Cylinder lock and key.

摘要

An object of this invention is to provide a key cylinder device (7) which is simple in structure and is able to positively detect the presence or absence of the key (10). In a key cylinder device (7), a key cylinder body incorporates a rotor (9) having a key inserting inlet (9a), and a shutter (23) made of a magnetic material is swingably mounted in the rotor (9) to open and close the key inserting inlet (9a), the shutter (23) being urged by a spring to close the key inserting inlet (9a). When the shutter (23) is held closed, the magnetic force of a permanent magnet (24) acts on a lead switch (25) to turn off the latter. When the shutter (23) is swung open with the key (10) inserted into the key inserting inlet (9a), it covers the permanent magnet (24), thus interrupting the action of the magnetic force of the permanent magnet on the lead switch (25). As a result, the reed switch is turned on.