US2221537A - Spark plug - Google Patents

Description

Nov. l2, 1940. c. R. BUENING 2,221,537

SPARK PLUG Filed July 14, 1939 gif/19 Z @BR/097mm;

INVENTOR CAW/P1155 .5v5/WN@ BY Q MA ATTORN EY Patented Nev. 12, 1940 2,221 :on

das s SPARK PLUG Charles B. Buening, Milwaukee, Wis., assignor to Globe-Union Inc., Milwaukee, Wis., a corporation oi.' Delaware Application July 14, 1939, Serial No. 284,393

13 Claims. (Cl. 12S-169) This invention relates to an improvement in which underlies the action of such structure is spark plugs of the type wherein the insulator of not clearly and fully understood, but it has been the central electrode, usually in the form of a found that spark plugs so constituted, even body of poreclain or the like, is assembledwlth though tending to leak slightly when ilrst asand hermetically sealed and secured to the outer sembled, will, if put in an engine and subjected metallic bushing or shell which carries or functo use for several days, seal up. Another chartions as the grounded electrode, and which is acteristic that may be mentioned is that after threaded into the opening provided therefor in plugs of this type have been tightened up and the engine. allowed to stand for some time, or operated in In structures of this type, it is necsary to eian engine, the metal '0f the gasket apparently lg fect a. hermetic seal between the insulator and ows into the pores of the insulator to such an the metallic bushing -or shell, and for this purextent that if the plug Were disassembled it pose it has been common practice to employ a would be practically impossible to remove the gasket located relatively inwardly of the strucgasket from the insulator.

ture. In types of spark plugs where the parts are The invention mayv be embodied in Various 15 maintained in assembly by the use of a packing types of spark plugs. In the type of spark plug nut or gland, an outer gasket is also employed where the insulator is held assembled with the which serves not so much as a sealing device as a shell by means of a packing nut, the cadmium cushioning and locating device. Reliance for the plated Sealing gasket iS eembrled With the Outer zo required seal is placed upon the inner gasket. locating and CilShOnirlg gasket in a special man- One of the very common faults of most spark ner, in that the Outer CuShiOnllg 0r IOCatng EES- plugs is leakage of the inner gasket, the one reket is so constituted as to minimize the translied upon to effect the seal. Such leakage permission of any turning movement from the packmits hot gases to traverse the gasket, resulting in ing nut to the insulator. This action is especially g5 rapid deterioration of the gasket, thereby inadvantageous for the reason that .the cadmium 25 creasing the leakage and consequently involving plated inner seal gasket not only effects this lossvoi compression and power in the engine. In selaing function but also locks or holds the inthis type of construction as heretofore devised, Sulator against turning movement HOWeVer, the plugs may be assembled so that they do not many 0f the imperium@ advantages of the PreS- leak originally, but, due tothe diierential expane'nt invention are realized in other types oi.' 30 sion of the various parts, leaks develop as the structurefor example, with the so-called oneplugs are heated up in service. To overcome this piece Spark plug COIiStrllCtOrl. Tibet iS the type diiliculty, it has been common practice to exces- 0f Structure Where a Decking nur 1S D011 employed, sively tighten up the assembly, and this results in but the insulator s held assembled with the methe setting up of excessive stresses in the insutallic shell or bushing by crimping or displacing 35 lator and squeezngor distorting the gasket, to the metal of the 'bushing over the upper end of such an extent that a, two-piece plug cannot; the insulator. In thS type 0f Structure the cadlater be disassembled. mium plated inner gasket exerts this desirable One'oi the important objects of the present insealing function, relieves the portions of the ino ventionis to provide a construction which eiIects sulator least adapted to bear the same oi ex- 40 Such 8 Sas-tight or hermetic S681 at the inner cessive stresses, and holds it in place. gasket that the plugs do not leak when cold Approximately the same results may be 0band i150 d0 not develop leak? when they ere tained by tin-plating or lead-plating the inner heated' This result 1S accomplished with a mm' sealing gasket but it has been found in actual 5 lmum tightening or squeezing force on the inner practice that admium lating is the b t 5 gasket so that excessive stresses are not set up A furthe b. t f h 1 .es in the insulator. Furthermore, such stresses as r. o Jee o e nventlon 1s to 1m." are set up are directed way from the portions prove, simplify, and compact a structure of this .of the insulator least adapted to withstand the character in such manner as to secure the desame; sired seal While ,arf-:indiens inglny, damage, or The accomplishment of the Obs-e535 and adover-stress lo oi' the component parts employed. vantages so far pointed to is realized principally i still further object of the invention is to by cadmium plating the inner or bottom gasket, provide a structure having the advantages menthe one relied upon to effect the hermetic seal of tioned, and which is simple durable con u this spark plug assembly. The phenomenon y struction, reliable and effective in operation, and 5s easy and comparatively inexpensive to manu-V facture. Otherobjects and advantages resideinoertain novel features of construction. arrangement, and 5 combinatlonofparmwhichwillbehereinaiter more fully described and particularly pointed outintheappendedclaimareierencebeinghad to the accompanyigdriwing'hmorming a part ot thisspealiication. V 1o ngurclisavlewpartly'invermdi'asnetric crosssectiomandpartlyinsidealevation, showingasparkplugconstructedinaccordancewith the present invention.

I'igureisafragmentarydetailviewon 1| enlargedscaleshowingtheuppergaskstoi'the spark plug, partlyin crcssseotion, andfpartlyin elevation.

Pigure3isaviewaimilario1'igure2,illustrat ing the structure o! the lower gasket as it approximatelyappearsafterithasbeeninuseor compressed.

Figureaisadetailedpermctiveview ofthe UPN gasket:

Flgureisadetailedperspectdveviewoi'the l lowergasket; and

l'igureisafragmentaryviewlncrosssecon showing the lower gasketasit is constituted betorleassemblyanclcompression.` o A,

The inventionwillbeillustrated and described as umbodlodmtnetypoofoporkpmwmonm ametallicshellorbushing.aninsulatingbody nut for maintaining these parte but. as indicated. it is o! course susceptible of t in the Il one-piece structure previously described.

Referring to the drawing, the numeral Il desighates the buhlnlol' metallic, shell-like bodyvoi' theaparkplug,whichisexternallythreaded.as`

at il. at its lower audio adapt it to be threaded Q into the Wellink IIll'flvided therefor in the cylinderheadoitheengine (notshown). Theinsulltnt. usually in the form o! a body of porcelain, um at ILiaaslcmbledwith the metailic body Il.' This insulator. as usual, sur- Internallythemetallicbody ills-provided with an an upwardly facing. annular shoulder or gasket seat 2l. A gasket!! rests on this seat in the assembly and is engaged by a downwardly facing, annular shoulder or gasket seat 22 formed on the porcelain boch of the insulator l2. Above the gg seats 2l and 22 the porcelain body is provided with an upwardly facing, annular shoulder or gasket seat 2l engaged by a second gasket 24. The lower end ot the packing nut i1 is formed with a downwardly facing annular shoulder or 10 gasket seat 2l. which engages the top side of the body o! the gasket 24. 'Ihe gasket 24 is formed with an integral neck portion 28. which is accommodated in an internal annular recess "in the lower end oi the packing nut l1.

1g The present invention proposes to constitute The lower end of v thegasketll oianannealedorsoltmetalbody Il, usually of copper, although it may be oi any metal of high heat conductivity, auch ag silver. save that metal such as silver involves a considerable item of expense. Where the body is con- 5 stituted oi' copper, it is coated with a metallic coating or plating Il oi! cadmium. nickel. tin. or lead ,or the like, applied thereto by electrode deposition. or by dipping.

Thebodyporidonandtheneckoitheupperl gasket 24 are constituted ot relatively hard metal. usually brass. but which may be steel. copper. aluminum. or some suitable alloy. Its essential characteristicinthistypeoi'structureisthatit be appropriately hara. ons that 1t be Iprovided il withacoatingoriilm notalubricantsuchaa wax, paraiiin, oil. or other friction-reducing ma terial.'

In addition tothe foregoing. the seat or shoulderasontneporoemnboay unnnootnorl glased,whereastheseatorshoulder thereof is rough. that is unglased or bisque. t

With a construction o! this character. when theparts are assembled, and the packing nut Il is tightened, the mnt il, and its cooperating I gasket seatawill nrst operate to lmld the insulator i2 againstturning, and thisaction ori-tbe part of the element is aided by the capacity present in the upper gasket 24 and its cooperating seat n for suppose. 'rho tightening potion or vtheuutisthustranlli'erretilargelynsaatraightaxial pressure. or as a pressure parallel to the axisot the insulating body, and the tendency to setuptoraionortwistingstralnaorstrainsin the aut-.to or loooud portions or the insulator u leastliabletowithstandthemareallverystw' stantially reduced or minimised. The result is a permanent gas-tight or hermetic seal between the gasket 2| and its seats. and a substantial reductioninstraininallportinnsoitheplug. Since al no parts o! the spark plug are over-stressed, or subjected to any great concentration of stresses. the plug in use is better able to withstand impacts or mechanical lblows or shocks, and also the andstrainsinddenttoseverechangeain ,al temperature. y I'he plated inner gasket 2i. when pressed betweenitsaeatsinthe'assembly providesthemost eii'ective hermetic seal, and in so doing it flows upwardlyandawayiromthejunctureoithetaperedlowerportlonoitheinsulatoranditsrela` tivelythickbody. Thisisimportantasitralleves this juncture, a part leas adapted to withstand stress oi' any und incidental to the seal desired.

The invention its marked utility when embodiedinasparkplugoithetypeillustrated. but many of the advantages may be realisedin other designs. For example. in the one-piece mechanically crimped and electrically heated or c! compressed type of spark plug. or the one-piece mechanically twisted under vertical pressure, all oi the desirable characteristics of the gasket Il anditsplatingcrcoatingarerealised.

While I have shown and described one construction in which the invention may be advan tageouslyembodieditistobeunderstoodthat the construction shown has been selected merely for the me ot illustration or example. and that various changes in the sise. shape. and ar- 70 rangement of parts may be made without departing from the spirit of the invention or the scope oi' the subjoined claims.

I claim:

Lasparkphigolthecbaueterdeseribadil comprising a metal shell having an upwardly facing inner gasket seat, an inner gasket engaged with said seat, an insulating body having a downwardly facing gasket seat engaged with said gasket, said insulating body having an upwardly facing outer gasket seat, an outer gasket engaged with said outer gasket seat, a packing nut threadedly connected with said shell and having a downwardly facing seat engaged with said outer gasket, said inner gasket being constituted of relatively soft metal having a coating adapted to have gripping and hermetic sealing engagement with the adjacent gasket seats to hold the insulated body against turning, said outer gasket being constituted of relatively hard metal and having an anti-friction coating designed to permit slippage between the outer gasket and its cooperable gasket seats.

2. A spark plug of the character described comprising a metal shell having an upwardly facing inner gasket seat, an inner gasket engaged with said seat, an insulating body having a downwardly facing gasket seat engaged with said gasket, said insulating body having an upwardly facing outer gasket seat, an outer gasket engaged with said outer gasket seat, a packing nut threadedly connected with said shell and having a downwardly facing seat engaged with said outer gasket, said inner gasket being constituted 0i soft metal having a coating of cadmium, the downwardly facing inner gasket seat of the insulated body being unglazed whereby the inner gasket when compressed between its seats will hermetically seal thereunto and hold the insulating body against turning, the outer gasket being constituted of a hard metal having a lubricating lm thereon, the upwardly facing gasket seat on the insulating body being glazed whereby when the packing nut is tightened the outer gasket may slip relative to its seats to permit the packing nut to compress the inner gasket with straight axial pressure.

3. A spark plug of the character described comprising a metal shell having an inner gasket seat, an inner gasket of soft gripping as well as hermetic sealing material e.engaged with said seat, an insulating body having an inner gasket seat engaged with said inner gasket and also having an outer gasket seat, a hard outer gasket having lubricated gasket seat-engaging surfaces, and a packing nut threaded to the shell and having a gasket seat engaged wit'h the outer gasket.

4. A spark plug of the character described comprising a metal shell having an inner gasket seat, an innner gasket of soft gripping as well as sealing material engaged with said seat, an insulating body having an inner gasket seat engaged with said inner gasket and also having an outer gasket seat, a hard outer gasket having lubricated gasket seat-engaging surfaces, and means interconnected with the shell and having a gasket seat engageable with the outer gasket to effect compression of both gaskets and cause the inner gasket to hermetically seal with and hold the insulating body against turning movement relative to the shell.

5. A spark plug of the character described and including a metallic shell, an insulating body, an inner non-ferrous metallic gasket having a soft metal coating, and means for maintaining the body and shell assembled and compressing the inner gasket into hermetic sealing engagement with the insulating body and the shell.

6. A spark plug of the character described comprising a metallic shell having an outwardly and outwardly upwardly inclined inner gasket seat, an insulating body having a portion of relatively large diameter and an inner tapered portion, and provided with an inwardly and downwardly inclined shoulder at the juncture of said portions, a non-ferrous metallic gasket having a soft metal plating interposed between said seat and said shoulder, and means for holding the shell and body assembled and for forcing the body inwardly of the shell to compress the gasket between the shoulder and the seat and cause it to flow away from said juncture whereby to effect a hermetic seal between the body and the shell without application of stress to said juncture.

7. A spark plug of the character described comprsing a metal shell having an upwardly facing inner gasket seat, an inner gasket engaged with said seat, an insulating body having a downwardly facing gasket seat engaged with said gasket, said insulating body having an upwardly facing outer gasket seat, an outer gasket engaged with said outer gasket seat, a packing nut threadedly connected with said shell and having a downwardly facing seat engaged with said outer gasket, said inner gasket being an annealed soft metal such as copper having a coating or plating of cadmium or the like so as to hermetically seal the parts and hold the insulating body against turning when compressed against its seat, said outer gasket being constituted of a relatively hard metal such as brass having a lubricating coating of wax or the like so as to permit of slippage between itself and its seats whereby when the packing nut is tightened the gaskets can be compressed without setting up twisting strains or excessive stresses in the elements of the plug.

8. A spark plug of the character described and including a metallic shell, an insulating body, an inner non-ferrous metallic gasket having a soft metal plating, and means for maintaining the body and shell assembled and compressing the inner gasket into hermetic sealing engagement with the insulating body and the shell.

9. A spark plug of the character described and including a metallic shell, an insulating body, an inner nonferrous metallic gasket having a cadmium plating, and means for maintaining the body and shell assembled and compressing the inner gasket into hermetic sealing engagement with the insulating body and the shell.

10. A spark plug of the character described and including a metallic shell, an insulating body, an inner non-ferrous metallic gasket having a tinplating, and means for maintaining the body and shell assembled and compressing the inner gasket into hermetic sealing engagement with the insulating body and the shell.

1l. A spark plug of the character described and comprising a metallic shell, an insulating body, an inner non-ferrous metallic gasket interposed between the metallic shell and the insulating body and having a soft metal surfacing capable of flowing into the pores of the insulating body when compressed between the body and the shell to eifect a hermetic seal, and means for maintaining the body and shell assembled and also acting to compress the gasket into hermetic sealing engagement with the insulating body and the shell.

12. A spark plug of the character described and comprising a metallic shell, an insulating body,

' an inner non-ferrous metallic gasket having a lead coating, and means for maintaining the bow and shell assembled and compressing the inner gasket into hermetic sealing engagement with the insulating body and the shell.

13. A spark plug of the character described and comprising a metallic shell. an insulating body, an inner copper gasket interposed between the metz-Jlicshellandtheinsulatingbodyandhaving mamar a soft metal coating capable of owing into the pores of the innilating body when compressed betweenthebodyandtheshelltoeilectanhermeticsesLandmeansformaintainingthebody and the shell assembled and also acting to compress the gasket into hermetic sealing engagement with the insulating body and the shell.

CHARLES R. BUENING.

Images