US Patent 7259506 Spark plug with perpendicular knife edge electrodes

A spark plug has an elongated body of substantially circular cross-section with a center axis. A wedge shaped center electrode extends from one end of the body and a wedge shaped ground electrode is arranged in close proximity to the center electrode. Each of the electrodes includes an elongated knife edge. The knife edges extend radially with respect to the center axis but lie in different parallel planes that are perpendicular to the axis. The two knife edges of the electrodes are spaced apart from each other and extend perpendicular to each other.