US Patent 6880433 Tightening force imparting device

A tightening device includes an energizing member for energizing a tightening member to be secured to a tightening object. The energizing member integrally has at its one end an engaging part to be engaged with the tightening member. A switching member is connected to the tightening member for switching over to the constraining or operating state of the energizing force imparted to the tightening member by the energizing member. The switching member initially tightly holds the engaging part of the energizing member and the other end portion thereof to constrain the energizing force and is then separated from the engaging part and the other end portion of the energizing member to activate the energizing force.