US2375822A - Spark plug construction - Google Patents

Description

May 15, 1945. J. J. ROSE SPARK PLUG CONSTRUCTION Filed Sept. 18, 1943 S JIII EE 3/1 H/IV/III-E FIG.4-

INVENTOR Q/OHN R0 SE 6,12 A TTORNE YS Patented May 15, 1945 2,375,822

UNITED STATES PATENT OFFICE SPARK PLUG CONSTRUCTION John J. Rose, Dayton, Ohio Application September 18, 1943, Serial No. 502,888 8 4 Claims. (01.123-169) (Granted under the act of March 3, 1883, as

amended April 30, 1928; 370 O. G. 757) The invention described herein may be manufactured and used by or for the Government for governmental purposes, without the payment to me of any royalty thereon. with a hexagonal portion 6 to which a tightening This invention relates to improvements in wrench is applied and a crimped over portion 8 spark plug construction whereby it becomes poswhich locks the insulator 2 within the body I. In sible to modify a standard automotive type spark order to keep the cost of manufacture low, the plug construction to render the same applicable body 3 is turned from hexagon bar stockwluch, to the construction of shielded or unshielded of course, leaves the gasket seat portion 5 w1th a spark plugs for aircraft ngine ignition and there- It) hexagonal pgriphery. 2211611 plugstlof tll ns type by effect a considerable saving in cost. are emp oye on aircra engines e c ampmg The plug bodies of aircraft type spark plugs pressure exerted by the seat 5 on the soft gasket differ from those employed in automotive pracring 1 causes indentations at the corners of the tice mainly in that aircraft plug bodies are formed hexagonal sides of the seat 5, and after the plug with a larger diameter gasket seat to effect a has been e d a replaced a few es the proper seal to prevent leakage at the higher comgasket becomes chewed and distorted and will no pression pressures employed in aircraft engine lonier3 prlolpefily sgal, reqfi l ie gwg b f the cylinders. Since it is not possible to form the g 6, 0 1S equen y o 00 6 y plug body directly from hexagonal bar sto k t chanics. If the gasket section? were turned to give the requisite gasket seat diameter Without a Ci ular form, the diameter ofth gasket W0l1 also increasing the dimensions of the hexagonal be inadequate tic propgerily distribulte 1the sealing portion of the plug body where a wrench is appressure, d 8 gas 6 Seat W011 (1 d 0 plied beyond standard dimensionsJt has been the dent 2% gasket; and'ciif thlelbody of i P Were practice to form th lug bodies of round b forme y urning an m1 mg so as 0 ive a cirstock and then mill .the hexagonal portions of Gular gasket seat of the requisite diameter, the the plug body, which materially increases th cost of manufacture would be greatly increased cost of manufacture, and production would be limited due to increased In accordance with the present invention and machining timeconstituting its primary object, the spark plug In accordance with the invention, the problem body is formed 1mm hexago al bar Stock in a of forming a gasket seat which W111 not damage manner similar to the formation of an automothe plug gasket and st 111 allow the P y t tive plug bgdy but isdso lmachlgnid that a separate 2:; 523 32 2 8 i l igrsririlgiggon baif" stock (21 a scgew ring may e presse s run razed, or welded mpne 01min gure m thereon to give the necessary gasket seat diamewhlsh f ii f pgrlghery oftthe i t 88:17 ter. t 35 par ion 0 e put; 0 y 3 is urne own 0 The features of novelty of the invention will be form? Shoulder onto which is p ess d an ennuiurther apparent by reference to the detailed deg, or washer whlch t face scription hereinafter given and to the appended s f i g i 2,2 gg i f portion of drawing, in which ns ruc ion gives a t Figure 1 illustrates a conventional automotive 2 55;: fig ifi 53 13 and i circuiarflclontolir ype of spark plug; S al y amage 0 e sea t Figure 2 illustrates one form of a plug similar gi ggfiifi g fig gi 2 1 3 2 3 an engine 0 t at of Figure 1, modified in accordance with 6 any the invention; berlof time; without requiring replacement of the a fragmentary w of portion of z i ggri il l strates to an enlarged scale a modi gz i 8 g g fiifif i further fled construction in which the projecting portion Figure 4 is a View Similar to Figure 3 muscrab of the gasket seat 5 1S turned on flush th t plug body and an annular ring 10a placed theremg another Vamtlon of the on' with a light push fit so that he r t f In the appended drawing, Figure 1 illustrates f the ring ma is flush with the of i a a Fonventiona] spark plug which may be seat 5. The rear face of the annular ring lfla is tamed at low cost, havingthe insulator 2 mountchamfered as at l i and this chamfer is filled with ed ma metal body having a threaded portion brazing metal 12 which may be applied in paste 4 which is screwed into the engine spark plug form and melted in a hydrogen atmospherefuraperture, and having a hexagonal portion 5 which serves as a gasket seat for a conventional gasket ring of soft copper l.

The body 3 is provided nace at the same time the plug body electrodes are brazed in place. This construction has the same advantages as above described with reference to Figure 2.

Figure 4 illustrates a further modification which is similar to the device of Figure 2 except that the projecting portions of the gasket seat 5 are left oil? and the annular ring lflb is made of a suflicient length to abut the hexagonal portion 6 of the plug body. The ring 10b may be pressed or shrunk on the plug body 3 and also may be brazed in the manner illustrated in Figure 3-.

While the invention is shown as applied to unshielded spark plugs, the invention is similarly applicable to shielded spark plugshaving a tubular shielding extension formed as an integral part of the plug body and this will allow the shielded plug body to be made from hexagon bar stock as distinct from the present procedure of forming the plug body from round bar stock and milling the hexagonshape for application of thewrench.

While preferred forms. of the invention have been illustrated and described, other modifications and variations thereofwill become apparent tothose skilled in the art as coming within the scope oi the invention as: defined inthe appended claims.

I claim:

1 In aspark plug construction of the character wherein the plug body is made from hexagonal metal bar-stock and has a hexagonal portion for the application of a tightening wrench and a portion joining said hexagonal portion having an endfaoe forminga sealing gasket'seat: the

improvement which comprises providing a, circular shoulder on said gasket seat portion concentric with the axis of the plug body and an annular ring secured on said shoulder and extending radially beyond said gasket seat portion, an end face of said ring forming a continuation of said gasket seat face.

2. In a spark plug construction of. the character wherein the hollow plug body is made of hexagonal metal bar stock and provided with a threaded portion for insertion in an engine cylinder, ahexagon portion for application of a wrench and a third portion intermediate said first named portions, said third portion having a radially extendingv end. face forming a gasket seat: the improvement which comprises securing an annular ringon said plug body portion concentric with the longitudinal axis of said plug body, said ring having, an outside diameter greater than the diameter of said third portion and having an end face: forming: a continuation of the gasket seat face of said plug body third; portion.

Bl The, structure'as claimed inclaim 2, in which the plug body third portion is cylindrical, said ring-"being seated on. the said cylindrical portion of the plug body and: an end face of the ring being flushwith the gasketseat face of the said

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