Abstract: A key-switch device has mechanisms for locking an actuating member and devices for switching an electric circuit printed on a board. A specific key for releasing the lock of the actuating member is inserted into a key way in the actuating member, and the switching action of the circuit is effected by means of the key. A notch may be provided with the key for selectively effecting the switching action.

Abstract: A locking device is disclosed which comprises a multi-leaved key which is adapted to be inserted within a correspondingly configured keyhole provided within an inner cylinder member. The inner cylinder member is slidably disposed within an outer cylinder member so as to permit or prevent rotation of the inner cylinder member with respect to the outer cylinder member through the interaction between a projection member and a slot or groove respectively provided upon the inner and outer cylinder members, as well as to permit or prevent the inner cylinder member from being engaged with a cam member which is operatively associated wih a lock bolt.

Abstract: Disclosed is a locking device having an inner lock cylinder axially slidable in a recess in the lock housing. Tumbler means prevent relative motion between the cylinder and the housing until the axial insertion of a key with a double set of notches. Upon insertion thereof, the cylinder may be axially displaced only by pressure against the key to actuate the lock release.