ALEXANDRIA, Va., Oct. 28 -- United States Patent no. 12,454,831, issued on Oct. 28.
"Folding stair with tread overhang" was invented by Matthew Yeatman Herzl (Marshall, Ark.).
According to the abstract* released by the U.S. Patent & Trademark Office: "An improved folding stair comprising a sequence of steps (101), each rotably mounted to a structure (102) via axes (103) located and oriented to facilitate rotation between deployed and stowed states, such that the steps exhibit tread overhang (109) in their deployed state. The step width (105) exceeds the step rise (107). In other embodiments the axes are to one side of the steps. In other embodiments the angle of rotation between deployed and stowed states exceeds the arccosine of step-abo...