Close Coiled Helical Springs:
A helical spring is composed by winding a wire in the form of a circular cylindrical helix. These can be subjected to axial load or torsional loads. The angle built by the coil with the horizontal is known as helix angle (α). If α is less than 18, this is known close coiled helical springs.
Each coil may be regarded as lying in a plane at right angle to axis of the helix. The wire that creates close coiled helical spring is under torsion.