US2017364A - Spark plug with supported gap - Google Patents

Description

Oct. 15, 1935. A. E. ANDERSON SPARK PLUG WITH SUPPORTED GAP Filed Aug. 3, 1934 IN V EN TOR.`

patented April 25, 1933.

Gil

Patented et. l5, 19.35

man

UNITED STATES PATENT OFFICE SPARK PLU'G wrm scrron'rnn on August Eugene AndersomMontclair. N. J. I Application August 3,1934. sei-n1 Nmssis whims. (ci. 12a-16e) This invention relatesto spark plugs for internal combustion engines, and more particularly is an improvement upon the device and construction described lin my Patent No. 1,905,957,

One object of' my invention is to provide a moderate depositof carbon `on the electrodes and I have made extensive tests to prove that this is not a detrimental factor to the good performance of a spark plug, as'sorne manufacturers and inventors assume, and therefore have taken precaution to keep the electrodes free from carbon, thereby weakening the electrodes to a point of preignition, from poorly constructed and devised lelectrodes which preignition is very damaging to an internal combustion engine, sometimes proving fatal.

In my drawing and specification a good construction of electrodes is described and shown for collecting a medium amount of carbon which is a good sign that .they are free from preignition, and that the carbon so collected has a value in cutting down the resistance in my supported spark gap, thereby giving a hotter vspark and longer life to There is no danger of the collected carbon on the electrodes making a short or close circuit ,in the spark gap, as the electrical action of the spark will burn away any excess of such deposits in the gap.

Tests have been made by putting my novel spark plug with supported gap in parallel with other makes of' spark plugs and this has proved my plug tovhave a full, fat spark at all times, while there was not a sign of any sparks from the other spark plugs so tested in parallel with mine.

Another object o! my invention is to cool the inner middle portion of the spark plug. This is accomplished by furnishing an open space between the insulator or with suitable vents in 'cooling air around the porcelain.

Water or otherv liquid may also be used for this purpose,

when pipe connection to the vents from a suit# able source is provided.

By collecting a medium amount of carbon on the electrodes, the carbon so collected will cut down the resistance in theelectrical current, thereby eliminating certain radio interferences in radio equipped cars. I have found that a medium amount of collected carbon with my novel arrangement of the spark gap, has proved to be of such good advantage that it is not necessary to equip a car with the usual Suppressors or shielding of the wires, that cars equipped with conventional spark plugs must have.

Still another object is to design the central or main electrode in such a way that when asseinV bling the same into the porcelain insulator, time `with a bent down spark point.

the electrodes and spark plug itself.'

porcelain and the housing the latter for circulating lated support and spark with less resistance.

v be thev usual hooked one secured in the metal housing or else made in the form of a gasket Both may be 15 used together. f v

I prefer to provide a gasket placed at the lower end, or at the hottest part of the insulator to prevent the porcelain from cracking and carrying the heat to theshortest cooling path. And I also find that the compression leak becomes less by placing a gasket inthis manner.

Another object is to construct a central electrode with a smaller diameter at the point where the smallest part of the porcelain is located, land. the heat is the greatest. A central electrode constructed in this mannerV as shown in the drawing will prevent the porcelain from cracking at this point. By placing a gasket at the lower end ci theinsulator makes it possible to construct the porcelain in a fashion so as to leave a space for alrcirculation `around the inner part of the porcelain insulator', thereby cooling the same.

lWith a gasket at the lower end of the porcelain insulator, the same may serve as ground electrode with a spark pointvmade integral theref with as above described and shown on the drawing, thereby eliminating the conventional grounded electrode secured in the lower part of the spark plug housing.

A very `important object of my park plug with supported gap is that the action of the electrical current traveling on top of the porcelain or insuacross the gap between the 4 points of the electrodes, places a deposit ofa nonconducting substance forming a path that when mixed with the compressed gas charge, has a tendency to materially helpto pro-duce a hotter This feature cannot be produced with any other conventional type of spark plug with an open non-supported gap.

My invention is illustrated in the accompany ing drawing in Which:-

ligure l shows'a longitudinal, axial section of my spark plug;

Fig. 2 a detail in larger scale of the central elec-1 trade;

. Fig. 3 a transverse section along 3-3 of Fig. '2;

Fig. e an end view of the lower portion. ci the @a of the arrangement of the spark plug with two spark points and spark gaps. and

the porcelain is seated on an annular ledge 20' formed at the threaded lower or inner end of the housing I with a. metal gasket `3|I inserted between them. It will thus be seen that the porcelain is held firmly between the two gaskets 9 and 30 when the nut is tightened down.

The porcelain I2 terminates with a sleeve or skirt 21 projecting below the ledge 2Q of the housing. Between the ledge 420 and the skirt 21 is formed an annular spaceor groove 2| for cooling the skirt.

.The central or main electrode, as best seen in Fig. 2 is formed by two metal rods I3 and Il which, when assembled, fit in the axial bore formed through the entire length of porcelain I2. The upper or outer end of the electrode portion I is threaded in the porcelain and terminates with a smaller thread shank 32 for attaching` the wire. The cylindrical inner end of the electrode portion I4 is bifurcatedor provided with a longitudinal slit I9 adapted to receive the flattened tongue I8 on the upper end of the other electrode portion I3. When assembling the electrode I3, I4 in the base of the porcelain, cement is rst poured in from ille threaded end of the bore and the main electrode portion I4 screwed down tight therein. The

portion I3 is thereupon pushed up in the bore un.

til the tongue I8 engages the slit I9 and the enlarged head I'l abuts against the end of the sleeve or skirt 21. The cement will then surround the electrode in the bore and particularly ll in the .spacearound the constricted part I6 thereof to hold it rmly in place.A Any excess cement around Ythe head` I'I ls thereupon scraped olf. 'I'hls head is smaller in diameter. than the end of the skirt 21, so as to form the supported insulated gap between ground and central electrode as in Fig. 4. The ground electrode 23 may in the usual manner be secured in the end of the housing I0 as indicated in Fig. 1, but my preferred construction is best shown in Fig. 5, where the ground electrode is constituted by the gasket 30 with the Y spark point 3| as a nger bentA down from the inner edge of the metallic gasket 30 which is held 'in position against the ledge 20 by the end 29 of the porcelain, when the parts are assembled. Both spark points 23 and 3| may be used together as seen in Fig. 1. They preferably abut against the side of the skirt but do not project beyond its end. Y v

It should be noted that the end 29 of the porcelainsubstantially fills the space above the ledge 2U in order to rmly hold the porcelain in the housing. At 24 an air chamber is formed in the housing I0 around the porcelain I2 communicating with the atmosphere through apertures 25 in the side oi the housing J0. By diminishing the diameter of thc'porcelain below this chamber, or by furnishing longitudinal grooves as at 26, the cooling air can circulate around the greater portion of the body of the porcelain. In the event of the use bon, as 'at 33, Fig. 4, formsin the spark gap on the 5 exposed end of the skirt 21 of the porcelain, between the central electrode head I1 and the ground electrode points 23 and 3| respectively.

' Any excess of such deposit is consumed during the explosions. This deposit of carbon provides a. rough surface or path in the spark gap which has the function of reducing the resistance between the electrodes. It should be noted that the spark points 23 and 3| .substantially contact with the free end of the porcelain skirt. without any open space between them. 'I'his construction helps in' cutting down interference in radio equipped cars.

Itlshould beunderstood that my invention is not limited to the detail and constructionhere shown and disclosed but that those may be varied widely 20 without departing from the spirit of the inven` tion as denedby the claims.`

1. In a spark plug having a metal housing member, an insulator core member seated therein, main and groundl electrodes. an annular ledge at the inner end of said housing member forming a seat for said insulator core member and a metal gasket between the core member and the ledge, a skirtrforming -an axial extension on the inner end of said core member and extending beyond the end of said housing member, a. bore being providedthrough the core member and said skirt. the main electrode lbeing mounted in said bore, an enlarged head on the main electrode seated against the end of saidskirt, the main electrode being constituted by two rods adapted for assembling in said bore from opposite ends of the core member` and provided with interengaging elements at their juncture and being cemented in o position in said bore, a projection 'on said gasket terminating substantially level with said head and forming a horizontal spark gap therewith.

. 2. In a spark plug having metal housing member, an insulator core member seated therein y of substantially cylindrical shape with a, fiat shoulder at its inner end, a tapering skirt forming an axial extension from said shoulder and extending beyond the end of said housing member,

a bore being provided through the core member and the skirt, a main electrode mounted in said bore, an enlarged head on the main electrode seated against the end of said skirt but being flat faced and of smaller diameter than the skirt, an annular ila't faced ledge at the extreme inner end 55 of said housing member forming a seat for said shoulder; and a compressible, dat metal gasket between said shoulder and the ledge and provided with a. spark point adapted to give a horizontal spark gap with said head.

3. A spark plug according to claim 2, in which said spark point is constituted by a linger bent down 'from the inner edge of said gasket and terminating substantially level with said head.

4. A 'spark plug according to claim 2, in which 55 a cooling chamber is' providedin said housing member and communicating with a recessed portion in the core member and extending substan- AUGUST EUGENE ANDERSON. j

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