Patent ID: 7192016

Claim:
A torsion spring assembly comprising: a movable member pivotally mounted on a base member and movable between first and second angular positions and biased to either one of the first and second angular positions by an overcentre torsion spring which has one end portion anchored to the base member and an other end portion received in an engagement hole in the movable member; the engagement hole being an elongate acute-angle hole comprising a first linear portion and a second linear portion that communicate with one another and form an acute angle therebetween; whereby on initial assembly said other end portion of the torsion spring is placed in the first linear portion of the engagement hole while the spring is in a relaxed condition, and to prime the torsion spring assembly prior to use said other end portion of the torsion spring is moved along the first linear portion of the engagement hole and into the second linear portion accompanied by torsioning of the torsion spring; and a guide member immovably fixed relative to the base member and located to contact said other end portion of the torsion spring to move said other end portion along the first portion of the engagement hole and into the second portion on pivotal movement of the movable member to its second angular position.