So what are the differences between compressed springs, extension springs, and torsion springs? How should we distinguish between them?

A compressed spring (compressed spring) is a helical spring that bears axial pressure, and its material cross-section is mostly circular, though rectangular and multi-strand steel configurations are also used. The spring is generally of uniform pitch and can have shapes such as cylindrical, conical, convex, concave, and a small number of non-circular forms. There is a certain gap between the coils of a compressed spring, and when subjected to external loads, the spring compresses and deforms, storing elastic potential energy. The products have a wide range of applications in electronics, motors, computers, information technology, automobiles, bicycles, hardware tools, gifts, toys, and even the defense industry, due to their design and principles being easy to grasp and their manufacturing control being relatively simple.

Extension springs can directly hang heavy objects; they can also be inverted to support a sleeve, with the upper end of the sleeve bearing the weight. Extension springs are used for chest muscle training; nowadays, extension springs are generally dual-function, also usable as grip strengtheners. Arm strengtheners are used to exercise various muscle groups in the arms, and there are many methods of training; the two types of equipment are essentially different. Compressed springs can directly support heavy objects, and can also support a core rod, with the lower end of the core rod hanging weight, such as in mattresses, sofas, lighters, etc., which utilize this characteristic of compressed springs. Torsion springs (torsion springs), leveraging the principle of leverage, create large mechanical energy through the twisting or rotating of flexible and tough elastic materials. They are springs that bear torsional deformations, and their working parts may either be closely wound or loosely wound, such as clips for clothes and small hairpins used in hair accessories.

Compressed springs, torsion springs, and extension springs are all different in shape and form; there is no interchangeability in their installation. Therefore, you can tell which spring to use just by looking at what you need to install.