(under subclass 118) Subject matter having means, integral with the spark plug, permitting the removal of a part of the spark plug from normal operating position with respect to the
portion of the shell which is attachable to the cylinder, without forming an open passageway from the cylinder to the atmosphere.
(1) Note. Included in this subclass are only unitary spark plugs. See Class 123, Internal-Combustion Engines, subclasses 143+, especially 169 for similar subject matter where the plug is combined with another separable device (as a fitting with a valve) which permits removing of the plug without stopping the engine.
(2) Note. These spark plugs are designed usually to permit inspection or repair of the ignition spark gap electrodes or of the interior end of the insulator without stopping the operation of the engine.
SEE OR SEARCH THIS CLASS, SUBCLASS:
236, for other discharge devices which have a stand-by or spare electrode.
237, for other discharge devices which have electrode replacement means or are demountable. SEE OR SEARCH CLASS
137, Fluid Handling, appropriate subclasses for automatically operated valves.
251, Valves and Valve Actuation, appropriate subclasses for manually operated valves.
