction machinery, mining equipment, construction machinery and other fields. Medical respiratory equipment, motion control, medical mobile equipment, hand tools, home care facilities, shock absorbers, pump springs, mechanical and electronic protective hardware, fluid control valves, mechanical aerospace components, actuators, switching equipment.