Extension Springs - Compression Springs - Torsion Springs
Extension springs
The spring is designed to operate with a tension load, so the spring stretches as the load is applied to it.
Compression Springs
Designed to operate with a compression load, so the compression spring gets shorter as the load is applied to it.
Torsion Springs
Unlike the above types in which the load is an axial force, the load applied to a torsion spring is a torque or twisting force