Segner & Bretschneider
Spark plug with a sphere-like metal center electrode and manufacturing process thereof
 A spark plug with a sphere-like center discharge electrode is obtained by pressing a sphere-like metal essentially consisting of noble metal Au, Ag and/or alloys thereof with Pd or the like set on a small end bore formed at a discharge end bottom of a ceramic insulator. Sealing of a sealing material and/or resistor material together with setting (sealing) of a terminal body may be done simultaneously with the pressing of the sphere-like metal on the small end bore by means of hot-pressing applied on the terminal rod head. 
NGK Spark Plug Co.
H H
H01T H01T
inventional inventional
Yasuhiko Kanemitsu Shunichi
Suzuki Nishio Takagi