The tension spring is generally of equal pitch, and the section is mostly circular. When the tension spring (Dongguan tension spring) is not under tension, there is no gap between each coil and each coil, and the connection is very compact. The application range of the extension spring is very wide. In the medical field, it is not only used for respiratory equipment, mobile equipment, motion control, but also for some home care equipment. Mechanical and electronic protection hardware, actuators, and hand tools, as well as some mechanical devices and switching equipment, are also used for the extension spring. The extension spring has a very important meaning for the whole world. The extension spring has irreplaceable effects in the fields of ocean, national defense, wind, railway, aerospace and machinery, elevator, etc. What are the advantages of extension spring? 1. The working principle of the extension spring is just opposite to that of the compression spring. The compression spring has the reverse effect when there is pressure, while the extension spring has the reverse effect when it is stretched. When the extension spring is pulled away, the spring wants to pull back, which generates force. 2. The tension spring can absorb and store energy. The difference between the tension spring and the compression spring is that the initial state of the tension spring determines the tightness of the tension spring under certain tension or without tension. In this way, the control of the initial force can meet the requirements of the unacceptable conditions. 3. The two ends of the extension spring are fixed on other components, and then when these components are separated, the extension spring has an effect. The coils are tightly closed together to produce a strong tensile resistance, which will connect these components together. These spring coils are tightly connected without tension. The closure of the spring includes the hooks hanging on other components, as well as the holes and geometric interfaces. With these fixed on the components that need to be connected, it is not a problem, so when there is tension, it will provide certain resilience for these components.