US1564645A - Spark plug - Google Patents

Description

Dec. 8, 1925.

` 1.564.645 J. M. THOMAS SPARK PLUG Filed Nov. 30. 1923 /NVE/vo/P JESSE M, #forms /0 wg mw Arrow/ns Patente-d Dec. 8, 1925.

isaias- UNITED STATES P'iA-:TENT-` OFFICE.

JESSE M; THOMAS, 1OFl-"hll LAWN, MISSOUR, ASSIGNOR OF VONE-'lI-IIRD 'TO` WJLLIAM D. GIEtUEILLIEv,V OF ST. `ll'.i0llV]S, MISSOURI.

SPARK PLUG. i

Application filed November 30, 1923.5- Seral No. 677,678.

fo all whom` it may concern.'

Be it known that I, JnssnM. THOMAS, a citizen of the United States of America, a resident of Pine Lawn, in the county "of St. Louis, State of Missouri, have inventedfeertain newy and useful lmprovementsinV Spark Plugs, of which thel following 'is 1 a full,

clear, and exact description, reference/.being .1 had to the accompanyingdrawing, formingA- a part of this specification.`

This invention relatesv to` improvements.

in electric ignition devices,` commonly called spark plugs, for internal combustion engines,'and it consists in the novel features, 'structure and combination of parts'hereinafter describedand particularly pointed out in the claims.-

The object of the invention is, generally speaking, to provide a spark plug which may be conveniently*manufactured and composed of a limited number of parts, and' in operation be highly efficient and reliable, and more specifically the object of the invention is to provide a spark plugjjcomprising a main exterior casing and an interior unit including a core, or body, within said main exterior casing. The main exterior casing is screwed into a wall of an'engine cylinder, and the interior unit is so arranged that it may be rotated axially relative to said main exterior casing without moving said main exterior casing, thus rendering itpossible' to secure the spark plug in place in a wall of an internal combustion engine after. which the interior unit may be rotated independently of the main exterior casing so "that a predetermined portion of said interior unit' may be faced toward a designated part of said internal combustion engine..

The spark plug disclosed in the present application is particularly intended for use with the improved shield for spark plugs disclosed by me in Aan application for United States Letters Patent iiled November ll, 1022, and bearing Serial Number 600,265;

`With the foregoing and other objects in view, the invention comprises. the novel construction, combination "and arrangement of parts hereinafter more specifically 'described and illustrated in the accompanying drawings wherein is shown the" preferred embodiment of the invention; However,'it is to be understood that the invention comprehends changes, variationsand modifications which come within the scope ofthe claims hereunto appended;

Figpl is a Afront elevation of myimproved,

Fig. TV is laperspective View of theshield I associated with. iny improved spark. plug.i ln the drawing, A designates my improved spark plug` which comprises a main 'exterior casuigfB and an" insulatinggcore, orbody, C. The main exterior casing B is provided with a threaded lower portion D anda non# circular wrench-receivingfportion E wherebylsaid main exterior casing may be screwed into an internallyV threaded' opening in a wall of an internal vcom'bustioi'i engine.v The main exterior casingB is, as'usual, formed of metal, and 'saidl main exterior casing is provided .with internal screw threads F, as shown indrig.V Il. A main exterior' casing'B is a horizontal annular shoulder l, whichfis arrangedbelow the internall screw threads F justinentioiied.

Located within. the main exterior Acasing B isfan interior"core4supporting device 2,Y

said supporting.device` being constructed of metal and being inthe form of a shell havingan' elongated cylindricalupper portion 34 and ai lower cylindrical portion 4.' An annular horizontal-wall. 5 connects the annularwallof the upper portion of thc shelll with'the anniilai'wvall of the lower portion thereof. When the'spark plug is assembled' the 'lower face of the horizontal annular' wall 5 ofthef core-supporting de-r vice 2 restsupon the shoulderl within the main exterior casing B, there'being a gasket 6 interposed between the opposed faces of said shoulder and' said wall.

Theinsulating core 'or bodyC is arranged partially within the main exterior casing B", said core or body being extended above ing core'or body C is provided with an en'- larged portion C', which is arranged within the enlarged upperportion 3 of the coresupporting'device 2, as shown in F-igj IIJ In assembling the spark' plugyan annular gasket? is'interposed between the lowerv face of theenlarged portion C" ofthe core'l C andthe top" face 'of the'horizontal vwall 5y ofthe core-supporting-'device 2? Theupper Arranged within the end of the core-supporting device 2 is provided with a comparatively thin annular wall 2', which secures the core C to the coresupporting device 2. This annular wall is bentI inwardly so that it overlaps the outer portion of the enlarged portion of the core C, as shown in Fig. II. An annular gasket 7 is interposed between the bent-over annular wall 2 and the top face of the enlarged portion of the core C. The reason for the gaskets 6, 'T and 7 is that the core C is made of an insulating material, such as porcelain, which is usually easily broken, and the gaskets form cushions between said breakable body and the hard metallic parts with which it contacts. An electrode Gr passes through the 'core C and extends downwardly therefrom, said electrode being provided with-a binder nut G by which a conductor terminal may be held in contact with said electrode.

8 designates a threaded bushing which is provided with external screw threads. In the assembled spark plug the threaded bushing 8 is screwed into the interiorly threaded upper portion of the main exterior casing B, the lower end of said bushing bearing against an annular face 9 of the core-supporting device 2.

S designates a shield which is extended upwardly into t-he main exterior casing B and secured to the lower cylindrical portion et of the core-supporting device 2. The shield S comprises a substantially cylindrical member preferably constructed of spring metal, the annular-wall of said member being split, as shown most clearly in F ig. V, whereby said member may expand and contract. The shield S is provided with a pair of outwardly extending ears l() which are in contact with the lower end of the main exterior casing B, when said shieldhas been extended the proper distance into said main exterior casing, and 'said shield is provided with a pair of angularly projected members' ll which are located at the lower end of said shield. Located in the wall of the shield S is an air opening l2, said air opening being provided with an air deflector 13. The air opening and air deflector are formed by cutting a U-shaped slit in the wall of the shield and bending the metal within said U-shaped slit inwardly to form the air detlector. Located in the wall of the shield S adjacent to the upper end thereof is a pair of apertures 1% arranged diametrically opposite to each other,` and arranged on the lower portion 4L of the core-supporting device 2 is a pair of pins l5, said pins l5 also being located diametrically opposite to each other. To attach the shield. S to the spark plug the upper end portion of said shield is introduced into the lower portion of the main exterior casing Il. The shield is then moved upwardly until the lower end of the coresupporting device 2 passes into the upper end of the shield. The ecges of the pins 15 are slightly rounded so 'that when the upper edge of the shield. contacts with said pins said shield will be spread so that said upward movement of said shield relative to said pins may continue until the ears l() contact with the lower end of the main exterior easing B. lVith the shield in the position described a rotary movement of said shield will bring the apertures lei to positions where they register with the pins l5, thus permitting said pins to extend into said apertures whereby said shield is firmly fixed to said core-supporting device 2. The angularly arranged projections 1l function as YelectrodesA and when the spark plug is fully assembled with the shield in place, spark 0aps are provided between said angularly arranged. projections ll and the electrode G, as shown in l? ig. I.

In the use of a spark plug provided `with the shield shown and described herein, earbureted air will be drawn througli the air opening l2 and will be de'tlected by the deileetor 13 against the liring points of the electrodes to keep said tiring points of the electrodes clean. To obtain the best results it is necessary that the open portionof said shield be faced toward the inlet valve of the internal combustion engine with which the spark plug is associated. Heretofore it has been necessary to screw the ordinary spark plug into the opening in the wall of the engine and after said spark plug was firmly seated to place iark ci' some sort on that portion of the upper portion of the spark plug" which faced the .inlet valve of the engine. The spark plug would then be removed from the engine and the shield would be attached to said spark plug so that the open portion of said shield was en the same side of the spark plug as the mark. then the spark plug was again placed in the engine after the procedure just recited the open port-ion of the shield would be properly positioned relative to the inlet valve of the engine. My improved spark plug is provided with a mark such as that indicated in Fig. I by the reference character H. The apertures la in the wall of the shield S and the pins l5 on the portion l of the core-supporting device 2 are so arranged that the open portion of said shield will be on the same side of the core as the mark I-I when said shield is secured to said core-sup` port-ing device. To locate my improved spark plug properly within an engine cylinder, the assembled spark plug is screwed into the internally threaded opening in a wall of the engine as would any other spark plug. It lmay then be found 'that Ythe marl; Il and consequently the open portion of the shield S are not 'facing the inlet valve oiv the ei'igine. In that event it is only necesllO sary to unscrew the threaded bushing o so that the pressure of said bushing is removed from the face 9 of the corc-si'ipporting device 2. It will be remembered that the core-supporting device is'securely fixed to the core C so that said core may not rotate while said core-supporting device is gripped between the lower end of the bushing S and the annular shoulder i, but when the pressure has been relieved by unscrewing the bushing, the'core C, core-supporting device 2 and shield S may be freely rotated as a single unit. The core may therefore be rotated until the mark H- faces the iniey valve of the engine, in which position the shield S will be properly positioned with relation to said inlet valve. After the core C has been properly positioned the threaded bushing 8 will be screwed downwardly until the lower' end thereof' bears firmly against the core-supporting device 2, whereby said core-supporting device will be firmly gripped between the lower end of said bushing and the shoulder l, thus preventing accidental movement of said core. lt will be noted that the lower end of the bushing 8 bears against the metallic core-supporting device 2, consequently there is very little danger that the core C will be cracked when said bushing is screwed downwardly to clamp said core in place.

I claim:

l. A spark plug comprising an exterior member adapted to be secured in a wall of an engine, an interior unit within said exterior member, said interior unit including a core, an electrode supported by said core and a shield provided with a second electrode, said shield being arranged adjacent to the lower end of said lirst mentioned electrode and being provided with a deflector adapted to deflect carbureted air against the firing points of said electrodes, said interior unit being rotatable axially relative to said exterior member and means whereby said interior unit may be retained in a fixed position relative to said exterior member.

2. A spark plug comprising an exterior member adapted to be secured in a wall of an engine, an interior unit within said exterior member, said interior unit comprising a core, an electrode supported by said core, a core-supporting device and a shield provided with a second electrode, said shield being arranged adjacent to the lower end of the first mentioned electrode and being removably attached to said core-supporting device and said shield being provided with a de'iiector adapted to deect carbureted air against the firing points of said electrodes, said interior unit being rotatable axially within said exterior member, and means whereby said interior unit may be retained in a fixed position relative to said exterior member.

3.A spark plug comprising` an exterior i member adapted ,to be secured in a wall of an engine, an interior unit within said exterior member, said interior unit comprising a core, an electrode supported by said core, a core-supporting device to which said core is lixed and a shield provided with a second electrode, said shield being arranged adjacent to the lower end of said first mentioned electrode, and means whereby said shield is removably attached to said coresupporting device, said means comprising pins arranged on said core-supporting device which pins are adapted to enter apertures in the wall of said shield, said interior unit being rotatable axially within said exterior member and means whereby said interior unit may be retained in a fixed position relative to said exterior member.

el. A spark plug comprising an exterior member adapted to be secured in a wall of an engine, an interior unit within said exterior member, said interior unit comprising a core, an electrode supported by said core, a core-supporting device to which said core is fixed, a shield provided with a second electrode, said shield being arranged adjacent to the lower end of said first mentioned electrode7 and means whereby said shield is removably attached to said coresupporting device, said means comprising pins-arranged on said core-supporting device which pins are adapted to enter apertures in the wall of said shield, said shield being provided with an aperture through which carbureted air is drawn against the firing points of said electrodes, said interior unit being rotatable axially within said exterior member, and means whereby said interior unit may be retained in a fixed position relative to said exterior member.

5. A spark plug comprising an exterior member adapted to be secured in a wall of an engine, an interior unit within said exterior member, said interior unit comprising a core, an electrode supported by said core, a core-supporting device to which said core is fixed, a shield provided with a second electrode, said shield being arranged adjacent to the lower end of said first mentioned electrode, and means whereby said shield is removably attached to said coresupporting device, said means comprising pins arranged on said coresupporting de-` vice which pins are adapted to enter apertures in the wall of said shield, said shield being provided with an aperture through which carbureted air isl drawn against the firing points of said electrodes, and a deflector on said shield adjacent to said aperture, said interior unit being rotatable axially within said exterior' member and means whereby said interior unit may be retained in a xed position relative to said exterior member.

llO

6. A spark plug comprising an eXterior member adapted to be secured to a wall of an engine, an interior unit Within said exterior member, Said interior unit including a core, an electrode supported by said core, :L second electrode, and a shield, said shield being larranged adjacent to the lower end of the first mentioned electrode and being provided with a deflect-or adapted to deflect earbureted air against the firing points of seid electrodes, said interior unit being rotatable axially relative to said exterior member, and means whereby said interior unit may be retained in a fixed position relative to said exterior member.

In testimony that I claim the foregoing I hereunto affix my signature.

JESSE M. THOMAS.

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