IMPROVEMENTS RELATING TO SECURITY LOCKS WITH JOINT OPERATION HOOK-SHAPED LOCK BOLTS

摘要

The present invention proposes a security lock comprising regular sliding latches, along with a set of separate hook-shaped latches in the form of curvilinear projections operating jointly in the manner to interlock with suitable latch slots on the door frame. According to the present invention, said curvilinear latches are additionally provided with a plurality of pins vertically projecting from the lateral surfaces of said curvilinear latching means. Those engage into lithe latch slots and keep the latches and thereby the door fixedly joined to the door frame in case of an unauthorized attempt to release the lock by bending the lock panel inwardly so as to let the latches come out of the slots even though the latches are still in their locking positions.