(under subclass 11) Unitary devices known as spark plugs.
(1) Note. See the glossary of this class definition, for a definition of spark plugs. In general, the spark plugs classified herein are the jump-spark type found in the gasoline engine of an automobile.
(2) Note. This subclass contains patents relating to spark plugs where the temperature modification of some part of the plug is material. If the plug is provided with gaskets or joints are of high or low heat conductivity, the patent would be included. A plug having gaskets or joints formed of particular materials would be classified in subclasses 144+ if it was not stated the materials were selected for their temperature modification properties.
(3) Note. Preheating of the gas charge (before the spark jumps) by heat left in the spark plug from a previous explosion stroke cycle is not basis for classification in this subclass unless such preheating is accomplished by means which are especially provided to alter the temperature of the spark plug.
SEE OR SEARCH THIS CLASS, SUBCLASS:
120, for spark plugs having means to feed a fluid, such as priming fluid or air, where there is no disclosure that the
temperature of the spark plug is affected by the fluid feed. 126, for spark plugs having means to move an electrode in response to a thermal change and having no means to influence the thermal characteristics of the spark plug.
SEE OR SEARCH CLASS
174, Electricity: Conductors and Insulators,
15.3, and 152 for spark plug type electrical bushings (a spark plug with no sparking electrodes claimed) having temperature modifying means. See subclass 15.3 where the bushing is combined with means for feeding, circulating or distributing a temperature modifying fluid.
439, Electrical Connectors,
190+, and 485+ for an electrical connector, including the spark plug type, with temperature modifying means.
