Locking device

In a locking device of the type comprising driving members driven by a thumb turn from inside a room and by a key from outside the room, dead bolts brought into engagement with the driving members to advance or retreat to lock or unlock the room, and switches for detecting the advance and retreat of the dead bolts, the improvement wherein said dead bolts are formed by dividing the thickness of a dead bolt into two parts and said driving members are formed by dividing the thickness of a driving member into two parts, said dead bolts being brought into engagement with said driving members to advance or retreat, and one of said driving members is driven by the thumb turn and the other by the key;

• said device further comprising a first engaging means for providing that said driving member driven by the thumb turn is rotated integrally with the other driving member driven by the key only when the key is rotated to lock the room, and a further engaging means for providing rotation of the driving member driven by the key integrally with the other driving member driven by the thumb turn when the room is unlocked after having been locked from the inside by means of said thumb turn.