FIRE DOOR LATCH ASSEMBLY INCORPORATING FIRE FUSE WHICH MELTS AT HIGH TEMPERATURE TO PREVENT RELEASE OF LATCH

摘要

A latch assembly for a fire door having a pushpad for emergency exit is described. The pushpad is connected to a rod to transfer motion of the pushpad to the latch assembly. The latch assembly includes a platform attached to the fire door, a linkage assembly attached between the rod and a latch bolt, and a deadlock arm assembly attached to the platform. The deadlock arm assembly is movable between a first position to block movement of the linkage assembly and a second position to allow movement of the linkage assembly. A fire fuse assembly is also attached to the linkage assembly to move the deadlock arm assembly out of its first position blocking movement of the linkage assembly at normal room temperature. The fire fuse assembly is configured to melt at temperatures substantially above normal room temperature to prevent engagement between the fire fuse assembly and the deadlock arm assembly, effectively preventing movement of the deadlock arm assembly out of its first position blocking movement of the linkage assembly in response to movement of the rod.