US1360946A - Spark-plug - Google Patents

Description

G. V. HARRIMAN.

SPARK PLUG. APPLICATION FILED DEC. 3. 191s.

151360,946. l Patented Nov. 30, 1920.

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SPARK-PLU@ Specification of Letters Patent.

Patenten nav, se, ieee.,

Application led December 3, 1918. Serial io. 265,105.

To all whom it may concern:

Be it known that l, GEORGE V. HARRIMAN, a citizen of the United States, residing in yNew York city, in the county of New York and State of New York, have invented certain new and Vuseful improvements in Spark-Plugs, of which the following is a specification.

My present invention relates to an iinprovement ire-plugs for use in internal combustion engines, and the principal object of my invention, in addition to. providing a spark plug of great eliiciency, is to obviate short-circuiting of the spark plug due to the coating, parbOniZing, or bridging of the ignition points thereof., l

l attain this object by the device illustrated in the accompanying drawing, which is a sideview of my improved spark plug, partly in vertical section, and in which similar numerals refer to similar parts, as related to my invention as set forth in this specification.

My improved spark plug comprises in its main elements or parts, a shell or bushing 1, and an insulator core generally denoted by 2, and preferably made of porcelain.

The shell or bushing is chainbered to receive the insulator core 2, and has a threaded lower exterior portion 3, for attachment to the cylinder of an internal combustion engine. and has an interiorly threaded upper portion Il, to receive a compressive threaded bushing hereinafter more fully described. The chamber of the shell or bushing l, below the interiorly threaded portion 4, is vertical and terminates at its base in an inwardly extending ledge or flange 5, the vertical side of the chamber and the ledge or flange 5, forming alright angle, when viewed in vertical cross-sec-` tion. The shell or bushing 1, has at its lower end a terminal wire 6, which is embedded or otherwise suitably fixed to the` the horizontal base or the shoulder are arranged to engage respectively the'vertical sides and the upper surface of the flange 5, of the chamber of the shell or bushing 1, and the downward extension 8, of the insulator core is arranged to it closely the oriioe or opening at the bottom of the shell or bushing 1, the purpose being to prevent entrance of gases or matter into the chamber of the shell or bushing, or contact thereof with the insulator core 2.

The projecting end, or firing pin end 9, of the insulator core 2, is in length exaggerated, that is. it is made longer than customarily used in spark plugs, to permit insertion thereof well into the ignition space of the engine cylinder, -with the ignition portion of the spark plug, and owing to the preventing of entrance ot` gases between the shell or bushing 1, and the insulator core 2, as above sta-ted, that when my spark plug is subjected to the high heats ofl ignition and the swirling Cyclonic action of heated gases, the porcelain portion of the plug is thoroughly scoured or' deleterious deposits, and that the surface of the truncated cone shaped tiring pin end 9, does not become coated, and there is no tendency to shortcircuit between the electrode or firing pin and up and through carbon deposits customarily formed thereon, to the base of the shell or bushing 1.

The insulator core 2, is provided with a longitudinal duct 10. for a central electrode or firing pin 11, which coacts with the terminal wire 6, to forni a'sparking gap in accordance with the well known practice. rlhe tiring pin, 11, has a shoulder 12, which engages a ledge 13, located within the lower extremity oi the insulator core 2.

rlhe upper end 'of the liring-pin 11, has a thread 14:, to receive a lock-nut 15, and the usual thumb-nut 16, whereby electrical contact may be made.

A compressive exteriorly threaded bushing 17, is provided to engage the interiorly threaded portion of the shell or bushing 1, and to receive the insulator core 2.

A packing or gasket 18, is provided for the space formed by the diminished portion of the insulator core 2, above the shoulder 7 and between the interiorly threaded portion or the shell or bushing 1, the packing oi' gasket being securely held in place by the compressive bushing 17, the inward curve of the shoulder 7, conducing the lil@ tightness and serving as a thrust shoulder for maintaining the insulator core 2, in .it-s proper operative position.

The packing or gasket, 18, may be of any suitable material, such as asbestos.

In practice I have found that owing to the close contact respectively of the vertical sides and the horizontal bottom of the shoulder 7, of the insulator core with the vertical sides and the upper surface of the ledge of the chamber of the shell, and the close contact of the downward extension 8, of the insulator core with the bottom opening or orifice of the shell, the lodgment of oil or carbon between these parts is prevented, and a starting point for a carbon bridge is eliminated. And furthermore, the packing 18, by compression of the bushing, 17, is forced inwardly and downwardly against the curved portion of the insulator core 2, thereby to maintain the insulator core in operable position.

In numerous trials of a plug made as herein set forth, I have found that the firing pin end of the plug of exaggerated length and of substantially truncated cone shape, has' continued to operate for long periods, without trouble due to short circuits formed by carbon, orv soot bridges, or the like.

I claim:

A spark plug comprising a shell having means for engagement with an internal combustion engine, and provided with a chambered interior open at top and bottom having a vertical side wall, and having an inwardly extending ledge at the base of the shell at right angles to said side wall, and having an arcing terminal at the bottom of said shell, an insulator core partly contained in said shell and having a vertically sided shoulder with a horizontal base, said shoulder curving inwardly at its upper end to the diameter of the insulator core, and having a downwardly extending portion adjacent to and below said shoulder, and having a downwardly projecting end of truncated cone shape, a firing-pin arranged within the insulator core having an arcing terminal extending from said truncated cone shaped end, and having a shoulder at the lower end engaging the lower end of the insulator core, a compressing bushing for engaging the upper interior of the shell and having a downward extension of exterior diameter substantially the same as the diameter of said shoulder, and having a longitudinal passage therethrough of diameter to engage closely the insulator core, there being space formed between the lower end of said bushing and the upper end of said shoulder, a packing for said space, a locknut for the upper end of the firing-pin, and means for electrical contact; said packing being compressed by said bushing to prevent passage of gas, and the inwardly curving portion of the shoulder of the insulator core forming with the vertical side wall of the chamber of the shell an outwardly curving bottom to the above mentioned space to force the packing inwardly and downwardly when compressed against the insulator core to maintain the insulator core in operable position in said shell.

GEORGE V. HARRIMAN. Witnesses:

W. L. MosELEY, MARTHA VoLz.

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