Security lock with separate primary and secondary locks - has key operated secondary lock to hold door closed and block access to primary lock

摘要

The primary lock mechanism (12) displaces bolts (10) to lock the door relative to its fixed frame (14), and the secondary mechanism (17) displaces a bolt (18) which blocks the primary bolts in the closure position. The mechanisms (12, 17) may be of the branch type, may be incorporated in a common housing (16) and operate independently under the authorisation of different keys. The primary bolts (10) may project from a horizontally displacing and vertically elongated rectangular slide (11). Key-authorised rotation of the primary lock (12) displaces the slide (11), causing the bolts n10) to enter the frame. The secondary lock (17) may now be activated to move a vertically-displacing secondary bolt (18) into a position where it prevents retraction of the slide (11).