ALEXANDRIA, Va., Sept. 30 -- United States Patent no. 12,428,850, issued on Sept. 30, was assigned to MORRYDE INTERNATIONAL INC. (Elkhart, Ind.).
"Folding staircase" was invented by Gary E. Tompkins (Mishawaka, Ind.) and Anthony J. Granzotto (Constantine, Mich.).
According to the abstract* released by the U.S. Patent & Trademark Office: "A folding staircase for use in a door opening having a threshold. The folding staircase has a pair of stringers that have an upper end and a lower end that is adapted for contacting a ground surface. The stringers are spanned by at least one tread. A hinge is connected to a floor near the door opening and a threshold plate pivotally connected thereto is movable between a use position and a stowed position...