US2747122A - Spark plugs - Google Patents

Description

May 22, 1956 E. G. BOOTH, SR

SPARK PLUGS Filed May 6, 1953 IN VEN TOR. 00

EmeszG i128:

ATTD RN EYB SPARK PLUGS Ernest G. Booth, Sr., Tampa, Fla.

Application May 6, 1953, Serial No. 353,405

1 Claim. (Cl. 313-124) This invention relates to an internal combustion engine, and more particularly to a spark plug for such an engine.

The object of the invention is to provide a spark plug which includes a pair of electrodes whereby in the event one of the electrodes becomes grounded, the other electrode will continue to function to provide spark for igniting the fuel mixture.

Another object of the invention is to provide a spark plug which includes a pair of electrodes which will intensify the spark provided and which will also insure that the spark plug will continue to function even though one of the electrodes may fail or become grounded, the spark volume produced by the spark plug of the present invention being increased over spark plugs only having one electrode and due to the construction of the present invention there will be no chance for carbon to form since the explosions will blow off any tendency for carbon to form on the electrodes.

A further object of the invention is to provide a spark plug which is extremely simple and inexpensive to manufacture.

Other objects and advantages will be apparent during the course of the following description.

In the accompanying drawings, forming a part of this application, and in which like numerals are used to designate like parts throughout the same:

Figure 1 is a side elevational view of the spark plug, constructed according to the present invention.

Figure 2 is a top plan view of the spark plug.

Figure 3 is a sectional view taken on the line 3-3 of Figure 2.

Figure 4 is a longitudinal sectional view through the body member showing the pair of electrodes mounted therein.

Figure 5 is a longitudinal sectional view through the support member showing the terminal therein.

Figure 6 is a longitudinal sectional view through the base.

Referring in detail to the drawings, the numeral 10 designates the base of the spark plug which may be fabricated of any suitable conducting material, and the base 10 includes an upper annular flange 11 that is threaded interiorly, Figure 6. Suitable flat faces 12 are arranged on the outer surface of the flange 11 whereby a suitable tool such as a wrench can be arranged in engagement with the faces 12 for inserting and removing the base 10 from the engine. The base 10 is further provided with a longitudinally extending opening or bore 14, and there is provided further a lower cylindrical portion 15 which is threaded exteriorly. Extending from the cylindrical portion 15 is a pair of inwardly facing ignition contacts 16 which are spaced apart from each other.

The numeral 17 designates a body member which may be fabricated of a suitable insulating material such as porcelain, and extending longitudinally through the body member 17 is a pair of spaced parallel conducting electrodes 18. The electrodes 18 have their ends extending beyond the end of the body member 17. Arranged inter- 'nited States Patent 0 mediate the ends of the body 17 and formed integral therewith or secured thereto is an annular shoulder 19, there being an enlarged cylindrical portion 20 contiguous to the shoulder 19, Figure 4.

In Figure 5 there is shown the support member which is indicated generally by the numeral 21, and the support member 21 may be fabricated of a suitable insulating material which may also be transparent such as Pyrex glass. The support member 21 includes a lower threaded portion 22 for engaging the threaded flange 11 of the base 10. A conducting terminal 23 includes an intermediate threaded portion 24 for engaging the support member 21, and the inner end of the terminal 23 is indicated by the numeral 25. Provided in the support member 21 is a space or chamber26, and it will be seen that when the parts are assembled as in Figure 3 the inner end of the terminal 25 is spaced from the inner ends of the electrodes 18 so that the spark will of necessity have to jump from the end portion 25 of the terminal 23 to the pair of electrodes 18. Thus, there will be provided an increased volume of spark between the outer ends of the electrodes 18 and the contacts 16 and also in the event one of the electrodes becomes grounded or inoperative, the other electrode will still provide sufficient spark to ignite the fuel mixture.

A portion of the outside of the base 10 may be knurled as at 27 to facilitate manual handling of the spark plug, Figure 1, and an inner portion of the support member 21 may be recessed as at 28 for snugly receiving therein the enlarged portion 20 of the body member 17 when the parts are assembled together.

From the foregoing it is apparent that a spark plug has been provided which includes a pair of the electrodes 18 so that there will be an intensified spark provided. Also, it will be seen that the inner end of the terminal 23 is spaced from the electrodes 18 so that the spark must of necessity pass from the inner end portion 25 to the pair of electrodes 18. Thus, there will be a spark provided between each of the outer ends of the electrodes 18 and the contacts 16 so that an intensified spark will be produced. In case one electrode becomes fouled up or grounded the other electrode 18 will still function and the space between the terminal 23 and electrodes 18 causes the spark to pass down both of the electrodes 18 and then jump to the contacts 16. Further, in the event that one electrode 18 becomes grounded, the other electrode will spark at the point with a concentrated or heavy condensed spark since all of the current will pass down the remaining electrode. The present invention will increase the spark volume by actuating the spark in the partial vacuum chamber 26 to thereby cause the spark to become white hot. The pair of electrodes 18 will both discharge at each alternation of current and due to the closed bottom there will be no carbon formation since each explosion will keep the carbon blown 01f. The transparent Pyrex support member 21 permits visual observation of the interior of the spark plug.

I claim:

A spark plug comprising a generally cylindrical base fabricated of conducting material and including an upper outwardly extending annular flange of increased diameter and having interior threads, said flange having flat faces on its outer surface for engagement by a tool, there being a longitudinally extending bore extending axially through the entire length of said base, said base having a lower cylindrical portion of decreased diameter provided with exterior threads, a pair of inwardly facing ignition contacts extending from said last named cylindrical portion and in electrical contact therewith, a body member fabricated of insulating material having a portion positioned in the bore of said base, an end portion of said body member projecting out of the end of said base and remote from said last named cylindrical portion, a pair of spaced parallel electrodes extending longitudinally through said body member, the ends of said electrodes extending beyond both ends of said body member, an annular shoulder arranged intermediate the ends of said body member, there being an enlarged cylindrical portion on said body member contiguous to said shoulder and of greater diameter than said shoulder, a support member fabricated of insulating material, said support member being transparent and including a lower threaded portion for engaging the threaded flange of said base, said transparent support member permitting visual observation of the interior of the spark plug, a conducting terminal including an intermediate threaded portion for engaging said support member, the inner end of said terminal being spaced from the inner ends of said electrodes and in close proximity thereto so that the sparks will have of necessity to jump from the end portion of the terminal to the pair of electrodes whereby there will be provided an increased volume of sparks between the outer ends of the electrodes and the contacts and whereby in the event one of the electrodes becomes grounded or inoperative, the other electrode will provide heavy condensed sparks, there being a chamber in said support member in which said terminal terminates, a portion of the outside of said base being knurled to facilitate manual handling of the spark plug, an inner portion of said support member being recessed for snugly receiving therein the enlarged cylindrical portion of said body member.

References Cited in the file of this patent UNITED STATES PATENTS 1,073,270 Meaker Sept. 16, 1913 1,131,115 Carpentier Mar. 9, 1915 1,385,529 Ellis July 26, 1921 2,487,319 Ellis Nov. 8, 1946 FOREIGN PATENTS 820,981 France Aug. 17, 1937

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