Card operated lock

Abstract

A card operated lock includes a lock box in which an inner card slit opened to the interior of a room and a outer card slit opened to the exterior of the room are disposed in substantially coplanar relationship with each other. A lock card having a predetermined pattern of punched engaging holes is inserted previously into the inner card slit while a key card comprising the same pattern of punched engaging holes as the lock card is inserted into the outer card slit when the lock is unlocked or opened. A plurality of rocking tumblers each of which is substantially in the form of a T-shaped plate are inserted into the lock box in the form of an array extended in the widthwise direction of the key card and perpendicular to the card slits. A horizontal bar portion of each T-shaped rocking tumbler is extended along both the inner and outer card slits. Each T-shaped rocking tumbler is biased in a direction in which a pair of detection projections extended from the horiozntal bar portion of the T-shaped rocking tumbler in symmetric relationship with each other with respect to a vertical bar portion of the T-shaped rocking tumbler are pressed against the lock and key cards inserted in the inner and outer card slits. Each T-shaped tumbler is guided so that it can be displaced over a distance at least equal to the thickness of the card in the direction of thickness thereof and it can be rocked or swung, whereby the punched engaging hole patterns of the lock and key cards are determined to be coincident with each other depending upon whether or not all rocking tumblers are maintained upright.