Simultaneously operated dead bolt lock and security chain

Abstract

A dead bolt lock houses both a dead bolt and a security chain assembly. Externally accessible drive linkages cause the simultaneous ejection of the dead bolt and a portion of the security chain assembly whereby the dead bolt is engaged with a strike plate in the door jamb and the security chain assembly is latched to a chain latch assembly which forms a part of the strike plate. Operation of the externally accessible drive linkage to withdraw the dead bolt back into the lock is achieved without disengagement of the security chain assembly from the jamb mounted latch. A separate latch release is provided for disengaging the security chain. The lock body is provided with door penetrating detents which are actuated by the insertion of the dead bolt within the lock body whereby the detents are raised from within the lock body so as to lockingly engage with the door. No exterior screw fastenings are available to be tampered with, the lock body is enclosed within the door by the combination of exterior and interior plates and a latch plate. The door itself forms the remaining sides of the enclosure.