Intumescent fire door lock mechanism

摘要

A lock mechanism including a latch assembly for being attached to a movable door member and for movement between an extended position in which the movable door member is locked in a closed position and a retracted position in which the movable door member is allowed to move between opened and closed positions. A holding assembly is included for normally holding the latch assembly in the retracted position. Intumescent material is included for forcing the latch assembly to the extended position if subjected to heat above a certain temperature.