The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Dec. 29, 2020
Filed:
May. 30, 2017
Ngk Spark Plug Co., Ltd., Nagoya, JP;
Haruki Yoshida, Tajimi, JP;
Kuniharu Tanaka, Komaki, JP;
Yutaka Yokoyama, Kasugai, JP;
Shun Kondo, Obu, JP;
Hirokazu Kurono, Nagoya, JP;
Toshimasa Saji, Kounan, JP;
NGK SPARK PLUG CO., LTD., Nagoya, JP;
Abstract
A spark plug having an insulator with a leg portion whose outer circumferential surface has an arithmetic mean roughness Ra of 0.5 μm or less. The leg portion has a first section, a second section, and a third section. The first section has an outer diameter that decreases toward the forward end of the first section. The second section is located forward of and adjacent to the first section and its outer diameter decreases toward the forward end of the second section. The outer circumferential surface of the second section is located inward of a first straight line passing through the base and forward ends of the outer circumferential surface of the first section. The third section is located forward of and adjacent to the second section. The outer diameter of the third section is equal to or less than a forward end outer diameter Ds of the second section over the entire third section.