The spiral spring generally called clock spring is designed to produce a torque force [circular movement} and appears in two basic models; one with open coils [type A} and one with tight coils [type B]. Type A in working works without friction and is basically used at minor torsion angles. Up to 360ยบ e.g., locking mechanisms Type B is mounted in housing and can be designed to deflect several coils. It has a low force increase and is used for example a drive spring. Normally, this spring is delivered with a locking ring or wrapped by a metal strip.