Door lock security system

Abstract

A door lock security system is disclosed in which each lock in a multiple lock system is modified by the addition of door lock security apparatus which, in electrical form, stores at least an individual key combination (and possibly several different levels of master key combinations) for the lock. Also, the conventional lock cylinder is replaced with a cylinder assembly which senses the magnetic reluctance state (high or low) of predetermined locations on a key substantially resembling a conventional cylinder lock key in size, weight and general shape and capable of mechanically operating the lock. The magnetic reluctance states of the predetermined locations digitally encode the key combination and the thus encoded combination is compared to the electrically stored one, disabling the mechanical operation of the lock unless the two combinations are identical. The electrical combination storage means within the door lock security apparatus may be placed in an adaptive state in which the combination of the next key inserted into the lock is stored as the lock combination and, thereafter, only a key with that combination will operate the lock. There is also provided an emergency key which overrides all other keys and, at any time, can operate any lock in a multiple lock system. This emergency key generates a time varying electrical signal which enables operation of any door lock despite its stored combination.