US Patent 11428039 Emergency door closing device

An emergency door closing device that can be installed upon existing doors and hinges to automatically close doors in the response to smoke and fire. The improvements incorporated therein include a hinge cam pivot member that attaches to an existing hinge member of a door and produces a moment force about the existing hinge member allowing a reduced force necessary to pivot the door into a closed position. Further, a novel spring, cam, and lever system is incorporated to activate the moment force to close the door.