Coil spring

A coil spring is a mechanical device that typically is used to store energy and subsequently release it, to absorb shock, or to maintain a force between contacting surfaces. It is made of an <a href="/facts/Elasticity_(physics)/wcJoIFg1">elastic</a> material formed into the shape of a <a href="/facts/Helix/BqC4AKwL">helix</a> that returns to its natural length when unloaded.
Under tension or compression, the material (wire) of a coil spring undergoes torsion. The spring characteristics therefore depend on the <a href="/facts/Shear_modulus/9e9IvJnz">shear modulus</a>.
A coil spring may also be used as a <a href="/facts/Torsion_spring/qMrn3XGM">torsion spring</a>: in this case the spring as a whole is subjected to torsion about its helical axis. The material of the <a href="/facts/Spring_(device)/jknGXzTq">spring</a> is thereby subjected to a <a href="/facts/Bending_moment/6tmafWtR">bending moment</a>, either reducing or increasing the helical radius. In this mode, it is the <a href="/facts/Young%2527s_modulus/MV5JMCIM">Young's modulus</a> of the material that determines the spring characteristics.

Coil spring open-in-new

Coil spring