(under subclass 118) Subject matter having a transparent part.
(1) Note. The transparent part may, for example, make the spark or explosion inside the engine cylinder visible to an observer.
SEE OR SEARCH THIS CLASS, SUBCLASS:
110+, for spark plugs where the transparent part is an optical device such as, for example, a lens. See subclass 116 where the transparent part has light diffusing properties.
120, for spark plugs having fluid feed or air vent means, through which the spark gap may be observed.
124, for spark plugs having an intensifier gap and the portion of the plug having the intensifier gap is provided with an observation window or is made transparent.
324, for miscellaneous spark gaps which are provided with a casing having a transparent part.
