.~ Electrodes are pure figures of revolution about plug axis
DEFINITION
Classification: 313/138
(under subclass 118) Subject matter having plural ignition electrodes each of which is a pure figure of revolution about the longitudinal axis of the plug.
(1) Note. Where an electrode is only in part a figure of revolution, such as being a disk and in part not a figure of revolution, such as having a supporting spur, a perforated supporting means or a perforation, classification is not in this subclass.
SEE OR SEARCH THIS CLASS, SUBCLASS:
133, for this subject matter where one of the electrodes is ball shaped.
139, and 140, for similar subject matter in which one of the electrodes is not a pure figure of revolution. See subclass 139 where one of the electrodes is a disk or ring and the other electrode is not a pure figure of revolution, or where one electrode is only a section of a disk or ring and subclass 140 where one of the electrodes has a multi-pointed or serrated edge.
