Door unlocking device.

摘要

An object of this invention is to provide a door unlocking device adapted unlock a door by transmitting a signal in the air through a signal transmitter, which can unlock the door even when the power source of the signal transmitter, namely, the battery has consumed up. With a door unlocking device, upon insertion of an ignition key (6) into the rotor (13) of a key cylinder (11), a shutter (14) is opened to operate a shutter switch. Under this condition, the rotor (13) is turned in opposite directions from the neutral position according to a predetermined rotor turning pattern. The rotor turning pattern is discriminated by a rotor-turning-pattern discriminating circuit (10). Ensuring that the rotor turning pattern is the one predetermined for unlocking the door, the rotor-turning-pattern discriminating circuit (18) activates an electric operating mechanism to cause a lock mechanism to unlock the door.