Knife sheath for pivotable knives such that a knife blade is automatically extended as the knife is removed from the sheath. The sheath has front and back faces with connected edges, but having two opposing first and second separated edge areas so that the knife blade may be simultaneously inserted through...http://www.google.fr/patents/US4848000?utm_source=gb-gplus-shareBrevet US4848000 - Sheath for pivotable knives
