US 3,942,345 AGranted

Key operated magnetic tumbler lock

AssigneeJapan Magnetic Lock Co., Ltd.

InventorTakashi Sasahara

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Abstract

A key operated locking device of the type using a coded magnetic key to operate a plurality of correspondingly coded magnetic tumblers. The device serves to selectively lock and unlock relative rotation between inner and outer coaxial cylinders in which the inner cylinder has a keyway disposed therein for receiving the magnetically coded key and also carries a plurality of spring-biased magnetic tumblers which magnetically interact with the key. The outer cylinder is provided with a plurality of detents cooperating with the magnetic tumblers wherein the tumblers are normally spring-biased into engagement with the detents of the outer cylinder and are unlocked therefrom by inserting a properly coded magnetic key into the inner cylinder keyway to withdraw in concert the tumblers from the detents by magnetic attraction. With the key in place the inner cylinder may then be rotated relative to the outer cylinder, while the magnetic attraction continuously maintains the tumblers in a recessed or condition inside the inner cylinder.

In a key operated magnetic tumbler lock of the type including an outer hollow cylinder, an inner cylinder mated for coaxial relative rotation inside said outer cylinder and having an elongate keyway extending substantially parallel to the axis of said inner cylinder, a plurality of magnetic tumbler assemblies carried in said inner cylinder and a corresponding plurality of cooperating detents provided on an inner surface of said outer cylinder for selectively locking and unlocking said relative rotation therebetween, and a key carrying a plurality of magnetic members for insertion in said keyway for magnetically causing the disengagement of said associated magnetic tumbler assemblies and cooperating detents to unlock said cylinders, the improvement comprising:

elongate tumbler receiving guides disposed in said inner cylinder and extended transversely to and in juxtaposition with said keyway;
said magnetic tumbler assemblies each including a magnetic tumbler and biasing spring mounted in individual ones of said tumbler guides for longitudinal slideable reciprocation of said tumblers between a protracted condition engaging said detents and a retracted condition juxtaposed said keyway, said biasing springs continuously urging said tumblers toward said protracted condition, said magnetic tumblers each defining a magnetic polar axis and being disposed with said polar axes substantially longitudinally aligned with the longitudinal dimension of said guides;
said detents being provided on an inner surface of said outer hollow cylinder in cooperating registration with said tumblers in their protracted condition for locking said relative rotation of said cylinders;
and
said members of said key each defining a magnetic polar axis and being oriented such that when said key has been inserted in said keyway said members are disposed with their polar axes in substantial parallel juxtaposition and in polar opposition to the polar axes of said tumblers to slideably withdraw said tumblers to said retracted condition.

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Abstract

Claims9