Three piece, screwless sheet metal spectacle frame (optional VA/TI/AL) with integrated resilient hinge system and formal integrated clasp

摘要

The hinge connecting side-piece (4) to mounting is based on inherent tension in the metal. It has three lengthways slits at the end of the side-piece to form three free-standing springs (1-3) bent to make up a connecting element. This is joined in tension to a strap (8) on the spectacles frame and remains foldable to provide the hinge function. The two outer springs (1,3) are bent into a U-shape at their ends to grasp the mounting (5) parts (6,7) as compared with the centre spring (2) which is bent out of its original plane so as to fit into the strap slot (8) so that the right-hand side of this forms an end-stop for the side-piece when this is folded out for use. In this position, the two ends of the respective springs give rise to a triangle of tension.