Clock lock

Abstract

An improved clock lock of the type using an electronic timer circuit as clock mechanism is disclosed. A locking member is actuated toward the unlocked state in response to unlocking signal generated by the electronic timer circuit. The clock lock includes motors adapted to be activated in response to unlocking signal, cams in operative association with the motors, a movable plate normally held in the locked state in the casing to move toward the unlocked state by means of a first cam when any one of the motors starts its rotation, a locking member normally held at the locked position on the movable plate in the casing to turn to the unlocked position by the effect of moment caused by its own dead weight when it is released from the locked state, and a motor driving circuit which is so designed that none of the motors is activated toward the locked state as long as any one of the motors has failed to finish rotation toward the unlocked state by means of microswitches which are in operative association with second cams. Usually, the locking member is designed in the form of an unbalancedly weighted lever. The first cam is preferably designed in the form of a circular cam which is eccentrically mounted on the cam shaft, while each of the second cams is designed in the form of a sector cam. One of the second cams is mounted on the cam shaft at a delayed angle relative to other ones.