US PATENT SUBCLASS 313 / 118
SPARK PLUGS

Current as of: June, 1999
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313 /   HD   ELECTRIC LAMP AND DISCHARGE DEVICES

118SPARK PLUGS {22}
119  DF  .~> Sealing-off valve for electrode chamber
120  DF  .~> With fluid feed or air vent
121  DF  .~> Reversible (e.g., part)
122  DF  .~> Removable electrode on shell
123  DF  .~> Plural series gaps {1}
125  DF  .~> Movable electrode (e.g., for cleaning, adjustable) {1}
127  DF  .~> Cleaner (e.g., movable scraper)
128  DF  .~> Plural insulated electrodes with individual lead-in
129  DF  .~> With transparent part
130  DF  .~> Non-conducting material in or adjacent gap (e.g., restricts spark) {1}
132  DF  .~> Capillary groove or space
133  DF  .~> Ball electrode
134  DF  .~> With radio shielding
135  DF  .~> With particular connector structure
136  DF  .~> Plural part center electrode lead-in
137  DF  .~> Plural part insulating means
138  DF  .~> Electrodes are pure figures of revolution about plug axis
139  DF  .~> Ring or disk electrode (e.g., sector)
140  DF  .~> Plural parallel gaps (e.g., main and standby, serrated electrode)
141  DF  .~> Particular electrode structure or spacing {1}
143  DF  .~> Shaped electrode chamber, insulator end, shell skirt, baffle or gas directing means
144  DF  .~> With specific joint structure {1}

DEFINITION

Classification: 313/118

(under the class definition) Unitary devices known as spark plugs.

(1) Note. See the glossary for the class 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. The shell is the part having means usually threaded for attachment to the cylinder. The shell may be made of more than one piece. Some plugs do not have a shell, the insulating core being attached directly to the cylinder, as by having screw threads thereon. The core is the insulating means fastened to the shell and holding the center electrode with respect to the shell. It may consist of several parts which may or may not be cemented to each other. The center electrode is the electrode or wire extending from the exterior to the interior of the spark plug and which is insulated from the shell by the core. There may be several center electrodes insulated from each other. The spark electrodes are the electrodes between which the jump spark is formed. The ignition spark gap is the gap on the interior of the spark plug designed to ignite the combustible fuel. A spark gap is constituted by two or more spark electrodes. The interior of the spark plug is the portion which will be exposed to the combustible gas. The exterior is the part usually exposed to atmosphere and which has the connector for the ignition wire mounted thereon. Electrode chamber is the space defined by the interior part of the core and the shell and exposed to the combustible gas in the engine. It may be substantially flat in some cases.

(3) Note. Spark plugs are collected here on the basis of use, art and structure. Spark plugs having the usual structure of a shell, an insulating core with one or more electrodes therein are found here. Due to the rules of classification, certain types of spark plugs and combinations of spark plugs with accessories are classified in the lower numbered subclasses of this class. Also, since the presence or absence of claimed sparking electrodes determines the classification in this class, a number of other classes provide for bushings, connectors, shields, joints and other subcombination features. Such other subclasses and classes are referred to in the notes below, and in cases where only a few patents are classified in other subclasses or classes and which are not noted in the notes, cross-reference patents have been placed in this and the indented subclasses.

(4) Note. Spark Intensifiers for Spark Plugs: Intensifier spark gaps designed for use with spark plugs are not classified in this or the indented subclasses unless the intensifier gap is a unitary part of the complete spark plug when see subclasses 123+. Where only the spark plug bushing (i.e., shell, core, center wire) is claimed, no ignition spark electrodes being claimed, the intensifier gap being located in or on the bushing, the patent is likewise excluded and classified as an intensifier gap. Some of the subclasses to be searched for these intensifier gaps are: 1+, where there are a plurality of intensifier gaps in a unitary device; 51, where the intensifier is claimed in combination with a detachable electric connector; 110+, where the intensifier includes an optical element as a lens, mirror, etc.; 146+, where the intensifier is provided with a movable or adjustable electrode or shield (e.g., a screw threaded

electrode so that the size of the gap may be adjusted); 238+, especially 243, 267, 268 where the supporting or spacing structure for mounting the intensifier electrodes are claimed; see subclass 267 where the electrodes are rods or rod-like members, subclass 268 where the electrodes are held apart by an insulating member between the electrodes, and subclass 243 for the other type; 324, for the intensifiers with a casing including those having a transparent window; and 567, especially 620+, 622, 634+ where the intensifier is mounted in a sealed envelope containing gas or vapor. SEE OR SEARCH THIS CLASS, SUBCLASS:

1+, for unitary devices providing two or more separate spark plug gaps or providing a spark plug gap and another discharge device, but excluding spark plugs with intensifier gaps for which see subclasses 123+ and spark plugs with a plurality of series spark gaps for which see subclass 123.

10, for spark plugs combined with a temperature indicator.

11.5, for spark plugs with temperature modifying means.

51, for spark plugs claimed in combination with a detachable electric connector (e.g., the connector on the lead-in wire).

54, for spark plugs which include a radioactive material.

110+, for spark plug devices which include means, see subclass 110 where the plug includes a lens, subclass 113 where the plug is combined with a mirror, subclass 116 where the plug includes a prism or light diffusing means.

513+, where the plug includes indicia or a scale (e.g., to show width between the ignition electrodes).

SEE OR SEARCH CLASS

15, Brushing, Scrubbing, and General Cleaning,

104.011, for spark plug cleaners.

73, Measuring and Testing, 118.1+, for spark plug testing devices. Also see Class 324, subclasses 378+ for spark plug testers.

123, Internal-Combustion Engines,

143+, especially subclasses 169 and 594+ for this subject matter in combination with an internal combustion engine or engine accessory. Subclass 169 relates, for example, to the combination of a spark plug and a cylinder head; the combination of a plug and cylinder space in which the interior of the skirt has a special claimed relationship to the cylinder volume the combination of a spark plug with an

adaptor of the screw coupling type (which, for example, permits a small plug to be inserted in a large hole or which acts to extend the shell skirt to provide a chamber for the spark), etc.. Also search Class 123 for plural separate spark plugs such as, for example, a plurality of adjustable spark plugs having means to adjust them.

138, Pipes and Tubular Conduits,

37+, for fittings or adapters to be interposed between the spark plug and the cylinder which include a flow regulator or baffle.

174, Electricity: Conductors and Insulators, appropriate subclasses for spark plug type electrical bushings (i.e., a spark plug with no sparking electrodes claimed), and electrical shields for spark plugs. See

15.1+, for such bushings combined with means for feeding, circulating or distributing a fluid, such as a cooling liquid or air, subclass 31 for such bushings with a fluid (air) vent, valve or other fluid feeding means combined therewith (e.g., a priming means), subclass 35 for such bushings with an electrical shield about it and for the spark plug shields, per se, and subclasses 152+ for such bushings, per se, including such bushings as are provided with thermal modifying means (e.g., heat radiating fins or heat conductive members) and electrical connectors. Note that Class 174 provides for subcombinations of spark plug type bushings which are less than a complete bushing and more than is provided for in other subcombination classes (e.g., the combination of the insulator and center electrode which involves more structure than a mere joint would be in Class 174 rather than one of the classes providing for joints.

285, Pipe Joints or Couplings, appropriate subclasses for fittings or adapters having joint means to attach one end of the fitting to the engine and joint means at the other end to receive a spark plug.

315, Electric Lamp and Discharge Devices: Systems,

32+, for space discharge devices, such as spark plugs, having integral therewith a circuit element such as a resistor, condenser or switch. Note particularly indented subclass 46 for spark plugs having a resistor in shunt to the sparking electrodes which is adapted to flash-over when traversed by a high current impulse, said flash-over serving to ignite the combustion charge; indented subclasses 51+ for spark plugs having a plurality of circuit elements, such as a resistor and a condenser; subclass 56 for spark plugs having an integral switch; subclass 57 for spark plugs having an integral transformer, and subclass 58 for spark plugs having a suppressor resistor. Note that spark plugs having only an integral intensifier (i.e., series connected gap) are classified in subclasses 123+ of Class 313. The presence of a separable connector or merely conductive lead (e.g.,

ignition cable) will not prevent classification in Class 315, subclasses 32+ if the device is otherwise classifiable there. Class 315 also provides for systems for supplying electrical energy to spark gaps. Note especially subclasses 209+ for such systems having a periodic switch (e.g., a timer switch) in the circuit and subclasses 211+ where there are a plurality of spark plugs and the system includes a distributor type switch. 361, Electricity: Electrical Systems and Devices,

247+, for miscellaneous ignitors and ignitor systems.

403, Joints and Connections, appropriate subclasses for a joint between metal and glass or ceramic members.

439, Electrical Connectors, appropriate subclasses for an electrical connector or certain connector related accessories. Note that Class 439 includes the combination of an electrical connector with a named spark plug. Search especially

125+, for an electrical connector having a spark or glow plug cover. Also, search subclasses 191+ for the combination of an electrical connector with a fluent material transmission line. Search subclasses 271+ for an electrical connector with a packing or gasket to seal the joint with a mating connector; subclasses 312+ for a coupling part with coupling part movement-actuating means or retaining means in addition to a contact thereof with relatively pivotable concentric movement-actuating or retaining ring. Search Class 439, subclasses 607+ for a connector with a radiation shielding means; and subclasses 625+ for a connector with insulation other than a conductor sheath.

445, Electric Lamp or Space Discharge Component or Device Manufacturing,

7, for methods of manufacturing spark plugs.

501, Compositions: Ceramic, appropriate subclasses for ceramic compositions used for spark plug insulators. Note especially

127+, and 134+ for clay containing compositions; and subclasses 141+ for titanate and similar material containing compositions.