Patent attributes
A key blank for a cylinder lock comprising a bow 308, a blade longitudinally extending from the bow to a tip, and having a longitudinally extending upper edge 306 to be cut with coded bitting for mating with a tumbler stack of a cylinder lock. A projection 148 extends outwardly on the upper edge adjacent the bow, rising from longitudinally extending surfaces 318 at elevation e0 below the elevation e1 of the upper edge, and having a length parallel to the upper edge that is greater than a width transverse to the edge. The projection is interposed between a front edge portion 306 to be cut with the coded bitting and a back edge portion 310 extending to the bow at elevation e4 above elevation e1. The projection has cam surfaces converging longitudinally and transversely toward a nose 180 at elevation e3 above elevation e1. The back edge 310 has a notch 320 forming an arcuate shoulder spaced from the upper projection at an elevation e2 above elevation e1, to support the rim of an auxiliary pin while the projection is within a recess on the underside of the pin.
