Torsion Springs

Torsion Springs are the springs that exert a torque or rotary force. When a force is applied to one end of the torsion spring keeping other end fixed, the spring exerts a reverse rotary force to push it back to original position. Generally Torsion Springs are close wound but they can have pitch to reduce friction between the coils.They offer resistance to twist applied force.

Internal Diameter is given when spring has to operate over some mandrel such that it should have sufficient clearance to operate freely.The outer diameter is specified when the spring is required to fit into a circular hole with sufficient exterior clearance to operate freely.