ALEXANDRIA, Va., June 16 -- United States Patent no. 12,305,679, issued on May 20, was assigned to Max Co. Ltd. (Tokyo).
"Screw nail" was invented by Eiichi Watanabe (Tokyo) and Ryuta Kurasawa (Tokyo).
According to the abstract* released by the U.S. Patent & Trademark Office: "A screw nail includes a nail shaft portion extending along one direction, and a head portion whose diameter is enlarged along other direction orthogonal to an extension direction. A sharp tip end portion is formed on one end side of the nail shaft portion, and the head portion is formed at an end portion on the other end side. The nail shaft portion is formed with a screw thread, and the head portion is formed with an engaging portion capable of engaging with a rota...