Emergency exit door latching and locking apparatus

摘要

Emergency exit door latching and locking apparatus includes a closure operated latch bolt which is mounted in a U-shaped pivoted carrier link by a pair of links for projection from the carrier link to latch the door. The carrier link is connected to a toggle linkage which in a first position dogs the carrier link and bolt projected and when urged over-center allows the carrier link to pivot so as to carry the bolt to a retracted position while the bolt is still projected from the carrier link. A panic push bar is used to move the toggle over-center and to thereafter engage a projection on the door so as to urge the bolt to the retracted position due to pressure applied on the door. A detent is disposed to move between the bolt and pivot for the carrier link so as to keep the bolt projected when the detent engages a strike on the door jamb. When the door is moved from the open position to the closed position, the detent is disengaged from the pivot and the bolt retracts into the carrier link. The panic push bar is mounted by a pair of bell cranks connected with a tension rod so that tension applied anywhere on the push bar will operate the push bar to move the toggle linkage over-center. A hydraulic throttling means is connected to the toggle linkage to delay retraction of the bolt and an alarm is activated upon retraction of the bolt during the delay to signal that someone is trying to open the door.