A coil spring functions by storing energy in order to release it, absorb shock or maintain force between two surfaces. If you apply too much force, you can stretch a spring beyond its limit which will permanently distort the spring.The coil spring has many designs and applications, you can find coil springs in countless everyday products, including: compression spring, tension spring, torsion spring, die spring, V spring. Coil springs can be manufactured in a variety of shapes besides the standard straight coil, including conical, barrel, and hourglass forms which are used in special applications.