ALEXANDRIA, Va., June 16 -- United States Patent no. 12,308,620, issued on May 20, was assigned to NITERRA Co. LTD. (Nagoya, Japan).
"Spark plug" was invented by Takaaki Kikai (Nagoya, Japan) and Satoshi Noguchi (Nagoya, Japan).
According to the abstract* released by the U.S. Patent & Trademark Office: "To provide a spark plug that can ensure the strength of a melt portion, the spark plug includes: a center electrode; a metal shell in which the center electrode is insulated and held, the metal shell including a cylindrical portion having an outer circumference provided with an external thread, the metal shell further including a hole penetrating the cylindrical portion in a radial direction; and a ground electrode protruding from the meta...