ALEXANDRIA, Va., March 17 -- United States Patent no. 12,577,922, issued on March 17, was assigned to TPR Co. Ltd. (Tokyo) and TPR Industry Co. Ltd. (Yamagata, Japan).
"Cylinder" was invented by Takashi Oizumi (Yamagata, Japan), Seiji Tamaki (Tokyo) and Kiyoyuki Kawai (Tokyo).
According to the abstract* released by the U.S. Patent & Trademark Office: "A cylinder includes grooving in the inner peripheral surface of the cylinder. In the cylinder, the grooving includes a honed groove and recessed grooves of which the groove widths and groove depths are more than those of the honed groove, the honed groove and the recessed grooves extend in the circumferential direction of the cylinder and include an inclination angle with respect to a direct...