Emergency latch for a hatch structure

Claim 1

In a hatch structure comprising a frame and a door hung in said frame to close by gravity, operating means facilitating the manual movement of the door between open and closed positions relative to said frame and comprising a brace hinged to the frame, a track member mounted on said door, and slide means at the unhinged end of said brace confined for sliding movement in said track member with opening and closing of the door, the improvement which consists of latching means for coacting with said operating means to latch said brace in door-open position but releasable automatically upon occurrence of fire to release said brace and permit said door to close, said latching means comprising: a catch member mounted on the door and a cooperating keeper member secured to the unhinged end of said brace, said keeper member being engagable by said catch member in the open position of said door to prevent sliding of the unhinged end of the brace relative to the track member; a carrier member movably mounted in said latching means; said catch member being pivotally mounted on said carrier member for movement toward and away from latching position relative to said keeper, said carrier member being independently movable in said latching means between latching position wherein said catch can engage said keeper and disabled position wherein it cannot, means releasably retaining said carrier member in position to enable said catch to engage said keeper, and spring means biasing said catch towards keeper-engaging position; said retaining means for said carrier including severable linkage means holding said carrier in said latching position.