Lock with primary and auxiliary locking mechanisms and corresponding keys

Abstract

A keyway of a hierarchical lock system allows two levels of operation within a hierarchical key system. First level keys have a control rib with a control surface to contact a mating control surface of an auxiliary locking mechanism in a first security level cylinder lock. The control surface extends into a control groove of the keyway defining a secondary portion of the keyway. The first level key also operates a second security level lock with the same keyway, but with no auxiliary locking mechanism, as the first and second security level locks have the same primary locking mechanism—such as tumbler pins—extending into a primary portion of the keyway. The keyways of the first and second security level locks have four sections having at least three different widths, and the first level key has a blade profile defining four segments having at least three different widths and conforming to the profiles of the keyways.