Lock with a double locking mechanism for a safe, bank compartment or the like

Claim 1

In a lock with a double locking mechanism, in particular for a bank compartment, comprising a lock casing and first and second mechanisms mounted therein and which can be actuated by a first key and a second key respectively, said first mechanism having at least one tumbler movable by the first key to authorize the operation, by means of the second key, of said second mechanism which comprises at least one bolt associated with a releasable member adapted to co-operate with said tumbler to allow the opening of the lock with the second key, the improvement wherein said lock comprises a link bar (6) pivotally connected (7) to said releasable member (5) which is independent from said bolt (4) and movably mounted with respect to said lock casing (3) so as to enter said tumber (1) after said tumbler has been moved to an appropriate position with respect to said releasable member (5) by means of the first key, said link bar (6) comprises a first end (6a) pivotally connected (8) to said bolt (4) and a second end (6b), a retractable stop member (9) mounted in said lock casing, and means for controlling said stop member between retracted and non-retracted positions from a distance, said stop member co-operating with said second end (6b) of said link bar, so as to authorize the opening of the lock either using the first key and the second key when the stop member is in said non-retracted position or using the second key and upon actuation of said stop member control means to move said stop member to said retracted position.