| 摘要 |
<p>A key blank in which the upper edge surface of the blade has a longitudinal groove dividing that surface into two laterally spaced parts, and a relatively narrow waist is formed in the blade upper portion by progressive narrowing of the blade width downwardly from and adjacent the upper edge surface. The blade is basically a flat parallel sided member and the waisting is created by two substantially symmetrical grooves. Each part of the upper edge surface on each side of the longitudinal groove slopes downwardly and outwardly so as to be substantially normal to the flat sloping surface of the adjacent waisting groove. A key formed from the blank described has bittings cut in the upper edge surface and each bitting is cut on an angle so that the base of each resulting valley part slopes at substantially the same angle as a part of the upper edge surface. Alternate valley base surfaces may slope in opposite directions. A lock having a keyway with a cross sectional shape complimentary to that of the key blank blade described and having two series of pin tumblers arranged angularly relative to one another so that one series is engageable with one upper surface part of the key and the other series is engageable with the other upper surface part of the key. The invention is also directed to a combination of a lock and key described and further to a master keyed system including a plurality of locks and keys.</p> |
