A spring is a mechanical part that USES elasticity to work. The parts made of elastic materials are deformed under the action of external forces, and then recover to their original state after removing the external forces. Also known as "spring". Usually made of spring steel. The kind of spring is complex and diverse, according to the shape, mainly has the spiral spring, the coil spring, the plate spring, the shaped spring and so on.

Spring is just an accumulator, it has the function of storing energy, but can not slowly release the energy, to achieve the slow release of this function should rely on the "spring + large transmission ratio mechanism" to achieve, often seen in mechanical table.

A spring for a watch made on this principle was also invented by hook himself. A spring that conforms to hook's law is a spring in the true sense of the word. The disc spring was invented by the Frenchman belleville. It is a truncated tapered gasket spring made of metal sheet or forged blank.

Spring is made of steel, spring steel's main performance requirements are high strength and high yield limit and fatigue limit, so spring steel with a higher carbon content. But the hardenability of carbon steel is poor, so in the spring with a large section must use alloy steel.

Spring as an important component in the industrial system, there is a large amount of use, and a wide variety of spring, so the production of the original manual production, gradually toward automation.