Patent ID: 7557495
Filing Date: 2009-07-07
Classification: H01T

Abstract:
1. A spark plug for use with an internal combustion engine, comprising: a shell having an axial bore; an insulator having a central bore and being at least partially located within said shell axial bore; a center wire assembly extending through said insulator central bore, said center wire assembly including a center electrode; a ground electrode having an attachment end, a free end and a side surface, wherein said ground electrode extends from said attachment end at said shell to said free end such that a portion of said side surface adjacent said free end is positioned opposite a firing end of said center electrode; a precious metal pad having a sparking surface, a diameter (E) and a thickness (K), wherein said precious metal pad is welded to said portion of said ground electrode side surface via a weld bead having the following characteristics: i) said weld bead generally circumferentially surrounds said precious metal pad, ii) said weld bead inner diameter (I) is less than said precious metal pad diameter (E), iii) said weld bead outer diameter (J) is greater than said precious metal pad diameter (E), iv) said weld bead includes a plurality of overlapping weld spots, and v) each of said weld spots has a weld bead depth (G) that is generally greater than said precious metal pad thickness (K).