Electrically activated security door-lock for multi-storey use

摘要

An electrically activated security door-lock (1) eg. for the outer door (17) of a multi-storey building incorporates a modified electromagnetic sequence which ensures that after each electrically operated release of the door, the latch (not shown) and bolt (2) elements of the lock are returned to their engaged position. Automatic opening and closing procedures corresponding to the withdrawal/engagement of the bolt (2) are controlled by tractive electromagnets (5b), delay switches (26), relays and tension/compression springs (6) together with acoustic or visual (30) indication of state.