US1238990A - Self-cleaning spark-plug. - Google Patents

Description

W. H. COTTDN.

SELF CLEANING SPARK PLUG. APPLICATION nun-Aug; 16, ms.

1,238,990. Patented Sept. 4, 1917.

UNITED STATES PATENT OFFICE.

WALTER H. COTTON, OF CHICAGO, ILLINOIS,

DIG 00., F HURON, SOUTH ASSIGNOB TO OLD DUTCH MANUFACTURE DAKOTA, A CORPORATION.

SELF-CLEANING SPARK-PLUG.

Specification of Letters Patent.

Application filed August 10, 1916. Serial No. 115,183.

devices for internal combustion engines and contemplates a construction by which a vigorous movement of the gases over'the electrodes and adjacent parts is insured. The object of the invention is to provide a spark plug for explosive engines which shall be of simple construction but reliable in operation under all circumstances.

The invention is exemplified by the structure to be hereinafter described and which is illustrated in the accompanying drawings wherein,

Figure 1 is a sectional view showing ofie form of the section being indicated by the line 1'1 on Fig. 3, and some of the parts being shown in elevation;

Fig. 2 is a side elevation spark plug;

Figs. 3 and 4 are a top plan view and an inverted lan view, respectively, and

Fig. 5 1s a detail sectional view of an explosive engine showing one way in which the improved spark plug maybe applied thereto, the spark plug being shown in elevation. v

The construction preferably comprises a chambered body having a contracted tubular stem 11 at one end. The stem 11 may be externally threaded for introduction into the spark plug socket 12 of an explosive motor, as 13, in a well known manner. One of the electrodes, as 14, is mounted at the outer end of the tubular stem 11 andprojects over the bore 15 of the stem to a point adjacent its axis, as usual. The other electrode, as 16, may also be of familiar construction. As shown, it takes the form of a straight rod or wire, axially rranged with reference to the stem 11, diid extending upwardlythrough the body 10, with the greater portion of the wire cmof the improved of the improved spark plug, the plane bedded in an insulating cylinder 17, ofhard material, as porcelain, and with the usual binding screw 18 provided at the upper end.

In the preferred form of construction, as illustrated in the drawings, the electrode 16 and its insulating cylinder 17 are removably mounted to permit of their being separated from the body 10.

For this purpose the insulating cylinder 17 is formed with an annularly enlarged portion 19 intermediate its ends providing oppositely facing shoulders 20 and 21.. To provide a compact arrangement, the cover 22 of the body 10 is formed with a depressed central portion 23 which servesas a socket for receiving the enlarged portion 19 of the insulating cylinder 17. Under these circumstances the floor of the socket 23 is apertured as at 24, to permit the. passage of the electrode 16 and the part of the insulating cylinder 17 which is below the enlargement 19. In assembling the parts, gaskets 25, 26, are applied to the two shoulders 20 and 21 and a screw plug 27 is entered in the socket 23 over the uppermost gasket, as

For convenience in manufacture, the cover 22 may be formed from a separate piece but it is permanently united with the side walls of the body, as by welding.

When the parts are proportioned about as shown, the chamber of the body 10 about the socket 23 constitutes a pocket into which the gases are compressed at intervals and from which they escape by expansion when the pressure is released. As the space surrounding the insulating cylinder 17 within the bore of the stem 11 provides only a re stricted passage for the gases to and from the body chamber, the movement of the gases over the surface of the insulating cylinder 17.adjacent the exposed part of the electrode 16 will be sufiiciently vigorous to provide that this surface will be swept clean of any deposit of material likely to cause a path for the electric charge. Ger.- tainty in operation is thereby insured.

I claim as my invention,

1. A s ark plug having a metal body and a core 0 insulating material inclosd in the Patented Sept. 4, 1917.

body. such body being provided with an annular chamber surrounding the core and stantiel length, and a pair of coo crating electrodes, one thereof projecting mm the core.

2.- A spark plug having a chambered body and a tubular neck open at its outer end, the bore of the neck communicating with the chamber of the body and being of less diameter than such chamber, a core of insulating material extending into the bore of the neck and forming With the Wall thereof a restricted annular passage of substantial length, and a pair of cooperating terminals one thereof projecting through the core.

3. A spark plughaving a hollow metal body open at its inner end, the inner end of the chamber of the body being enlarged, a core of insulating material on the axis of the body and extending a substantial distance into the restricted portion of the body chamber and forming with the wall thereof an annular axially directed passage from the enlarged portion of such chamber, and a pair of cooperating electrodes one thereof projecting from the core.

WALTER H. COTTON.

Images