US1856001A - Spark plug - Google Patents

Description

April 26,.1932.

N. SPINELLII SPARK PLUG Filed May 19 1930 jvzcozmSfl/vzw INVENTOR ATTORNIY Patented Apr. 26, 1932 UNITED STATES PATENT OFFICE NICOLA SPINEL-LI, OF NEW YORK, N. Y., ASSIGNOB OF ONE-HALF 1'0 CARLO DALESSIO,

' OF NEW YQRK, N. Y.

SPARK PLUG Application filed May 19,

This invention relates to spark plugs, and the principal object thereof is to provide a new and improved spark plug having, at once, the advantages of includlng a readily attachable central electrode, of exhibiting high compression holding qualities under all conditions, and of incorporating comparatively few and relatively inexpensive parts.

Other'objects and advantages of the invenm tionwill be hereinafter specifically pointed out, or will become apparent, as the specification proceeds.

With the above indicated objects in view,

the invention resides in certain novel constructions and combinations and arrangement of parts, clearly described in the following specification and fully illustrated in the accompanying drawings, which latter show an embodiment of the invention as at present preferred.

In said drawings:

Fig. 1-is, on rather a large scale, an axial section of said embodiment, with the two electrodes, however, in elevation;

Fig. 2 shows the center electrode, exactly as seen in Fig. 1, but alone;

Fig. 3 shows, partially in axial section, and partially in elevation, a metal sleeve, for coacting with said center electrode as indicated in Fig. 1; and

Fig. 4 is an axial sectional view, partly in elevation of the metal bushing which cooperates with the sleeve and electrode.

Similar reference characters refer to similar parts throughout the several view of the drawings.

Referring now more in detail to the embodiment illustrated in said drawings, the spark plug of the present invention preferably includes, as is well known in the art, a metal shell 6, and an electrode 7 carried thereby, a core 8 of porcelain or the like for sleeving the center electrode, hereinafter to be more particularly described, gaskets 9 and 9a, and a nut 11; such nut externally threaded and screwed into the upper internally threaded portion 6' of the shell, for compressing the gaskets 9 and 9a and thereby clamping the porcelain core within the shell, tightly and in a manner to avoid compression leakage and 1930. Serial No. 453,785.

yet without danger of cracking of fracturing the core.

Said shell 6 may, externally, be of conventional shape, and will desirably include a wrench head as indicated at 6 and an external screw thread 6a, whereby in the usual way the spark plug may be mounted on the cylinder head or other supporting body.

The core 8, in the present case, has a lower most narrow cylindrical bore 10; and above this bore 10 is a bore 10d of large enough diameter to receive the bushing 12 next to be described,this bore 106 being internally threaded down through almost its entire length as illustrated.

The bushing 12 (Fig. 4) is of metal and has an external thread 106 matching the internal thread in bore 10d of the porcelain core. The bore 13a of the bushing 12 is rounded spherically as indicated at 12' near its bottom, and below this rounded seat 12 said bore is continued as a lesser bore 12". The main or upper bore of the bushing 12 is internally threaded, from its top down slightly more than half way of its length, as indicated at 13. The bushing 12 has a head 12a provided with a cup 120 having a plane bottom perpendicular to the cylindrical inner wall of the cup side In this instance the bushing bore portion 13 is adapted to receive a threaded sleeve 18, into which sleeve 18 the upper threaded end 15a of the center electrode 15 has been previously threaded the sleeve 18 having a bore 150 including an in ternally threaded portion 15?) for this purpose. V

The center electrode 15, which is of course of metal and preferably integral from end to end, incorporates midway of its ength a sphere 14c, of the same diameter as the rounded seat 12 in the bottom of bushing 12; and the said electrode also includes, below the sphere 14 an elongated portion 17 acting asv a sparking end of the center electrode; and this portion 17 is cylindrical, like the portion 170: at the opposite side of the sphere 14.

As the parts are shown assembled, the end 17 of the center electrode acts as the s arking end of that electrode and protrudes elow (ill the lower end of core 10, in sparking position relative to the adjacent end of electrode 7. It will be noted that the threaded portion 15a of the center electrode has been screwed up into the threaded portion 15b of the sleeve 18. This has seated the sphere 14 in the rounded portion 12a of sleeve 18. The sleeve 18 is then threaded into the bore 13 of bushing 12 so that the sphere 14 seats in the rounded bottom of bushing 12. All the parts are nicely machined and to an ex tent such that any compression leak along the lengths of any of the bores for the center electrode will be absolutely stopped by the clamping together tightly of the parts 14, 12a and 12.

The spark plug is completed, for the attachment of a conductor in the familiar way to a threaded terminal 18 constituting the upper end of the metal sleeve 18, the sleeve terminal 18 being provided with a lock nut 18a. This lock nut 18a cooperates with a nut 185 provided at the upper end of the sleeve 18 for this latter purpose. Also, the

nut 18 is preferably polygonal in "form, for

manipulation by a wrench or the like in securing the sleeve in place; and, as seen in Fig. 1, the nut 185 seats in the cup portion 12a of the bushing 12 when the parts are assembled,

When the center electrode is to be replaced, it is merely necessary to unscrew and remove the sleeve 18, and rein-sert a new center electrode, and screw the sleeve down into place again within the bushing 12.

The hereinbefore described construction admits of considerable modification without departing -from the invention; therefore, it is the wish not to be limited to the precise arrangements shown and described, which are as aforesaid, by way of illustration merely. In other words, the scope of protection contemplated is to be taken solely from the appended claims, interpreted as broadly as is consistent with the prior art.

What is claimed as new'is:

1. In a spark plug, the combination with a shell, an insulator, and means -for securing said insulator within the shell, oi a center electrode having a spherical enlargement intermediate its ends, and a mounting therefor in said insulator, said mounting including a bushing having a rounded seat to lit against one portion of said spherical enlargement,

signature.

NICOLA SPINELLI.

Images