US1280113A - Automobile spark-plug. - Google Patents

Description

L. E. JOHNSTON. AUTOMOBILE SPARK PLUG.

APPLICATION FILED MAY l. I9I7.

Patented Sept. 24,1918?.

llelle xllnem LEWIS :EDWARD JOHNSTON, 0F SULLVAN, IVIISSOUR.

AUTOMOBILE SPARK-PLUG.

rescata.

Specication of Letters Patent.

Patented Sept. 24k, Multa.

Application filed May 1, 1917. Serial No. 165,802.

To all whom t may concern:

Be it known that I, Lewis EDWARD JOHN- s'roN, a citizen of the United States, and a resident of the city of Sullivan, county of Franklin, and State of Missouri, have in-` vented new and useful Improvements 1n ation of the device shall be materially in-y creased. i

One of the great difficulties encounter in the use of spark plugson interna-l combustion engines is the short-circuiting of the current passing through the plug, this action being due to the fact that the electrodes become coated with a deposit of carbon, soot, oil or other short-circuiting material and in time, this accumulation is effective in preventing the spark plug from performing its intended functions.

l propose to overcome the objection just noted by locating on the central electrode of the plug, a disk, theedge or periphery of which' lies immediately adjacent to the inner annular endof the spark plug body or shell,l

the same serving as the outer electrode, such construction providing a pair of annular edges between which the current may pass at any point to produce a spark. In other words, my iljfnproved construction provides for `an annu ar spark gap of considerable circumference, and if the greater portions of the two edges of the electrodes are coated with carbon or the like, there will still be suiicient space'on the edges for the production of the spark, thus enabling the plug to perform its normal functions.

One of the objects of my invention is to adjustably mount the disk upon the central electrode, thereby permitting the spark gap or space between the electrodes to be regulated according to the requirements of the particular coil-with which the spark plug is employed.

A further objectief my invention is to construct the inner end of the spark plug so as to prevent the accumulation of short-cir cuiting material on the spark points or edges, thereby tending to maintain the same .in a clean and serviceable condition.

With the foregoing andother objects in view, my invention consists in certain novel features of construction and arrangement of parts, hereinafter more fully described and claimed, and illustrated in the accompanying drawings, in which- Figure 1 is a side elevational view of a spark plug constructed in accordance with my invention;

Fig. 2 is a vertical section taken lengthwise through the center of the spark plug with a portion of the insulated core thereof in elevation.

Referring by numerals to the accompanying drawings, which illustrate a practical embodiment of my invention, 10. designates the outer` shell or body of the plug, the same being formed of metal and provided intermediate its ends with an internally arranged shoulderll. The upper end of this shell or body is internally threaded as designated by 12, and the lower end is externally threaded as designated by 13 in order that said body may be screw-seated in the wall of an internal combustion engine.

A core 14 of insulation, preferably porcelain is provided intermediate its ends with an annular rib 15 and when this core is properly positioned in theshell or body 10, the shoulder on the underside of said rib bears directly upon a gasket or packing ring 16, which latter rests directly upon the shoulder 11.

A gland or packing ring 17 is screwed into the threaded upper end of the body 10, the lower end of said gland or rin bearing directly upon the shoulder above t e rib 15.

Extending axially through the core la is the central electrode 18, the same being in the form of a metal rod, both ends of which are threaded and formed on or xed to the lower portion of said rod and'immediately.

above the threaded lower end thereof dis a disk 19 which lits snugly within a recess 20 formed in the lower end of core lil.

A portion of the threaded lower end of this electrode extends belowthe lower end of the shell or body 10 and screw-seated upon said lower portion is a disk'l, the top surface of which is preferably flat and the under-surface being convex. Formed through this dial; is an aperture wl 'ch is adapted to receive a suitable tool arxxreby the disk till lill* irc ma be screwed up or down upon the centra electrode to regulatethe distance be tween the edge of said disk and the annular lower edge of body 10. The extreme lower end of electrode 18 is pointed as `deshgnated by-23. The threaded upper portion of electrode 18 is provided with nuts 24 and 25 between which the terminal of a conductor may be clamped and interposed between the nut 24 and the top of core 14 is a packing disk 26.

It will be understood that the electriccurrent delivered to the spark plug by a line connection clamped between the nuts 24 and 25 passes downward through electrode 18, from thence through disk 21 andin jumping to the lower edge Vof the cylindrical body 10, produces a spark, thereby igniting the cornpressed charge within the engine cylinder.

The width of the spark gap can readily be regulated by adjusting the position of disk 2l on the threaded lower portion of electrode 18, this operation being accomplished by means of a suitable. tool inserted in the aperture 22 and rotating said disk 21.

It will 4be noted that the disk 21 forming the central electrode has a diameter `that is equal to or slightly larger than the internal diameter of the lower portion of shell 10 and for this reason any carbon or oil which may be thrown onto the convex undersurface of said disk 21 will be directed outwardly and upwardly and thus be prevented from entering and accumulating within the chamber between said disk 21 and the lower end of the. porcelain body 14.

It has been demonstrated in practice that there is no tendency of carbon or the like to accumulate on the convex underside of disk 21 and the pointed end 23 of electrode 18, and it is believed that this self-cleaning action is due to the sweeping or wiping action of the compressed gases during the tiring ac tion or while under combustion. Further, it has been noted thatthe spark produced by my improved plug will travel from one `point to another around the annular spark gap, and by virtue of the fact that said spark gap is continuous or in the form of a circle' the plug will continue to perform its tunetions even though considerable portions of the edge of disk 2l and the lower edge of shell 10 bc covered with a coating or deposit of carbon or the like.

For this reason my improved spark plug can be used continuously for a much greater period of time than a spark' plug having a spark gap formed between the attenuated ends of a pair of electrodes.

lit will be readily understood that minor changes in the size, form and construction of the various parts of my improved spark Laetrile" plug can be made and substituted for those herein shown and described, without departing from the spirit of my invention, the scope of which is set forth in the appended claims. A

I claim:

1. The herein described spark plug comprising a substantially tubular body, a. core of `insulation withinsaid body, the .lower end of which core terminates a shortdistance above the lower end ofthe tubular body, a rod passing through the core, the lower portion of which rod is threaded and projects below the lower end of the tubular body, a nut mounted on the threaded lower end of the rod and occupyingk the recess formed in the lower end of the core, and an electrode in the. form of a disk positioned on the threaded lower end of the rod below the cylindrical body, said disk having a diameter slightly greater than the internal diameter of the tubular body, andl provided with a fiat top surface and a smooth'convex lower face, and the end of the rod which projects below said disk being pointed.

2. The herein -described spark plug comprising a substantially tubular body, a core of insulation within said body, the lower" end of which core terminates a short distance above the lower end of the tubular body, a rod lpassing through the core, the lower portion of which rod is threaded and projects below the lower end of the tubular body, a nut mounted on the threaded lower end of the rod and occupying the recess formed in the lower end of the core, and an electrode in the form of a disk positioned on the threaded lower end of the rod below the cylindrical body, said disk having a di-v ameter slightly greater than the internal diameter ot' the tubular body, and said disk having a lflat top surface and a smooth convex lower face and provided with an eccentrically arranged aperture adapted to receive a tool whereby said disk can be screwed ondto or from the threaded lower end of said ro 3. A spark plug having a substantially tubular body, a core of insulation lwithin said tubular body, a rod passing through said core, the lower portion of said rod being threaded and projecting a substantial distance below'the lower end ofthe tubular body, the extreme lower end of said rod being pointed, and an electrode of disk form screw-seated on the threaded lower portion of the rod,. the edge of which disk is disposed adjacent to the lower end of the tubular body, and said disk having a smooth convex lowerl face.

LEWIS EDWARD JHNSTUN.

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