Automatic deadbolt mechanism for a mortise lock

An automatic deadbolt mechanism comprising:

• a deadbolt movable between a retracted deadbolt position and an extended deadbolt position, the deadbolt biased in the extended deadbolt position;
• an auxiliary latch movable between a retracted auxiliary-latch position and an extended auxiliary-latch position, the auxiliary latch biased in the extended auxiliary-latch position;
• a trigger biased in a first trigger position and movable between the first trigger position and a second trigger position, the trigger operatively coupled to the deadbolt and to the auxiliary latch, the trigger configured to be in the first trigger position when the auxiliary latch is in the extended auxiliary-latch position and in the second trigger position when the auxiliary latch is in the retracted auxiliary-latch position, to cause a first movement of the deadbolt from the retracted deadbolt position to the extended deadbolt position when the trigger moves from the first trigger position to the second trigger position, and to require movement of the auxiliary latch a predetermined distance from the retracted auxiliary-latch position toward the extended auxiliary-latch position before the trigger is able to cause a second movement of the deadbolt;
• a deadbolt holding lever biased in a first deadbolt holding-lever position and pivotable between the first deadbolt holding-lever position and a second deadbolt holding-lever position, the deadbolt holding lever configured to releasably retain the deadbolt in the retracted deadbolt position when the deadbolt holding lever is in the first deadbolt holding-lever position;
• and
• a release lever biased in a first release-lever position and pivotable between the first release-lever position and a second release-lever position, the release lever configured to cause the deadbolt holding lever to pivot from the first deadbolt-holding-lever position toward the second deadbolt-holding-lever position when the release lever pivots from the first release-lever position toward the second release-lever position,
• wherein the trigger is operatively coupled to the release lever and is configured to cause a first pivot of the release lever from the first release-lever position to the second release-lever position when the trigger pivots from the first trigger position to the second trigger position, and to require movement of the auxiliary latch a predetermined distance from the retracted auxiliary-latch position toward the extended auxiliary-latch position before the trigger is able to cause a second pivot of the release lever, and
• wherein the release lever has a trigger-lever engaging arm and the trigger comprises:
• an auxiliary-latch lever pivotable between the first trigger position and the second trigger position, the auxiliary-latch lever biased in the first trigger position;
• a stop extending from the auxiliary-latch lever;
• and
• a trigger lever pivotably connected to the auxiliary-latch lever, biased in a first trigger-lever position abutting the stop and pivotable between the first trigger-lever position and a second trigger-lever position, the trigger lever having a release-lever engaging end slideably engageable with the trigger-lever engaging arm.