torsion spring

Torsion springs can store and release angular energy or statically hold a mechanism in place by deflecting the legs about the body centerline axis. They offer resistance to twist or rotationally applied force. A spring of this type will reduce in body diameter and increase slightly in body length when deflected in the preferred direction of the fabricated wind. Depending on the application, torsion springs can be designed to work in a clockwise or counter-clockwise rotation, thus determining the direction of the wind. Common torsion springs are those used in a clothes pin or a garage door.