ALEXANDRIA, Va., March 12 -- United States Patent no. 12,249,809, issued on March 11, was assigned to Niterra Co. Ltd. (Nagoya, Japan).
"Spark plug insulator and spark plug" was invented by Hiroki Shimada (Nagoya, Japan), Haruki Yoshida (Nagoya, Japan), Kengo Fujimura (Nagoya, Japan) and Takuto Koba (Nagoya, Japan).
According to the abstract* released by the U.S. Patent & Trademark Office: "When a force to bend a spark plug insulator is applied to the spark plug insulator to fracture the spark plug insulator, for a range including a starting point of the fracture out of two ranges into which a fracture surface created by the fracture is divided by a plane which is a plane perpendicular to a direction of the force and includes the axial li...