1. Field of the Invention
The present invention relates generally to security locks. In particular, the present invention relates to heavy-duty public authority locks, which have a lock bolt that can be manually operated to move from an open position into a closed position and vice versa.
2. Description of the Related Art
A conventional security lock has a blocking mechanism, a lock bolt that interacts with the blocking mechanism, a manually operated drive for operating the lock bolt, and a bolt block. The bolt block has a block position that blocks movement of the lock bolt. The bolt block is a pivotable lever that can be operated by an electric drive. The bolt block has a blocking nose formed on a lock bolt side that engages in a correspondingly formed recess in the lock bolt when the bolt block is in its block position.
The movement of the lock bolt can be blocked in a blocked position by a bolt block. However, it has been found that the bolt block can be released by targeted shaking, which then allows the lock bolt to be opened using the manually operated drive.
There is a need for an improved security lock to overcome this problem.