US1503643A - Spark plug - Google Patents

Description

Aug- 5! 1,so3,643 I A. DE CLAIRMONT SPARK PLUG Filed March 5. 1921 Parental Aug. s, 1924.

UNITED s'rAT'Es.

Anotro DE cLAmMoN'r, or rotmo, emo.

SPARK PLUG.

Application flled March 5, '1921.

To all whom it may concern: i

Be it known that I, ADoLro Dr. CLAIRMoN'r, citizen of the' United States, residing at Toledo, in the county of Lucas -and State of Ohio, have invented certain new and useful Improvements in Spark Plugs, of which the following is a specification.

This invention relates toan improved spark plug for internal combustion engines andv has as one of its principal objects to vprovide a device of this character wherein a condenser will be interposed between the main and ground electrodes of the plug to form primary and secondary spark gaps.

The invention has as afurther object to provide a plug -wherein the condenser will be formed by a sphericalelectrode so mounted that a primary spark gap will be provided within the shell of the plug at the upper side of said electrodefwhile secondary spark gaps Will be provided exteriorly of the shell at the lower side of the electrode.

A further object of the invention is to provide a plug whereinthe condenser will be suspended from the insulator ofthe plug and Wherein the supporting member for said condenser will be so formed and mounted'as to parallel the main electrode employed so that current flowing through the main -electrode' Will set up induced currents in said member for surcharging the condenser;

And the invention has as a still further object to provide a plug wherein the condenser as Well as the electrodes of the plug ma be readilyL cleaned.

ther and incidental objects will appear hereinafter.

In the drawing:

Figure 1 is a vertical sectional view takenl medially through my improved plug,1

Fig. 2 isI a detail section Vparticularly showing the mounting-of the condenser of the plug,

Figure 3 is a fragmentary vertical sec-' Vtional view illustrating a slight modification of the invention, and

Figure 4 is ai fragmentary vertical sectional view showing a further modified structure.

In carrying the invention into efi'ect, I

employ a shelllO, the lower end portion of.

which is externally threaded forl engagement 'in the usual spark plug orifice of an engine cylinder. Formed within the shell is an annular beveled shoulder upon which is arranged a suitable gasket 11 and Serial No. 449,965.

seating against said gasket is an insulator 12 of porcelain or other approved material. Surrounding the' insulator is a second gasket 13 of approved character and, as will now be observed, the shell is formed at its upper end with a reduced flange or neck 14. which is turned inwardly to coact with said gasket for tightly connecting the insulator with the Shell. Surrounding the upper end portion of the insulator above said flange is a protecting sleeve 16 beneath which is arranged a suitable sealing gasket 17 resting upon the flange and overlying said sleeve at its upper end is a similar gasket 18. The sleeve 16 may be formed of any approved material and is designed to protect the projecting upper end portion of the insulator against accidental injury. Extending axially through the insulator is a main electrode 19 provided near its upper end With a cylindrical boss or enlargement 20 having threaded engagement with the insulator and rising from said enlargement is a stud 21 of'a diameter somewhat greater than the diameter of the lower end portion of the electrode. Threaded upon said stud to coact With the porcelain is a lock nut 22 and threaded upon the stud to overlie said nut is a cap 23 cupped to accommodate the nut and seating against the gasket 18- for holding the sleeve 16 in position. Above the cap 23, the stud carries a binding nut 24.

The lower end portion of the insulator, below the body thereof, is tapered longitudinally While the main electrode 19 projects below the insulator and suspended from the insulator to coact With said electrode is a spherical condenser 25. -This condenser is sustained by a substantially U-shaped supporting member having parallel sides 26 joined by a straight connecting portion 27 and, as will be observed upon reference to Figure' 2, the condenser is provided with an eccentric opening therethrough to receive the connecting portion of said member While at the ends of said opening are appropriate notches accommodating the sides of the member. The condenser will thus be held against movement longitudnally of the connecting portion of the member and will also be looked against rotation. The sides of the member are arranged to straddle the main electrode 19 and are embedded in the insulator extending substantially parallel to sulator. The supporting member will thus be securely joined to the insulator without weakening said insulator and, as will now be observed, the member is arranged to sup-' denser. However, the condenser is disposed to project below the lower end of the shell, the equatorial lane of the condenser being disposed slight above the plane of the lower end edge o the shell and set into the shell at its lower end to cooperate with said condenser are diametrically arranged ground electrodes 28 providing secondary spark ga s between the lower side of the condenser an said electrodes exteriorly of the shell.

In operation, current flowing through the -main electrode will first jump to the condenser to provide a spark at the primary gap between said electrode and the condenser. From the condenser, the'current'will then jump to either or both of the ground electrodes to form Sparks at the secondary gaps of the plug, the interposition of the condenserbetween the main and ground electrodes Operating, as will be well understood, to greatly intensify the Sparks given off at the secondary gaps. Further, as will also be readil yappreciated, flow of current through t e main 4electrode will set up induced currents in the sides 26 of the supporting member for the condenser and these induced currents will tend to surcharge the condenser for further increasing the intensity of the Sparks given ofl' at the secondary aps. These gaps are located below the ower end of the shell so .that when the plug is connected with an engine cylinder, said aps may be entirely exposed within the com ustion chamber of the cylinder. However, fuel gases within said chamber will, of course, rise within the'shell so that the spark produced at the primary gap will also serve its function in igniting said gases. Preferably, the lower end of the insulator termin'ates substantially midway between the beveled internal shoulder of the shell and the lower end of the shell so that a considerable space between the lower end of the insulator and the condenser -is thus defined. A brush or cloth may 'accordingly be easily forced into the lower end of the shell for cleanin the lower end portion' of the main electro e as well as also cleaning the condenser. Further, by this 'arrangemang a pocket of considerable size is rovided within the lower end portion of t e shell forreceiving fuel gases to circulate around the primary spark gapnof the plug.A I

Figure 3 of the draw'ing, 'I have illustrated a slight modification of theinvention wherein the insulator, *indicated at' 29, is removably fitted'within the shell, the shell beying indicated at 30. The parts 29 and 30 correspond, of course, to similar parts of the referred construction and surrounding the insulator is a gasket 31 corresponding to the gasket 13. Threaded into the shell to'coact with'said gasket 'is a nut 32 binding the insulator within the shell and, as will be perceived, this nut may be removed for freeing4 the insulator. Otherwise, this modification is identical With the preferred form of the invention.

In Figure-4, I have illustrated a still further modification. In this'fi ure, the shell is indicated: at 33. Embedde in the lower end portion of the insulator, as in the preferred construction, are spaced rods 34 extending in parallel relation to the main' elsetrode 35 and jointly providing the sides of a supporting member for ai condenser 36. This condenser is in the natureof a disc and preferably, the rods are threadedinto said disc for securing the disc thereon. The coni denser 36 corresponds, of course, to the condenser 25 of'the preferred construction butv is, however, mounted in. spaced relation to the lower end of'the Shell so that the entire surface of the condenser disc is exposed below the Shell. In conformity with this arrangement, the main electrode35 is elongated to project below the shell so as to co-y operate with the condenser. Otherwise this modification is identical with the preferred construction. i

v Havingthus described the invention, what is elaimed as new is: i

1. A spark plug including a shell, an insulator carried thereby, a main electrode extending through the insulator, a spherical condenser suspended from the insulator below the lower end of said electrodein alinement therewith to intersect the plane ofthe lower end of the shell, the equatorial-plane of the condenser being dis osed above said first mentioned lane, an a ground electrode upon the sllfell, to cooperatewith said condenser... v

2. In'a spark plug, the combination of a shell, an insulator carried thereby, a main electrode extending through the insulator, a

'spherical condenser spaced below the lower end of said electrode to .form a spark gap between the electrode and the condenser, and a substantially U-shaped supporting member havin sides embedded at their free end portions in the insulator to straddle the main electrode and joinedb acOnnecting portion extending through said condenser supporting the condenser, thecondenser having notches therein accommodating the sides of said supporting memberl whereby the condenser 1s held against rotation as well as movement along said Lconnecting portion to prevent the length of the gap being varied.

3. In a spark plug, .the combination of a shell, an insulator carried thereby terminatlUlI d of the Shell to deshell below the inextending through g Within the shell operate therewith, a. supporting member suspending the cond and provided with tions paralleling the exposed enser from the insulator sides having exposed por- 'lower end portion of the electrode at opposite sides thereof Within said pocket, the space between the exposed portions of said sides and the exposed portion of said eleetrode being unobstructed, and a ground electrode upon the shell arranged to c'ooperate with said condenser.

In testimony Whereof I aflix my signature.

ADOLFO de CLAIRMONT, IW. D. [L. s.]

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