Spring is only an energy storage device, it has the effect of storing kinetic energy, but can not gradually release the kinetic energy, to complete the release gradually this role should rely on the "spring + large deceleration ratio organization" to complete, more in automatic mechanical watches. Springs have been in use since ancient times, with bows and crossbows being two theoretical types of springs. The actual spring scientist in the strict sense of spring should be the American biologist RobertHooke. Although the shrinking spiral spring had already occurred and been widely used at that time, Hooke clearly proposed "Hooke's law" -- the extension of the spring is positively related to the force it is subjected to. It is exactly according to this principle that in 1776, Spring scale with spiral spring reduction is available. It was not long before Hooke himself invented a special spring for clock applications based on this principle. And in accordance with the "Hook's law" of the spring is really positive in the actual sense of spring. Dish spring is the invention of the American Bele Ye Hill, is made of metal material plate or cast embryo of the truncated cone cross section of the sealing ring spring. After the occurrence of modern industrial production