Today’s invention is, I believe, a wholly new application for an established technology.
I’m sick of glasses which are held together using some kind of screw. This is supposed to hold the leg to the eyepiece whilst also providing some frictional resistance -so that the legs are angled inwards and the glasses stay on the face. Of course, this usually fails, when the screw starts to disengage.
The technology required to fix this situation is to injection mould the glasses’ eyepiece and both legs as a single unit. Each leg would join the eyepiece using a ‘living hinge’ (as discussed by some experts here).
It’s really a plastic mechanism which snaps between two stable positions…one ‘closed’, so that the leg would be against the frame and the other open at, say, 80 degrees from the frame, so that just enough pressure would be exerted on the head to hold them in place.
Bistables can be made much more robust and fatigue-resistant than the fine bottletop version indicated in the picture.