US1269860A - Spark-plug. - Google Patents

Description

H. F. SADGEBURY.

SPARK PUIG.

APPLICATION FLEU NOV. IU\ 1913.

1,269,86. Patented .1mm 18, 1918.

H. F. SADGEBURY.

SPARK PLUG.

APPLICATION min N0v.104 1913.

Izltfnted J une 18, 1915i 2 SHEETSSHEET 2.

fwmam SuM-rg, 5y y @4km/lm ATTORNEY W WW UNITED STATES PATET FFICE.

HERMAN F. SADGEBURY. 0F DAYTON. QHIO, ASSIGNOR. BY ME WOLVERINE SPARK PLUG COMPANY, INC

PORATED IN 1916.)

SPAR K-PLUG.

Continuation of application Serial No. 660,059, tiled November 13, 191i.

Serial No. 800,361.

7h uit] `whom it may concern Be it known that I, HERMAN F. SADGE- BURY, n eiti/len of the lhiitetl Stuten, resitlingr` nty 12S lurli street, in Dayton, county of lltlontgoniery, und Stute of Ohio, linie invented eert-nin new nntl useful Improve ments in Spark-llugsq ot' hielt Yl tleelttre the following to he :t full: elettr, untl exact description.

This invention reltttes to spark plugs for internal combustion engines :intl more p:tr tieularly to n wu); of securing the insulator in the cylinder whether hy seeuriunr it in tt bushing tletttehnhlyY niountetl in the ejelintler us is customary or hy omitting; the tlettn-hnl le bushing :intl infetti-ing the insnlntor ilirectzljyr in un opening in the engine eylintler. It is iletl as u continuation or substitute for my pendingr application No. titjtittlll filetl November 13, i911 disclosing ttll thut is disclosed in smid pentling application hut containing ndtlitionnl mutter hesitles.

)ne of the innin olljeets of this invention wus to provide such connection between the insulator :intl the meinher in which it is to sent and such Ineens for holtlintgT the former in the lutter its to permitI ot' verY rupitl removal of it therefrom unil without the ne- Cessity of using :t Wrench or :my tool in sut-h operations. Along with the provision of quick attnchnhilitjtY :intl tletuehuhilittY ol' the insulator it wus of course also retnetnlleretl that the Ineens tor ixing unt! holding the insulator in plut-,e would hure to be, hie-hl)` effective to hold the lutter etl'eetively in ploetiu its Sent so ns to prerent lenletge ol' ,ons from the cylinder when nncler eotnpression :intl it was :1n object of my invention to pro vit'le means accomplishing this.

The above objects :1re :tcoontplishetl with my invention by the use of n rotntuhle niember haring :t handle shnpetl tor convenient grasping' lo)V the hnnfl. so that, it muy l e munuallv turned und hnvine :t lienriug or llenr ings in some tiXctl tnenilter suer ns the hushing` in which the insulator is to sent. or if there is to lle no bushing. in n tient-ing; or beurings rig-itl with the engine easing. :Intl having t1 cani portion, or :1 portion eeeentritj; to the axis of the bearings which acts either directly, or through some intermediate con neetion, upon the insulator, when the rotte table member is merelyv rotuterl. und without being given tiny other movement Whitt-ever,

Specification of Letters Patent.

ASSIGNMENTS, TO A CORPORATION "JF NEW YRK, (INCOR- Patented June i8, 1918.

his aplllieatien. filed` metemeer 10,

in suoli n nity :as to 'loree the insulator tirnlly to its sent; null hohl it there until the rot tltehle in cnln or eccentrie portion ol tinI rotittnhle pressing on Velten the insnlntor is thus 'r'eetl 'the itetttlntor.

table member is tttlnptetl to lle withllruwn from its bearings, it neecl he, to permit eentplete. wttthelrnwnl of the tnszulntnr from its sont.4

his withdrnn'nl ol the inenlutor is nsenl :intl tlesirultle Y[or ent-h imposes :ls cleaning the instllntor.` illumine or :nljustlnl: the electrode or electrodes enrrtetl therelly,

for priming the engine` or eren another insultttor or elementJ for the suhst it ut ing: substituting another insulntor for use for some other Purpose such :is :in :tttnclnnent tor eonnecting' u pump with the engine so that the letter muy operate the formel:

The ahove principle ol' operation is npplied in n nlnnlter of dill'erent formsy of eon struction herein shown :mtl tleserilietl nntl unquestionubly other loi-ins een reutlily he devised making use. ofY in); novel priueiple ot operation.

The ntunher herein tliselosetl,

however, ure lielieretl sullieient to eompletel)Y indicate my invention unil tell hon' it muy lie ronde use of.

lense the pressnre on the insnlutor.

more the insulator entirel \Y frena its sent the rotntuhle Int-inhetis pulletl nxiullv out of its hearings nml the opening: in the insulator 'whereupon the insillutor is completely treed for n'mnnnl reinornl front its sent ln another l'orm illustrntetl l ntnlie use ot two pins or rt'ltntnltle tueinllersv hztting earn or eeeentrie portions projeetinn over shoulders on the insulutor insteznl ot hzttng :l single rotultztllle ntetnlfetextending! through the msniutor.

ln still :mother torni l use n single rotti-- tablen'ielnller but here |t extentl through n noteh in the sitle of thr ins'ttlntt tnstentl of through n hole through the insulfetor,

I have :stili further illtwtrnteti; n form in rotalalrile member does not extend n olf the insulator at all. but has bearings on the bushing and extends tenen alli.A longitudinally of the plug and at the side of the linut-alor and with the` direction of action oi the com or `eccentric portion of the rotatable member transverse lo the axis of the insulator. Yln this forni .l niake use of a wedge extending through a transverse opening in the insulator having end bearings in the bushing and abutting.: at one end against the rotatable member and adapted. when the rotatable member is rotated in its bearings. to be moved transversely of the plug and in such movement by reason of its` Wedge action on the insulaire. forcing the latter, at an angle to the direction of 1no\e ment of the Wedge firmly against. its seat in the bushing.

It will be seen that in all there forms it is immaterial sofar as my broad invention is concerned, whether the cani or eccentric portion of the rotatable member acts directly upon the insulator or through some intermediate element or elrnnents; also that it is immaterial whether the ellective action of the cam or eccentric portion of the rotav table member is in the direction of seating 'movement of the 'insulator or some other direction with suitable connections, such as the Wedge shown, for changing the direction of action of the force applied to canse it to act to move the insulator tirnxl y against its seat.

In the preferred form in which the rotatabie member extends transversely throngh the insulator I may so shape the hole in the insulator that the rotatable member cannot turn all the way over but only slightly past the positirjni at which it has imparted the grratest movement or displacement to the insulator, whereupon its cani or eccentric portier engagea the side of the opening in the insulator and prevents its further rotation in that direction.` and since the rotatable member is then slightly past its position iniparling the greatest throvv' to the insulator the latter will have to be again tightened' slam-what against its seat before the rota taliltmember can be turned back to its start ihpj position. lli'ith this construction when lll;- :faior is fully in place it more or less loi .rd there by the eccentric or cani portivo. of the rotatable member which elferivvlf( :x1-is f; arf; jarring or light taps tend-- ing .to lm n the rotatable member and ilwnngh it free the insulator. Of course this limiting of the rotative movement of the relai-.dilaineinbt-r may be arizon'iplisln-.d in other 'vnf-'s .so as lo accomplish the lockingy action w. the insnlatrn'v For example, the higiene? 'n efr-*inv casing! may be provided we desired testent, and thus lmnl', instead of the insulator, the rotation of the rotatable member.

The above locking action of the rotatable member is not necessary, however, and, in fart, l pre fer to so locate the transverse hole in the insulator that such will not result, as the friction between the cam or eccentric portion of the rotatable member and the insulator is sufficient to resist all occurring accidental are or taps which might tend to loosen the parts. But if it is desired to provide for limiting the rotation of the rota table member l may make use of some fixed stop or projection on the bushing or casing to limit this rotation. n

More specifically it was an object of this invention to have the insulator carry both electrodes and my invention embodies a novel arrangement of these electrodes and provides for electrical connection from one of them to the engine cylinder by means of the rotatable member when the latter is holding the insulator in its seat. Removal of the rotatable member therefrom breaks the electrical connections and prevents sparking at the electrodes when the rotatable member is not in place. By this construction one can quickly, by merely removing the rotatable members of his spark plugs, render his engine inoperative by others not having rotatable members fitting his spark plugs. It is not to be considered necessary to my broad invention for fixing the insulator in place, that the insulator carry both electrodes for it may, if desired, carry but one, the engine casing or spark plug bushing carrying the other in some Well known manner, and in this case the rotatable member would not serve as part of the electrical connections at all. To the end that both electrodes can be removed with the insulator for cleaning or adjustment and that their relationship will not be changed in removing the insulator, l prefer to mount both electrodes in the insulator so that they are both carried by the same element. Some of the forms have shown both electrodes as carried by the insalator and some but one and I may or may not, as desired, have the rotatable member when in place directly engage with one end of one electrode. In one forni shown a little gap in which an additional spark will jump if desired is provided.

Since in the preferred form the bearings for the rotatable member are not of the same diameter and the rotatable member must be placed in them in the saine relationship` and since in practice it is found that the bushings when screwed in the engine casinpr will not always present a single sel. of bearings in the position most convenient for insertion and removal of the rotatable member. l may if desired provide a plurality of bearings or sets pf bearings for the rota` the removable rotatable member is in direct contact with one of the electrodes when the insulator is locked in place in the bushing. In this form also the opening in the insulator is so located, that one of its sides prevent complete rotation of the rotatable member but stops it after just passing the. posi tion effecting maximum displacement of the insulator.

i In the preferred form shown in Figs. 1 and 2, the plug is composed of two main parts, the bushing l and the. insulator 2, the former having an externally threaded portion 3, by means of which it can be removabl securedin a threaded opening in the wa l of an engine cylinder. The insulator 2 is adapted to be removably secured Within the bushin 1. The insulator in this form carries bot electrodes, 4 and 5, for the spark though it may carry but the one 4, if desired, leaving the other to be carried by the bushing. By the removal of the insulator from the bushing the electrode or electrodes carried thereby are also taken out of the engine for examination, cleaning, or adjustment, without the necessity of unseren`Y` ing the bushing from the engine. The mem ber 1 is preferably of non-circular shape at its upper portion whereby it can be conveniently operated by a wrench for inscri ion in and removal from the cylinder. The bush-- in 1 is hollow and the diameter of the axial opening is larger at the upper end than at. the lower externally threaded end7 there being formed at the place where the diameter of the axial opening changes an internal shoulder 6.

The exterior of the insulator Q is shaped at its intermediate and lower portion to lit in the opening in the bushing l. It is provided with a shoulder T adapted when vthe insulator is in place in the bushin g to rest on the shoulder 6 being, in use liowever, preferably separated therefrom by a gasket 8 of asbestos, copper asbestos, soft copper or other suitable material adapted to assist in forming between the shoulders a fairly gas tight connection to rerent escape of gas under compression in t e cylinder. Instead of this type of gas tight connection between the insulator and bushing I may omit the |gasket entirely and grind very smoothly the contacting surfaces ot' the shoulders 6 and 7 which does very well in practice in forming a gas tight fit or I may employ, instead of the shouldered connections between the bushing and insulator, a conical lit between these members throughout their length or .such of their length as desired. either grinding the contactingr conical internal and external surfaces and omitting a gasket of other material between them or omitting such smoothing operation on the surfaces and fitting a suitable gasket between the conical surfaces,

As indicated above the insulator is firmly forced against its seat and held there, rev gardless of the particular form of seating connection between the insulator and bush ing. by means of a rotatable member journaled in lixcd bearings und having a portion actingr as a cam. eccentric or crank when the rotatable member is turned to engage 'the insulator and torce it lirmly against its seat in the bushing. ln thc torni illustrated in Figs. 1 and Q and now being described the portion ol the insulator above the shoulder is provided with :i diametrical opening 9 counter bored at both ends at llfl and having the intermediate straight portion l1 which is engaged by the rotatable member when the latter rotated. to force the insulator against its scat in the bushing. The

bushing is provided near its top with diametrically opposite holes 1Q and 13. one or both of which are elongated somewhat in the plane of the openings at right angles to the axis of the plug, and the vertical dimension ot the openings at right angles to the elonggation of the openings are different for the different holes. The rotatable member 11i has two concentric bearing portions 15 and 16 of different diameters and corresponding respectively with the vertical dimensions et" the holes 12 and 13 in the bushing. Between the bearing portion 15 and 16 is the cam, eccentric or crank portion i7 which, so far as its function is concerned. may be either in general concentric with the bearings 15 and 16 but having a cam portion on one side, maybe shaped olii' the center of the bearings 15 and 16 on the order of a crank, or may be inst turned around but eccent rically to the bearings 15 and 16. Still other forms of the construction might suggest themselves but the one shown is believed sniciently illustrative. In it the intermediate portion of the rotatable member bctween the concentric bearing surfaces 15 and 16 is circular but turned eccentrically to the axis of the concentric 'bearing portions 15 and 16.

All that is necessary is that this portion of the rotatable member is of such shape or contour that when the member is rotated some portion of it whose periphery does not form a circle concentric with the axis of the bearings 'i5 and 16 will swing around and by engaging the insulator, and in the preY ferreel forni the bottom of the middle por tion l] of the diamci'rical opening! in it, torce the insulalor longitudinally of the bushing to firmly seat it against its seat in the buslr ing. linnn the parte. are in place the rotalalllv member extends through the transverse opening in lhe insulator and has its bearings 15 and lil resting resiiectively in the holes 1Q and l?? in the bushing. In this position thc com. eccentric, or crank portion 17 of the rotatable member l-'i is Within the opening 9 of the insulatorand when the parts are tight the rotatable, member is in such angular relationship thaty the part of portion 17 projet-,tingr farthest, t'roin the axis of the bearing 1:3 and lt is against the lower surface 1l otl the openingr J and is holding the insulator lir1nl against its seat, Rota tion of the rotatable member causes the eo Centric or ram portion 1T ot` it to move upwardly and release its pressure on the insulator. 'heu the parts are thus loosened the rotatable member Inav be axiallyr withdrawn from the holes l2 and 13 and the opening: 9 of the insulator after whieh the latter can be uori'nallyv withdrawn troni the bushing. The. rotation ol tht-'member by the opera tion ot' the handle brings the ram, errentrio or eranlt portion in rontaet with the insuA lator or electrode means a-t a point that is in sulistantiel alinenient over the bearingr axis ofthe member` as well as with the point, ol 'ontaet ot' the member against thiI bushing;

.so `that these points item2' `itllattll Pause a substantially "dead renter` eli'er't of the partsl involved. 'the result is. there is little or no tendeney to rause the member to be turned backward or forward b v the reaeting forces created when the member is rotated and the rain portion is brought into eontaet with the insulator. .\t least. no uionient of torre ot' sutlieient eii'ei-t to exi-eed the trietional resistanee created b v the reaeting forces. This is mainly due to the tart that; the movement tending to rotate the cam either wa),y by the reacting torres is exerted Sol eilose to the axis of the rotatable member as to be actingr practically on the line of the axis, and therefore produeesl a moment ol forte insutlieient to overcome the t'rietiooal resistanee of the member against rotatirui` Should the insulator he stuck somewhat in its` seat. turning of the rotatable member hrough substantiall)Y 18() will. similarly, htough action of the portion 17 upon the upper surface of the portion 11 ot the opening 9, positively force the insulator up Wardly to loosen it. After this loosening operation the rotatable member is axially withdrawn and the insulator can be freely removed. The rotatable member in the forni illustrated in Figs. 1 and Q is provided with a bent portion 18 forming a handle through whieh it can be conveniently manually rotated, inserted and withdrawn.

The insulator of my plugr may be of an)1 suitable substance sueh as poimelain or mica but I prefer to use a form of lava or other stone. It is provided with a Contact screw 19 at its upper end adapted to be eleetrieally connected with one pole of a battery. the serew there extends longitudinally through the insulator a conducting wire which projects centrally out through a conical recess in the lower end of the insulator` the wire not going straight through from one end of the insulator to the other but being bent around the opening 9 so as to leave sullieient insulation between itA and the openingr t) as well as between it and the exterior of the insulator. lVhile, as stated above, it is not necessary to have the insulator carry both electrodes I prefer to have it do so and, in the torni beingr deseribed and illustrated in Figs. l and L. another electrode 5 extends longitudinally ol' the insulator from about the renter ot the opening 9 to the lower end of the insulator from which it. projects near the periphery. 'lhe projecting portion of this elet-trede is bent laterally at 22 beneath the end of the electrode -i and between these portions of the two electrodes in proximity to each other the spark is adapted to pass. The upper end ot' the electrode 5 makes eleelrieal eonnertion with the portion 1i' of the rotatable member` which is made of metal, when the latter is holdingr the insulator in plare .ind through this rotatable member the eleetrode elefftrittalhv eonnerfts with the enveine ei linder from whieh the rirt'uit is eontinned inthe usual wav back to theother pole oi' the battery. jects. the rotatable member may or may not, as desired, directly Contact with the elect rode 5 toi it may. he just close enough to the eleetrode so that a` spark will also leap aeross the gap between these elements. if such is desired7 as is sometimes the ease. In either ease axial removal of the rotatable member serres to etlif'tivel)v break the elet'trieal oirenit for the sifiarl; whieh will not occur until the rotatable member is again properl)7 inserted in place.

As shown in Vig. i: the bearings 12 and 13 for the rotatablemember it are elongated to permit a little angular or bodily displafiment of the rotatable member to take eartot' variations in location in a transverse plane of the opening 9 of the insulator whieh inav oeeur in practice. Either or both ot them may be so elongated or, by aeeurately locating the hole in the insulator and those in the bushing, this elongation of the holes 1Q and 13 may be omitted entirely though l prefer in practice to elongate at least one of these a little.

ln the forni of the invention shown in Fig. 5 the shape of the opening in the insulator is changed as is also the horizontal holes in the bushing as instead of the rotatable member passing throuafh them a Wedge 23 iasses through these holes and opening, which wedge has an inclined portion 24 engaging the similarly inclined portion Q5 of the intermediate lower portion Y26 of the transverse opening 27 of the insulator. The ends of the wedge have straight, bearing portions 28 and 29 of ditt'erentl size adapted to work in eorrespondinglv shaped holes in the bushing. The wedge ot' this forni is adapted to be moved transversely through the As indicated above in the obinsulator by means of the same kind of a rotatable member 14 as in the referred embodiment but mounted vertically in bearings 30 projecting from the side of the bushing. The dilference in construction of this form over a preferred form described above is that the rotatable member instead of extending transversely through the insulator and acting directly upon it to force it against its seat, has its effective action transverse to the axis of the plug, and acts through the Wedge to force the insulator at right angles a ainst its seat in the bushing. To remove t e insulator of this form from the bushing the rotatable member must first. be loosened and moved vertically cndwise from its bearings and then the wedge extending through the opening in the insulator is with drawn whereupon the latter is free to be removed. The reverse of this operation takes place in assembling the parts.

Fig. 6 may be described as showing a modification in which the bushinglis omitted entirely as a part of the plug. n this the insulator seats directly in an opening in the engine cylinder in the same way the insulator of Figs. 1 and 2 seats in the bushing 1 Ears 31 projecting from the cylinder have bearin hooks against the lower sur faces of which the rotatable member seats at its bearing surfaces 15 and 16 as its portion 17 is forcing the insulator in place or holding it there. 'I he action of the parts is otherwise the same as in the form of Figs. 1 and 2.

In Fig. 7 another modification is shown in which the insulator 2 is cut away at dia mctrically opposite portions at 34 to form shoulders 35. and, instead of a single rota table member being used, passing through the insulator as in Figs. 1 and 2 two short rotatable members 36 are employed each Working in its single individual bearing in the bushing and having a portion 37 adapted to engage its shoulder 35 of the insulator and the two together act-ing to 'force the latter against its seat in the bushing. In this forni but one electrode is shown as carried by the insulator though obviously this form is also susceptible o having the insulator carry both electrodes as by running one end of one to one of the shoulders 35 for engagement with its rotatable member 36 when the latter is tightened down in place. In this form, to remove the insulator, both rotatable members are rotated to loosen them and then are axially withdrawn. whereupon the insulator may be axially removed.

In connection with this form carrying but one electrode I have shown an adjustable element 38 screw threaded at 39 'o detachably cooperate with internal screw threads 40 on the lower end of the bushing. In this way the distance of this clement 38 from the electrode 41. carried by the insulator can be varied. The upper sido ci. the element 38 ifi chambered at 42 and between the element and the lower end oi the electrode a combustion chamber including` the chamber 42, is formed. Downwardly extending and diver-ging openings 43 start adjacent the electrode 4l and extend through the element 38, and these openings serve to spread the ignited and iaming gases in the combustion chamber as they rush out through them after being ignited. The ignition in the-combustion chamber is caused by sparks passing from the electrode 41, to the adjacent points` on the upper surface of the element 38 which is of metal and being electrically connected with the bushin serves as the other electrode with a plurality of contact points around the end of electrode 41. B means of the rushing oi' ignited gases in al directions from the wmlulstion chamber through 'ine small openings 43 in the element 38 the ignited and burning gases are distributed more or less through the cylinder and a more complete ignition and combustion of all the fuel in the cylinder results. The spark gap can be varied by merely adjusting the element 38 vertically in the lower end of the bushing. Of course this feature of the invention can be used even though the insulator carries both electrodes, and can be applied to my preferred form by merely extending the lower end of the bushing Shown in Figs. l and 2, and internally screw threading this lower end a l screwing the element 38 therein. In this form the ele- 100 ment 38 would not need to form an electrode but `would serve to forni the combustion chamber and to defiect the iifnited gases they rush therefrom into the cylinder after having been ignited by the spark pass- 105 ingbctween the electrodes shown in Figs. 1 and which in such case would occur withir the combustion chamber.

ihc form shown in Fig. 8 is similar to that just described except that a single ro- 3 i retable member is employed which instead of passing through a diametrical opening in the insulator passes through a notch cut in the side of the insulator2 and serving the same purpose as the opening 9 of Figs. 1 11.5 and 2.

Relative to the embodiment of my invention shown in Figs. 10 to l5 the operation is more or less the same as in the other figures. A type of screw thread or the bushing is 12o shown which is dilerent from that which is shown in connection with the other ligures, though this does not affect my invention at all as also does not the different construction or' 'dul end of the rotatable member 125 which instead of a bent handle of the other forms, consists of a knurlcd head 44. In the forni shown in Figs. 10 to 14 I propose to force and hold the insulator in place not by direct engagement of the portion. 1T of 130 the rotatable member with the bottom of the transverse opening 9 in the insulator but through the medium of a ring 45 surrounding the insulator and located between it and the bushing and restin upon and acting against the upwardly acing shoulder 46 on the periphery of the insulator. The ring 45 has oppositely disposed openings 47 through which the rotatable member passes as well as passing through the transverse opening 9 in the insulator and the extremities of the portion 17 of the rotatable mem ber are located in these o enings 47 when the parts are in place and) serve when the rotatable member is rotated to force down the ring 45, and by reason of its seating on the shoulder 46 of the insulator, force the donwardly facing shoulder 48 of the insulator downward against its seat or shouh der in the bushing or against a gasket on the. seat in case a gasket used. In this form I have shown the openings in the ring of such shape and location as to have a corresponding side of each opening nearer the axis of rotation of the rotatable member than the other sides so that the portion 17 of the latter member will be carried against such sides of the openings in the ring after just passing the position at which it displaces the ring and insulator downwardly the maximum distance, which sides of the openings in the ring will thus serve to prevent further rotation in that direction of the rotatable member. Also when the rotatable member is thus stopped from further rotation it cannot return to release the insulator without sufficient force being applied to rotate it back past its position calling for maximum displacement of the insulator. By this construction the rota table member when rotated until it is stopped by the sides of the openings 47 in the ring acts more or less as a lock against unseating of thel insulator by any accidental jar or tap.

A similar action is presented in the form shown in Fig. 15 which in this respect dit fers only from the form of Figs. 10, 11, and 12 in that the ring 45 of the last mentioned form is done away with and the openin in the insulator shaped and located just ike the openings in the ring thus presenting a construction in which the locking and seating operation of the insulator is the same except that the portion 17 of the rotatable member coacts directly with the bottom and 4side of the opening in the insulator and 'not through the intermediate ring. Of

course in this form, I do not need the upwardly facing shoulders on the insulator Within the bushing and the insulator is shown as completely filling the bushing at this point. In the illustration in Fig. 15 I also show the upper end of one electrode in direct contact with the rotatable member instead of slightly separated therefrom as in Fig. 11 to form a sparking gap at the juncture.

The above description I believe, sulliciently illustrates my invention so that one skilled in the art can readily make and use it. I wish ily lo be distinctly understood however that the various forms are merely illustrative. I now [mrceivc Various other forms in which it may be embodied but which it seems needless to describe herein. As concerns my novel way of forcing the insulator of a spark plug to its seat and holding it there it is immaterial whether the iusulator carries both electrodes or not or whether, if carrying both, the second one makes electrical connection with a engine for return to the battery or magneto, through the rotatable number or not. l have shown and now prctcr such construction it being a very convenient arrangement and one in which. the usefulness ot the plug may be temporarily and quickly destroyed so that the en'gine cannot be run. by merely remoi ing the rotatable member from its place. This provides means whereby the owner of an engine can, by merely removing the ro tatable member, readily prevent removing of his engine by someone not intended to run it and having no rotatable member of such size and shape as to tit his plug. This feature of the invention I howex'er also desire protection for and accordingly present claims directed to it. I also consider it to be immaterial so far as my novel Vay of fastening the insulator in place is broadly concerned, whether the rotatable member acts directly on the insulator or through an intermediate element such as the ring shown in Fig. 11 or the wedge shown in Fig. i; whether the rotatable member extends transversly of the plug as in most of the tigures or longitudinally as is illustrated in Fig. 5; whether there is a single rotatable member as in most of the figures or a plurality ot' them as in Fig. 7; whether the rotatable member extends through the insulator or just over it as in Fig. 7; or whether as in Fig. 5 another element passes through the insulator; or, if some element is to 'pass through the insu-A lator. whether it is through a notch in the side of the lat-ter or through a transverse opening in it; whether the rotatable member is to be prevented from complete rotation when in place and is rotatable in but one direction to seat the insulator` to its seat as is the case with the forms of Figs. 10 to 15, or Whether the rotatable member can be rotated in either direction. to maximum displacement ot the insulator, and in either direction to release the insulator as in the forms shown in Figs. l to i): or if complete rotation ot 'the rotatable member is prevented whether this is done in the manners shown in Figs. l() to 15 or in sonic other some stop on the bushing for roi'ipcrating with some part of the rotatable member. In fact the rotatable member need not be of the shape as shown but all that is necessary is that it be so constructed so that at somo portion or portions along its axis of rotation its periphery is not a complete circle concentric with its axis of rotation so that such portion or portions will w hen the member is rotated cooperate either by direct engagement or through some intermediate element or means, so as to move the insulator to its seat and hold it there so long as the rotatable member is not turned to relea se it. l have shown the member as having between its concentric bearing portions a portion circular but turned eccentric t0 the axis of the bearing portion or portions but plainly the member might be a substantially sii-aight member of circular cross section but with a peripheral projection or cam at the lesireil point, or the same result would be awomplished h r a. member of circular cross Iser-lion with `some point or portion bent out or' alinement with the portion to form its bearing. lt is also not even necessary to the use of my broad invention that a bushing be used as m some eases, aswith engines specially made. l desire to eliminate the usual bushing adapted to detachably engage within an opening in the engine cylinder and journal my rotatable memberdirectly in bearings on i Fig. t3, the insulator seating in such case similarly to the Way it seats in the bushing in my other forms. It is only necessary that the rotatable member be revented by some tixell member at its bearings from moving in a direi-tion reverse to that in which the eccentric portion of the member acts when forcingA the insulator to its seat. The throw of the eccentric portion of the rotatable member l may vary as desired and it is not even necessary that the rotatable ymember displace the insulator the maximum amount in order for the friction between the parts to hold them in their moved position. 1t has been found in practice that the rotatable member can be stopped in positions causing a varying displacement of the insulator yet the friction without the locking effect described with reference toiFigs. 10 to 15 will be snlicient to retain the rotatable member and the insulator in their moved position suliiciently well for all practical purposes. 'lhis providest by varying the extent of rota'tion of the rotatable member, for varying the prcssue with which the insulator is held in place as desired or by more or less rotation of the rotatable member obtaining the .pressure desired in spite of slight' variations of the parts in manufacture. In fact by caretally selecting the desired resiliency for the rotatable member a pressure for the insulator on its seat is provided for which is subway such as by the engine casing as shown inl effective.

stantially constant for all conditions and which cannot be exceeded no matter how much force is applied to the rotatable member in rotating it. This feature l propose to use in manufacture and is of value in preventing so much ressure being applied as to injure the ga et and affect its durability or efliciency. In many forms of plugs this often occurs when the insulators are fastened in place by means of a' wrench and where it is easy to apply more than the necessary ower. My rotatable member is designe or manipulation wholly by the fingers and without a wrench and by varying the throw of the eccentric portion and its periphery or the distance from the axis of the rotatable member at which the fingers act, or both, it is easy to provide so that too much force will not be applied. The provision of counter boring the ends of the transverse opening in the insulator is just as `useful in connection with any of the forms Where an opening extends through the insulator', though not `hewn in connection with Figs. l0 to 15. Such is also the provision for clongatin the holes forming bearin. sin the bushin or the rotatable member.

consider it quite an advanta e in my invention to be able, by merely su ciently rotatin the rotatable member when turning it to re ease the pressure on the insulator, in the forms shown in Figs. 1 to 4, and 8 to 15, to positivel carry the insulator away from its seat. T is I consider quite an advantage because in some forms of plugs it often occurs that the insulator becomes more or less stuck in its seat or bushing so as to require some little eort to loosen it even when the member which holds it in place is no longer lt is obvious that in my invention embodied in the preferred form, merely rotating the rotatable member so as to carry its eccentric portion into cooperation with the upper side of the transverse opening 9 in the insulator will serve to force the insulator up instead of down and positively unseat the insulator should it be stuck in its seat. To apply this to the form shown in Fig. 6, in which the useful bushing is eliminated, the bearings for the rotatable member would, of course, have to be formed to coperate not only with the upper portion of the rotatable member as shown hat also would extend beneath the bearing portions of such rotatable member.

With rnv improved way of forcing and holding a sparkplug insulator in place the latter can be conveniently and readily removed without the use of a. wrench and equally as conveniently restored to its place in the cylinder. ln putting the insulator of my preferred form of Figs. 1 and 2 in place it is first placed bv hand to its seat so as to aline its transverse opening with the bearirgs for the rotatable member. The rotatable member is then inserted into its bearin s and through the opening' in the insulator. `urn- Jng of the handle. le of Figs. 1 and 2 so as Vto stand upright then rotates the rotatable member to cause its portion 17 to force the insulator firmly against its seat, and riction of the parts is sutlieient to hold the parts in this position for al] practical puroses until it 1s desired to remove the insuliitors. 'hen such is desired all that is neeessarv is to rotate the rotatable member until it sufficiently frees the insulator' when it can be axially removed. Then removed the insulator is free for longitudinal removal from its seat. It the insulator is stuck in place turningr of the handle 18 vertically downward when the rotatable member is in place will positively move the insulator upwardly from its seat and eliminate the sticking so that upon removal of the rotatable member the insulator may be readily withdrawn.

The terms calm eocentrie, "*crankj lever where used in ther claims individually are to be interln'eted in generic sense to cover all the terms, where such interpretation is consistent with the novel operation of this device and the other phraseology of the claims.

Having described my invention and various embodiments of it what l claim as my invention isi# l. In a spark plug for internal combustion engines, the combination of lixed member having an opening,l a bearingr fixed relative to said member; an insulator adapted to seat in said opening and carrying an electrode; and a rotatable member adapted to rotate within said bearing and having a eam portion adapted when the rotatable member is rotated to force the insulator against its seat in the opening.

2. ln a spark plug?r for internal combustion engines, the eombimition of aY fixed member having an opening; an insulator carrying un electrode adapted to seatin said opening; bearings fixed relative to said fixed member; and rotative means mounted to 1otate in said bearings and having a cam portion adapted to force the insulator to its seat when the rotatable means is rotated.

3. In a spark plug t'or internal combustion engines. the combination of a fixed member having an opening; an insulator carrying an eleetrode adapted to seatk in said opening; bearings xed relative to said fixed member; and rotative means mounted in Said bearings and having a cam portion adapted to torre the insulator to its seat when the rotatable means is rotated in one direction and to move the insulator from its seat by movement in the other direction.

4. In a spark plug l'or internal combustion engines. the combination of a bushing adapted to be removably secured in an engine Cylinder and having a bearing fixed relative thereto; an insulator adapted to be removably secured in 'said bushing and carrying an electrode; and a rotatable member adapted to be removably jonrnaled in said bearing and having a ram portion adapted to coat-t with the insulator when the rota table member is rotated to move the insulator relative to the bushing.

:3. ln a spark plugnlr for internal Combustion engines, the combination of a bushing adapted to be removably secured in an enL gine cylinder and havintt a bearing fixed relative thereto; an insulator adapted to be removably secured in said bushing and car-- rying an electrode; and a rotatable member adapted to be removably journaled in said bearing and having?r a -am portion adapted to conet with the insulator when the rotatable member is rotated to move the insulator in either direction relatively to the bushing.

t3. ln a spark plugl t'or internal combustion engines` the combination of a bushing adapted to be removably secured in an engine vlinder and having :i bearing tixed relative thereto; an insulator adapted to be removably secured in said bushing and carrying an electrode; and a rotatable member adapted io be removably journaled in said bearing and having a eam portion adapted to eoact with the insulator when the rotatable member -rotated to move the insulator against its seat in the bushing.

i'. In a spari( plug i'or internal combustion engines, the combination ot' a bushing adapted to be removably secured in an engine cylinder and having a bearing fixed relative thereto; an insulator adapted to be removably secured in said bushing, and earrying an electrode; and a rotatable member adapted to be removablyy journaled in said bearing and having a cam portion adapted to eoact with the insulator when the rotatable member is rotated to move the instr` lator to its seat in the bushinfY :ind hold it there until the rotatable member is turned to release it.

8. In a spark plugr for internal combustion engines, this` combination of a bushing having diametrieally opposite concentric bearing,r openings; an insulator having a transverse opening therethrough carrying an electrode and adapted to seat in the bushing; and a rotatable member having concentric bearing portions for location in thev bearing openings in the bushingr and an intermediate portion for working in the transverse opening in the insulator, the periphery of such intermediate portion extending tarther from the axis of the concentric bearintgr portions at some points than at others so as to. when the rotatable member is rotated in its bearings, engage the inside of the opening in the insulator andvmove the latter relatively Q0 lhe bushing.

9. In a spark plug for internal combustion engines, the combination ot' a bushing having diametrically opposite concentric beari g openings; an insulator having a transverse opening therethrough carrying an electrode and adapted to seat in the bush,- ing; and a rotatable member having concentric bearing portions for location in the bearin openings in the bushing and an intermetiate portion for working in the transverse opening in the insulator, the periphery of such intermediate portion extending farther from the axis of the concentric bearing portions at some points than atrothers so as to, when the rotatable member is rotated in its bearings, engage the inside of the opening in the insulator and move the latter relatively in either direction to the bushing.

10. 1n a spark plug for internal combusy tion engines, the combination of a bushing having dianietrically opposite concentric bearing openings; an insulator having a transverse opening therethrough carrying an electrode and adapted to seat in the bushing; and a rotatable member having concentric bearing portions for location in the bearing openings in the bushing and an intermediate portion for working in the transverse opening in the insulator, the periphery of such intermediate portion extending farther from the axis of the concentric bearing portions at some points than at others so as to, when the rotatable member is rotated in its bearings, engage the insideY of the opening in the insulator and move the latter relatively to the bushing against its seat in the latter.

ll. In a spark plug for internal combustion engines, the combination of a bushing having diametrically opposite concentric bearing openings; an insulator having a transverse opening therethrough carrying an electrode and adapted to seat in the bushing; and a? rotatable member having concentric bearing portions` for location in the bearing openings in the bushing and an intermediate portion for working in the transverse opening in the insulator, the periphery of such intermediate portion extending t'arther from the axis of the concentric bearing portions at some points than at others so as to, when the rotatable member is rotated in its bearings, engage the inside of thc opening in the insulator and move the latter relatively to the bushing against its seat in the latter and hold it there until the rotatable member is turned to release it.

v l2. In a Aspark plug for internal combustion engines the combination of a hollow bushing having an internal shoulder; an insulator having an external shoulder adapted to rest on the internal shoulder;'a plurality .of diametrically opposite holes in the bushing; a transverse hole in the insulator;

and a rotatable member mounted in the holes in the bushing and insulator and having a cam portion within the opening in the insulator for forcing the shoulder in the insulator irmly against the shoulder in the bushing when thc rotatable mcmbcr is rotated the cam portion ot' the rotatable member serving when its cam portion is rotated beyond a position calling for maximum displacement ot' the insulator to lock thc insulator lirmlyl in place and to lock itself against turning to release thc insulator.

13. In a spark plug for internat combustion engines, thc combination of a bushing adapted to be removably secured inan engine cylinder: an insulator adapted to rest therein and carrying a plurality oi' electrodes; a contact screw electrically connected with one ot the electrodes; a transverse hole in the insulator; diametrically opposite holes in the bushing; and a rotatable member mounted in the transverse hole in the insulator and the openings in the bushing adapted to removably secure the insulator and 'bushings together.

1-1. ln a spark plug for internal combustion enfrines, the combination of a bushing adapted to be removably secured in an'engine cylinder; an insulator adapted to rest therein and carrying a plurality of electrodes; a contact screw electrically connected with one ot the electrodes; a transverse hole in the insulator,- diamctrically opposite holes in the bushing; ind a rotatable cam bearing member mounted in the transverse hole in the insulator and the openings in the bushing adapted to removably secure the insulator and bushings together.

15. In a spark plu for internal combustion engines, the com'iination of a bushing; an insulator adapted to seat therein and carrying an electrode; and a single rotatable member rotatable about an axis at an angle to the axis ot the plug for the purpose of locking the insulator in the bushing.

1G. ln a spark plu for internal combustion engines, the com'ination of a bushing; an insulator adapted to seat therein a transverse opening through the insulator; a member located in the opening and coat-,ting with the bushing to hold the insulator in place; and an electrode electrically connected with the tx-'ansverse member in the insulator and therethrough with the bushing.

17. In a spark plug for internal Combustion engines, the combination of a bushing; a removable insulator therefor and carrying an electrode; a rotatable member having a cam portion for forcing the insulator against its seat in the bushing; and means for preventing further movement of the rotatable member after the cam has reached :its position effecting sufficient displacement of the insulator relative to its bushing.

18. In a spark plug for internal combustion engines, the combination of a bushing; an insulator adapted to seat therein and carrying an electrode; and a rotatable member having a cam portion for forcing the insulator m place in the lushing when the rotatable member is rotated the insulator adapted t0 prevent further rotation of the cam after it has reached its position displacing the insulator the most in the direc tion of its seat.

19. In a spark plug for internal combustion engines, the combination of a member; a removable insulating element carrying an electrode; and a rotatable member having a portion of its exterior eccentric to its axis ot rotation such )ortion serving when the member is rotated to attach the insulating element to the first mentioned member.

20. In a spark plug for internal combustion engines, the combination of a bushing; a removable insulator adapted to be attached thereto carrying an electrode; and a member removably journaled for rotation in the bushing and having a cam portion serving when the melnber is rotated to move the insulator transversely to the axis of the rotatable membenand attach it to the bushing.

21. An insulator for spark plugs haviner a transverse opening extending therethrough adapted to receive a securing` member for the insulator; an electrode extending from the opening to one end of the insulator forming one spark terminal; and a/second electrode extending longitudinally through the insulator and forming another spark terminal.

22. AnA insulator for spark plugs having a transverse opening` extending therethrough adapted to receive a. securing member for the insulator, counter bored at its ends. an electrode extending from the opening to one end oi' the insulator foi'ining one spark terminal; and a second electrode extending longiturlinally through the insulator and vforming another spark terminal.

In a spark plug for internal combustion engines. the combination of a. hollow bushing having diainctrically opposite bearing openings therein: an electrode carrying insulator adapted to seat in said hollow bushing and having a transverse opening therethrough counter bored at its ends; and a rotatable member passing through the insulator opening and journaled in the bearing openings in the bushing and haring a pori ion intermediate its bearings where its periphery is at greater distances from the axis ot' rotation ot the member at some places than at others adapted when swung around upon rotation of the rotatable ineinbcr to engage tlubottom of the opening in the. insulator intermediate the counter bored portions and `force the insulator bagainst its @eatin the bushing.

'24. Ina spark plug for internal combustion engines, the combination of a bushing; an insulator having a transverse opening carrying an electrode and adapted to scat in the bushing; a rotatable member extending through the opening in the insulator and having cam portion for forcingr the insulatoi in place in the bushing when the rotatable member is rotated; and bearing openings in the bushing for the ends ot' the rotatable member one of these heilig elongated in a direction concentric to the axis of fthe plug,

25. In a spark plug for internal combustion engines, the combination of a hollow bushing; an insulator adapted to seat therein and carrying an electrode; an electrode forminor element attached to the lower end of the bus ling and forming a chamber between it and the lower end of the insulator within which is the electrode carried by the insulator; and diverging openings in the electrode forming element for spreading the ignited gases when rushing therethrough after being i nited by sparks passing between the electrodges, the wallsl of said diverging openings provided with a plurality of points around the entrance to the openings between which and the electrode on the insulator a series of sparks occur.

2G. In a spark plug for internal combustion engines, the combination of a hollow bushing; an insulator adapted to seat therein and carrying an electrode; an electrode forming element adj ustably attached to the lower end of the bushing ind forming a chamber between it and the lower end of the insulator within which is the electrode carried by the insulator: and diverging openings in the electrode forming element for spreading the ignited gases when rush ing therethrough after being ignited by sparks passing between the electrodes, the walls of said diverging openings provided with a plurality `of points iround the entrance to the openings between which and the electrode on the insulator a series of sparks occur.

2T. In an article of the class described..

the combination with an insulator carrying an electrode. of a bushing containing a seat for the insulator and having a pluralityl of diametrically disposed bearing openings` and cam bearing l means rotatable in the bearing openings to engage the insulator and force it against its seat in the bushing.

28. A spark plug comprising a bushing having openings at right angles to the axis of the bushing, an insulator carrying an electrode having an opening coperating with the holesin'the bushing, a rotatable member to. be inserted through the openings in the bushing and insulator and having the portions engaging the bushing concentric to one axis and the portion engaging the insulator concentric to a different axis.

29. A spark plug comprising an electrode carrying insulator, a bushing having an opening to receive the insulator' and bearings fixed with reference thereto, and a rotatable member adapted to cooperate with said bearings and having a portion of its periphery projecting to engage the insulator whereby when t-he member is rotated the insulator will be moved axially in one direction or the other depending upon the direc tion in which the member is rotated.

30. In a spark plug, the combination of a bushing, electrode carrying insulating means adapted to seat therein, and a single rotatable member rotatable about an axis extending at a large angle to the longitudinall axis of the bushing for the purpose of forcing the means firmly against its seat in the bushing and automaticallyT holding it there.

31. A spark plug comprising an electrode carrying insulator, a bushing adapted to receive the same, and a member rotatably engaging in the bushing and i sulator to ro tate about an axis at an ang e to the longitudinal axis of the insulator adapted to press in opposite directions on the insulator and bushing when rotated, to force and hold the insulator against the seat in the bushing,

32. A spark plug comprising in combination, a bushing, an electrode carrying insulator removably mounted in the bushing, and a crank-like member rotatably' engaging in the bushing and insulator and serving when rotated to force the insulator' firmly against its seat in the bushing and to hold it ythere by reason of the crank-like member assuming a substantially dead eenw ter relationship between the insulator and bushing.

33. In a spark plug, the combmation of a bushing member, an insulator member adapted to seat therein, and a rotatable member rotatable about an axis at an angle to the axis of the other members and ful'- cruming'against one of the first mentioned members and acting against the other in lsubstantially alinng but oppositely directed lines of 'action passing through points close to the fulcrum point whereby the moment of force tending to rotate the rotatable member through the reaction of the first said members will be too small to overcome the rictional resistance against the rotatable member.

A 34. In a spark plug, the combination of a bushing, an electrode carrying insulator adapted to seat in connection therewith, and 'a rotatable member rotatably engaging the insulator and bushing about an axis at an' angle to the longitudinal axis of the insulator, saidaxis being on a' line that will pass through the projected transverse area of the insulator, said' member serving to force the insulator to its seat.

35. In a spark plug, the combination of a fixed member having an openime;` a bearing fixed relative to said member, an electrode carrying insulator adapted to seat in the member, and a rotatable member adapted to rotate against said bearing and having a portion adapted to act against the insulator when the member is rotated to press the in- 'sulator against the seat in the fixed member, said rotatable member' having means whereby it may be operated.

36. In a spark plug, the combination of a fixed member having an opening, a bearing fixed relative to said member, an electrode carrying insulator adapted to seat in' the member, and a rotatable ymember adapted to rotate against said bearing and having a, portion adapted to act against the insulator when the member is rotated to press the insulator against the seat in the fixed member, said rotatable member being so arranged through the insulator and fixed member as to require complete removal from both the same to permit them to be separated from each other.

37. In. a spark plug, the combination of a bushing 1nember,. a separable member including an insulator, adapted to seat therein, and a rotatable member rotatable about an axis at an angle to the axis of the other members and fulcruming against one of. the first mentioned members, and acting against the other in substantially alining but oppositely directed lines of action passing through points close to the fulcrum point, whereby the moment of force tending to rotate the rotatable member through the reaction of the first said members Will be too small to overcome the frictional resistance against the rotatable member.

38. In a spark plug, the combination of a relatively fixed member; an electrode earrying insulator adapted to seat therein; and a single pressure applying element rotatable about an axis at a` large angle to the axis of the insulator to lock the insulator to its seat.

39. An insulator for spark plugs having a portion adapted to be engaged by a securing member for the insulator, an electrode extending from said portion to one end of the insulator forming' a spark terminal, and a second electrode extending longitudinally through the insulator and forming another spark terminal.

40. In a spark plug, the combination of a relatively fixed member; an electrode carrying insulator adapted to removably seat therein; and an element. removable, by movement in a plane transverse to the axis of the insulator, and adapted to be so actuated as to apply pressure to the insulator i'n the direction of its axis to lock the insulator toits seat.

41. In a spark plug, the combination of a relatively fixed member; an electrode earrying insulator adapted to removably seat therein; and an element, provided with an operating handle by which said element may be removed by movement in a plane transverse to the axis of the insulator and by which said element may be actuated so as to apply pressure to the insulator in the direction of its axis to lock the insulator to its seat.

'42. In a spark plu the combination of a relatively fixed mem er; an electrode carrying insulator adapted to removably seat therein; and an element, removable by movement in a plane transverse tothe axis of the insulator and extending over a portion of the insulator, said element being adapted to be so aetuated as to apply pressure to the insulator in the direction of its axis 'to lock the insulator to its seat.

43. In a spark plug, for internal combus tion engines, the combination of a ixed member having a seat and an Opening, an electrode carrying insulator adapted to pass into the opening and against the seat and a single manipulatively operable yielding pressure applying element for forcing the insulator against its seat in the fixed member and holding it there in opposition to pressure exerted from the engine chamber when the plug is in use in the same.

44. A spark plug comprising a fixed member having an opening and a seat for an insulator, an electrode carrying insulator adapted to pass into the opening and against the seat and a fastening member disposed transversely in the insulator and means whereby the fastening member may be manually operated to exert yielding pressure on the insulator to force the same firmly against its. seat in the fixed member.

45. In a spark plug, the combination of a bushing, an electrode carrying insulator adapted to seat therein and rotatable, yielding, pressure applying means adapted to rotate about an axis at an angle to the longitudinal axis of the insulator in coperation with the insulator and bushing to force the insulator against its seat in the bush- 1ng.

46. In a spark plug, the combination of a bushing, an electrode carrying insulator adapted to seat therein and a rotatable, somewhat yielding, fastening member forcing the insulator against the seat in the bushing when the fastening member is rotated when in cooperation with the insulator and bushing.

47. In a spark plug, the combination of a bushing, an electrode carrying insulator adapted to seat in connection therewith and a rotatable resilient member rotatably eo operating with the insulator and bush'mg about an axis at an angle te the longitudinal axis of the insulator, said axis being on a line that will pass through the projected transverse area of the'insulator, said resilient member serving, when rotated, to force the insulator against its seat.

48. In a spark plug, a bushing, an electrode carrying insulator adapted, to seat in the bushing and a crank like resilient member rotatably engaging with the bushing and insulator and serving, when rotated, to force the insulator against its seat -in the bushing and to hold it there by reason of the crank like member assuming a substantially dead center relationship between the insulator and bushing.

49. In a spark plug, a bushing member, an insulator member carrying an electrode and adapted to seat therein and a resilient member rotatable about an axis at an angle to the axis of the other members and acting against the other in substantiall alined but eppositely directed lines of ae ion passing through points close to the fulerum point whereby the moment of force tending to rotate the rotatable member through the re action of the irst said member vvvill be too small to overcome the frietional resistance against the resilient rotatable member.

50. In a spark plug, a bushing, an eleotrode carrying insulator adapted to seat therein and a cam like yielding fastening member adapted to be rotated to apply a gradually increasing yielding pressure of 'the insulator against its seat in the bushmg.

5l. In a spark plug, a bushing, an electrode carrying insulator adapted to seat therein having yielding fastening means for holding the insulator against its seat in the bushing, said yielding means directly engaging the insulator and bushing and Inanually manipulative to apply a. yielding pressure on the same.

52. In a spark plug, the combination of a relatively fixed member, an electrode carrying insulator of relatively frangible material adapted to removably seat therein and a single yielding pressure applying element acting directly upon the insulator and rotatable to apply a yielding pressure to lock it to its seat.

In testimony whereof I afix my signature in the presence of two Witnesses.

HERMAN F. SADGEBURY. lVitnesses Cnes'rnn H. BnAsnL'roN, R. J. HAYNES.

Images