ALEXANDRIA, Va., June 6 -- United States Patent no. 12,281,509, issued on April 22, was assigned to JKO Improvements LLC (Oconomowoc, Wis.).
"Automatic emergency door closure" was invented by James L. Opgenorth (Oconomowoc, Wis.).
According to the abstract* released by the U.S. Patent & Trademark Office: "An automatic emergency door closure is provided that can be used with an existing door by inserting a hinge pin assembly into knuckles of hinge plates associated with the existing door. The hinge pin assembly is movable between a first position where the door is held in a regular use position in which it can be opened and closed and a second position where the door is released to a closed position. This movement from the first position t...