US Patent 7213426 Storm door mortise lock that prevents lockout

A method and apparatus for providing a storm door mortise lock that prevents lockout with a lock body having opposed side plates and a cam in between the side plates, the cam being in operative interaction with a dead bolt assembly. The mortise lock body also may include one or more stops within the deadbolt assembly to limit the rotation of the cam and prevent a lockout situation. A thumb turn button and key cylinder are secured to opposite escutcheon plates. A spindle traverses from the key cylinder through the cam through hole and terminates in the mounting slot of the thumb turn button. Rotation of either the thumb turn button or the key cylinder turns the spindle and actuates the cam that actuates the dead bolt assembly.