US1477784A - Spark plug - Google Patents

Description

Dec. 18 1923;

SPARK PLUG M. P. SULLIVAN Filed May 20, 1920 INVENTOR Mddf/Ze? l. Sal/Mm 87 W a? A T ORA/E Patented Dec. 18, 1923.

-UNITED STATES j 1,477,784 PATENT OFFICE.

' IAUBICE P. SULLIVAN, OI NEWARK, NEW JERSEY, ASSIGIiTOB '10 SPLITDORI ELEC- 'I'BICAL COKIAHY, OI NEWARK, JERSEY.

sraax PLUG.

Application filed Kay 20,

To all whom it may concern-.- a Be it known that I, MAURICE P. SULLIVAN, a citizen of the United States, residing at Newark, in the county of Essex, State of New Jersey, have invented certain new and useful lmprovements in a Spark Plu of'which the following is a descrlption, re erence bein had to the accompanying drawing an to the figures of reference In marked thereon.

My invention relates to a spark plug more particularly of the non-grounded type, that is to say, one in which both the electrodes are insulated and brou ht out flosuitable connecting devices. Suc plugs are useful in so-called two-s ark ignition systems, that is to say, where 51cm are two sparks in series in one cylinder. For such purposes it is common practice to use one plu in which 2 both terminals are insulated, suc as in the plug shown and described herein, and a second plug of the usual ty wherein only one electrode is insulated, 0 other being the shell of the plu or the engine itself.

:5 One of the o jects of my invention is to provide a plug of the above typewhich is rigid in construction and relatively cheap to manufacture.

M invention is set forth in a single figure 80 of the attached drawing, which shows a sectional view through various arts of the plug, exce t the central electro e.

In the rawin 1 is a nut corresponding to the usual shel having threads 2 at one end for the purpose of screwing the plug into an engine cylinder. The central hole through the nut 1 carries a tube shaped. insulator 3, preferably of wound mica, thelower end of which rests against a head 4 of the sleeve electrode 5, the interior of which is preferably bored to taper to take a tapered central electrode 6, which is insulated from the interior wall of the sleeve 5 by an insulator 7, preferably of wound mica. The insulator 7 referably extends at its lower end flush wit the head 4 leaving an annular space 8 around the sparking terminal 9 which is fastened to the central electrode 6. The head 4 has fastened thereto a sparking terminal 10'which is formed to co-operate with the terminal 9. Positioned over the tube insulator 3 at its lower end and resting on the head 4 is a rin insulator 11, which is preferably made u o a series of mica washle ors 12, one of which only is'indicated, the

. v l 1920. Serial No. 882,781.

understood of course that the insulators 11 and 13 may be of one piece material of any other suitable kind. It is to be noted that the insulators 11 and 13 rest against opposite faces of the nut 13 thereby holding it in longitudinal position on the tube insulator 3. Resting on the insulator 13 and making contact with the sleeve 5 at 15 is a connecting terminal ring 16 having terminal stud 17 securely fastened thereto .and a nut 18 on the stud 17 for connecting the ignition wire thereto. .Positioned over, the u per end of the insulator 7 and the central 0 ectrode 6 is another insulator 19 which engages the connecting ring 16. The insulator 19 is preferably made up of a series of mica rin one of which is shown at 20 and the was er 21 rests on the; rin 1 9 and a clamping nut 22 engaging threa s 23 on the upper end of the central electrode 6, draws the same securely within the electrode sleeve 5 and through the medium of the head 4 all of the'parts are clamped securely to the nut or shell 1. The terminal nut 24 being used to secure any terminal that may be used between it andthe clamping nut 22.

Havin thus described my invention what I c aim is:

1. In a spark plug, a one piece shell adapted to be screwed into an englne cylinder, said shell carrying a tube shaped insulator within its central opening and a ring of insulating material over the ends of the tube and immediately adjacent both ends of the shell, a metallic electrode sleeve within said tube insulator and having a head for engaging the lower of said ring insulators and a sparking terminal fastened to the head, said sleeve also having a tapered hole passing therethrou h, a tapered central electrode pin fitted within the tapered hole but insulated from said sleeve and having a sparking terminal, spaced away from said pin insulator, a terminal connecting ring seated on the upper of said insulating rin and in annular engagement withsaid meta lic sleeve, an, insulator positioned over-the central in and resting on said connecting ring an means engaging the outer end of the! central pin to draw and hold together all of said parts.

2. In a non-grounded spark plug, a nut threaded at one end for screwing into an engine cylinder, said nut carrying; two conccntrically arranged electrodes, one within the other but insulated one from the other and from the nut, and two spacing insulators engaging the nut 011 opposite faces, said outer electrode having a relatively thick tapering head; a terminal connecting ring in electrical engagement with the outer of said electrodes and resting on the upper of said spacing insulators, an insulator above said ring, the inner surface of said outer electrode as well as the inner electrode being tapered,

and means on the outer extremity of the inner electrode for drawing said tapered portions into normal 0 erative position, the insulator between said concentrically arranged electrodes extending substantially fiush with In testimony 'whereof, I afiix my signature.

MAURICE P. SULLIVANw

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