Patent ID: 8146962

Claim:
A latch structure of fire door lock comprising: a lock base having a bottom portion, a first lateral portion, a second lateral portion and an accommodating slot defined by the bottom portion, the first lateral portion and the second lateral portion; a linking set having at least one first linking member, the linking set is disposed at the accommodating slot of the lock base; a fixing rod pivotally connected with the first linking member of the linking set, the fixing rod comprises a first fixing end and a second fixing end fixed at the first lateral portion and the second lateral portion respectively; a latch unit having a latch bolt, at least one actuating member, a penetrating bolt and a combining pin, the penetrating bolt is pivotally connected with the latch bolt and the actuating member, the combining pin is pivotally connected with the actuating member and the first linking member and configured to move along a path, the latch bolt is swingably disposed at the accommodating slot of the lock base, and the latch bolt can be driven between a projected position and a retracted position in response to the movement of the actuating member; and when the latch bolt moves to the projected position, the penetrating bolt and the fixing rod may define a line which crosses the path, wherein the combining pin moves toward the bottom portion of the lock base along the path and stops moving until the combining pin crosses the line.