US2174978A

US2174978A - Spark plug

Info

Publication number: US2174978A
Application number: US234850A
Authority: US
Inventors: Willard M Hart
Original assignee: Individual
Current assignee: Individual
Priority date: 1938-10-13
Filing date: 1938-10-13
Publication date: 1939-10-03
Anticipated expiration: 1956-10-03

Description

Oct. 3, 1939.

.W M. HART SPARK PLUG Filed Oct. 13, 1958 Patented Oct. 3, 1939 UNITED STATES PATENT OFFICE 1 Claim.

This invention relates to the class of ignition devices for explosive engines and, pertains particularly to improvements in spark plugs.

Operators of internal combustion engines such as automobile engines are aware that adjustments frequently have to be made of the electrodes or sparking points of the spark plugs in order that the particular cylinder 01' each spark plug may operate at maximum efliciency. Such adjustments are primarily required as a result 01' the burning away or pitting of the electrodes although it may be found that the initial setting for the points or electrodes of the plug is not correct for the particular cylinder in which the plug is used. When such a change in the setting 01' the electrodes is necessary, the ordinary plug has to be removed from the cylinder and the points 01' the electrodes bent to bring them into'proper spaced relation and then the plug must be put back and the engine operated to determine whether the setting is correct.

The present invention has for its primary object to provide an improved spark plug whereby an adjustment of one electrode relative to the other may be readily made without necessitating removing the plug from the engine cylinder, thus making it possible to keep the engine running while adjusting the electrodes so that it can be readily determined by the manner in which the engine is running just when the adjustment has been correctly made in order to obtain maximum operating efliciency from the cylinder in which the particular plug under consideration is located.

Another object of the invention is to provide an improved spark plug wherein the center electrode and porcelain carrying thesame may be longitudinally moved through the shell which is threaded into the engine cylinder head and which carries the grounded electrode, thus making it possible to adjust the electrodes without'running the risk of receiving a shock as the part of the plug which must be touched for the purpose of {)noaking the adjustment is grounded to the engine The invention will be best understood from a consideration oi. the following detailed description taken in connection with the accompanying drawing iorming part of this specification, with the understanding, however, that the invention is not to be confined to any strict conformity with the showing of the drawing but may be changed or modified so long as such changes or modifications mark no material departure from the salient features of the' invention as expressed in the appended claim.

In the drawing:

Fig. 1 is a view in side elevation of the spark plug embodying the present invention.

Fig. 2 is a longitudinal section throughthe same and through a portion only of the center electrode 5 porcelain.

Fig. 3 is a Fig. 2.

Referring now more particularly to the draw ing, the numeral I designates a portion of an engine cylinder head in which is the usual threaded opening 2 for the reception of the lower or base portion of a spark plug.

The spark plug of the present invention comprises a metallic base or shell body 3 having an enlarged upper end portion of polygonal contour as indicated at 4 to facilitate the attachment of a wrench or similar tool thereto so that the reduced lower end portion 5 of the shell which is screw threaded as indicated at 6, may be threaded into the opening 2 of the cylinder head.

The usual passage I is formed through the shell and the upper end of this passage is of enlarged diameter as indicated at 8 and screw threaded as indicated at 9.

The lower edge of the shell 3 has secured thereto the usual ground electrode III which in the present structure has a terminal upwardly directed portion II which is disposed approximately upon the longitudinal center of the plug body.

Threadably secured in the portion 8 of the shell 3 is a sleeve l2, the lower end of the exterior being threaded as indicated at ii for engagement with the threads 9 and the upper end of the interior being threaded as indicated at It for engagement by the exteriorly threaded end of a packing collar IS. The lower interior portionof the sleeve I2 is formed to provide a shoulder IS on which the usual packing ring I! is placed and this ring and shoulder support the central electrode porcelain body l8 which extends longitudinally through the sleeve l2 and through the major upper end portion of the shell 3 as illustrated. This porcelain body has the usual enlarged central part I9 which provides upper and lower shoulders, the lower one of which rests upon the packing ring I! as illustrated, while the upper one has pressed thereagainst the packing ring 20 by the collar l5 which surrounds the porcelain.

Through the center of the porcelain body the primary electrode 2| passes, the lower end of this electrode being in spaced relation with the upwardly directed end of the grounded electrode It. The uppenend of the electrode 2| is formed in sectional view on the line 3-4 of in the threaded aperture of the engine cylinder head and the looking or binding nut 23 is loosened or backed away from the upper end of the shell so that the sleeve, to which the central electrode carrying portion [8 is firmly fixed, may be rotated and thus moved, and move the center electrode and porcelain, longitudinally. This longitudinal movement of the central electrode will, of course, change the distance between the lower end of the electrode and the grounded electrode 10 and when it has been determined by the running action of the cylinder in which the plug is secured when the cylinder is operating at greatest efficiency, the binding or lock nut 23 is then screwed down into tight engagement with the upper end of the shell 3 while holding the sleeve l2 against rotation. The sleeve, together with the porcelain and center electrode, will then be firmly fixed and if, after the electrode points have become pitted or for any other reason further adjustment is necessary, the nut 23 may be loosened and the described procedure repeated until the cylinder is again operating properly.

What is claimed is:

A spark plug of the character described, comprising an elongated cylindrical base shell having one end exteriorly threaded for connection in the spark plug opening of an engine cylinder, the other end of the shell being interiorly threaded, a sleeve having an exteriorly threaded portion for engagement in the interiorly threaded end of said shell, said sleeve being interiorly reduced at the said threaded end, an elongated body .of in sulation having a portion of maximum diameter substantially midway of its ends and extending through said sleeve with the said portion thereof disposed in the sleeve and supported therein upon the part of reduced diameter, the portion of the insulation body extending through the sleeve portion of reduced diameter extending through the major portion of the shell and terminating short of the end thereof which enters the engine cylinder opening, an electrode extending longitudinally through said body of insulation, a locking ring encircling and having threaded engagement with said sleeve and adapted to bear against the top end of said shell to maintain the sleeve in adjusted position therein, and a clamping ring encircling said body of insulation and threadably engaging the interior of said sleeve to secure the insulation body therein, and a ground electrode integral with the shell and having spaced relation with the inner end of said first electrode.

WILLARD M HART.