Electric permutation locks

Official title: Electric permutation locks; Circuits therefor {; Mechanical aspects of electronic locks; Mechanical keys therefor (arrangements for sensing or reading record carriers G06K7/00; mechanisms including electronic locks actuated by nonmechanical keys such as passive and active electrical keys and other data carriers G07C9/00, G07F7/00; electronic switching H03K17/00)}

E05B49/00 (Electric permutation locks) appears on 528 US grants and 519 published applications in this corpus.