A stretch spring (spring) is a coil spring that carries axial tension. A stretch spring is usually made of a circular section. When not under load, the coils of the tension spring spring are usually all and tight with no clearance. It is used to control the movement of machine parts, store energy and measure the force, etc. It is widely used in equipment and instruments. The hook forms have side hook tension spring, long hook tension spring, English hook tension spring, German hook tension spring, half circle hook tension spring, duck mouth hook tension spring and so on, its materials have stainless steel, qin steel, high carbon steel, phosphor copper, oil tempering alloy spring steel.

The "hook" is used to ensure that the tension source of the stretch spring, most of the stretch spring generally under the necessary degree of tension, even in the absence of any load. This initial tension determines how tightly the spring will be wound without any load.

Stretch springs, also known as helical stretch springs, are usually of the same pitch and the sections are mostly round. They can be used for many occasions, such as production and assembly, experiment, research and development, maintenance, etc. Tension spring occupies a key influence in the global market, widely used in computer, electronics, automobile, mold, medicine, biochemistry, engineering 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.