Engaging elements may be included in foot-receiving devices, such as footwear, bindings, clips, or the like. Such elements may include a bimodal spring member movable between two independent stable positions and an arm that moves in response to the bimodal spring member changing between its stable positions....http://www.google.co.uk/patents/US7730639?utm_source=gb-gplus-sharePatent US7730639 - Engaging element useful for securing objects, such as footwear and other foot-receiving devices
