US1301862A

US1301862A - Spark-plug.

Info

Publication number: US1301862A
Application number: US25141218A
Authority: US
Inventors: Jeremont J Macbeth
Original assignee: Individual
Current assignee: Individual
Priority date: 1918-08-26
Filing date: 1918-08-26
Publication date: 1919-04-29
Anticipated expiration: 1936-04-29

Description

1. l. MACBETH.

SPARK PLUG.

APPLlcATloN FILED Aue.26. 19m.

Patented Apr. 29, 1919.

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NVEJVTOR. Waclftyx BY /f AUTOR :milonic J. HACBETH, or DAYTON, onto.

snm-PLUG.

' Specification of Letters Patent.

Application med August 26, 1913. Serial No. 251,412.

i To all what?, t may concern.'

Be it known, that I, J EREMoNT J. M Ac- BETH, a citizen, of the United States, residui at Dayton, in the county of Montgomery an State of Ohio, have invented certain new and useful Improvements in Spark-Plugs, of which the following is a speclication. E

My invention comprises an improved `spark plug of the type used in connection with gas engines. l

The object of the invention 1s to improve the method of manufacture of spark plugs with a view to simplifying the same and reducing the manufacturing cost, and at the same time provide a durableand highly eili-` cient spark plug. g The improvements have to do more specially with the mounting of the insulator bodies whereby a minimum use` is made of screw thread connections and the work of assembling the parts is `relatively simple, and efficiency is preserved.

A knowledge of the invention w1l1 be readily gained from the following description thereof in connection with theaccompanying drawing which is a longitudinal sectional elevation made upon a scale somewhat larger than the actual size of the spark plug in order to more clearly illustrate the elements thereof.

Referring more? specifically to these elements, 1 designates the outer shell or main bod of the Plug, the upper end terminating in t e form of a dome 1. The lower portion of said shell or main body is provided with exterior `screw threads 10 for attaching the plug to the cylinder of an engine (not shown). The body of said shell or body is provided with an enlarged portion` in the4 form of a nut 2 by which the attachment is made with the cylinder of thel engine, this nut 2 being formed integral with said shell. 3 desi ates an internal body of insulation, such or example, as porcelain. The lower portion of this porcelain .body 3yis enlarged to conform to the dome shaped character of `the outer shell in which it is housed. The

upper portion of said insulator 3 is reduced in diameter and extends above and out of I the internal insulator 3. The upper end of the dome-shaped' end of the outer shell. 4

the insulatorfbody 4 is provided with a recess 16 which is larger in area thanthe portion of the internalinsulator body 3 pro- ]ects. Within the space between the internal insulator 3 and the body or outer shell 1` and the space between the upper portion of the internal vinsulator 3 and the outer insulator portion 4 cementitious material 'Z and 5 is placed for the purpose of tightening or `sealing the respective bodies together. 8

designates a terminal stem or electrode which passesy through the internal insulator 3 and the nut 12 and holds or supports the said in ternal insulator?, by an, integral collar` 9 formed on said stem below the said insulator. The upperportion of the electrode or Patented Apr. 29, 1919.

y opening of said body 4=-into which the upper4 stem 8,is provided with screw threads 13 which are engaged by the nut 12. The nut 12, as before stated, is received by the recess 16 in the upper end of the outer insulator body 4 and the same is instrumental in supporting the electrode 8 and the internal insulator 3 in position,` said nut engaging the annular shoulder 17 which is formed atthe j bottom of the recess 16. The space between rbody 1 and pointing in proximity to the end of the stern or electrode 8 and providing in connection therewith the sparking point 16".

From the description given above it will `be seenthat the internal insulator 3 is inserted into the outer shell orbody 1 through the end having the larger opening and that it is held securely in position therein ina manner which provides for a requisite amount of co-eiciency of eX ansion and contraction. It will also be o erved that `any tapered or contracted areas are not depended upon to contribute to holding the internal insulator in" position. It may be stated here that while the matching surfaces between the outer shell or main body and the internalY and external insulators are shown to be of rounded or of dome-shaped form it will be apparent that these matching sur? faces might be made of a tapered or beveled i character. It is thought, however, that the rounded form is more preferable.

Havingdescribed my invention, I claim: In a spark plug,the combination of an g e a 1 .1,301,832 i outer shell having a` rounded end, an inner` ed end of theouter shell and into whiohthe insulator body fillingvthe rounded end of' reduced portion of the innerinsulator pro- 1o said shell andY having o. reduced portionof J and a nut engaging said electrode uniform diameter extending beyond said mem r and' supporting the same on said '5 end, a. straight electrode member extending, puter insulator body.

through said inner insulator body and the In testimony whereof Iax my signature. reduced extended portion thereof,an 'outerv I insulator body formed to receive the rou'nd- JEREMONT J.A MAOBETH.