US1232039A - Spark-plug. - Google Patents

Description

B. A. JEFFERY SPARK PLUG.

Patented July 3, 1917.

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BENJAMIN A: JEFFERY, OF DETROIT, MICHIGAN.

' SPARK-PLUG.

Specification of Letters Patent.

Patented July 3, 1917.

- Application filed December 9, 1913. Serial No. 805,569.

To all whom it may concern:

Be it known that I, BENJAMIN A. JEF- rnRr, a citizen of the United States, residing at Detroit, in the county of Wayne and State of Michigan, have invented new and useful Improvements in Spark-Plugs, of which the following is a specification.

This invention relates to an improved spark plug.

One of the objects of the invention is to provide improved means for supporting the insulating block of a spark plug. A further object is to provide means for maintaining a tight joint between the insulating block and a supporting element connected therewith, whereby the separating influences of the pressure of the fluids or gases to be retained, are resisted. A further object is to provide means by which the initial strains to be placed upon the porcelain insulating block for the purpose of securing a tight joint, may be predetermined and regulated. A further object is to provide an improved packing between the porcelain insulating block andits'supporting bushing, said acking having substantially the same coe cient of expansion as the material forming said insulating block. A further object is to provide means for preventing torsional or other strains, on the insulating block, which manipulation of the securing bushing might set up. A further object is to provide means for reinforcing the insulating block.

The invention will be hereinafter fully set forth and particularly pointed out in the claims. I

In the accompanying drawings Figure 1 is a longitudinal sectional view of a spark plug constructed in accordance with my invention. Fig. 2 is a similar-view of a slight modification. Figs. 3 and 4 are opposite end views. Fig. 5 is a detail view illustrating the ferrule.

Referring to the drawing, 10 designates a shell provided with the usual screw threads 11 for engagement with the engine casing. Said shell is provided with a longitudinally tapered bore 12 provided with an annular shoulder-2.13, the upper portion of the bore being screw threaded, as indicated at 14:.

The threaded portion 14 is arranged to engage a correspondingly threaded portion of the usual bushing 15.

The insulating block 16 is made of suit.- able material, preferably porcelain, and

a ferrule 22, the edges of which are bent over the respective flanges to prevent separation thereof. It will be noted that the bushing 15 is provided with a bore to receive the insulating block and collar 19, said bore being large enough .to provide a slight radial clearance for the. packing. The bore 12 of the shell 10 is large enough to provide 'a slight radial clearance for the packing ring 20. Likewise, that part of the shell which incloses the flanges 21 also provides radial clearance for said' flanges and the ferrule which surrounds them.

In practice the parts are assembled in the following manner :The packing collars 19, 20 are forced, from opposite ends, longitudinally on to the double cone or tapered portions 17, 18, until the flanges meet. The ferrule is then put over the flanged portions of the two packing collars, being in the form illustrated in Fig. 5, and the open end turned inwardly, thus causing the ferrule to envelop the three exposed surfaces of the flanges 21. The flanges and ferrule thus form a rigid non-yieldable supporting member of tubular form to engage and sustain the insulating block, and having a flange midway of its ends, whereby it may be supported. The porcelain with the two continuous contact is possible; and second,

by bringing these surfaces together with sufficient force to resist the separating influblock and also by providing suflicient area of cross section in the parts to furnish the necessary strength. An alloy of the character referred to is described in Letters Patent 626,609.

The insulating block 16 is provided with a central electrode 25 embedded therein provided with a sparkingpoint 26 cooperating with a grounded electrode 27 carried by the shell'10. The electrode 25 is also provided at its other; end with a binding post 28 of any suitable or preferred construction.

In Fig. 2 I have illustrated a slight modification, which consists principally in dispensing with the bushing 15 by means of which the insulating block is removably supported by the shell 10, and substituting therefor a ring or spacing piece 29 which rests upon the flange 21. This collar is forced. longitudinally toward the shoulder 13, by crimping over the thin edge 30 on the upper portion of the shell, enough pres sure being exerted to force the lower face of the flange 21 into a gas tight joint with he the shoulder 13. It will be understood that art .to which it appertains.

in this form of the invention a slight radial clearance is pr vided between the flange 21 and the bore O F thG shell is provided.

The advantages of my invention will be readily understood by those skilled in the the constructions herein illustrated and described, the strain, which might be called the initial strain to be put upon the porcelain insulating block for Q16 purpose of securing a tight 3' o1nt, can be predetermined and regu-v lated by the relative sizes of the bores of the packing collars and the shoulderof the porcelain itself; also the thickness of the metal in the packing collar, to give only so much resistance to leakage and mechanical strains as is necessary to prevent the former and keep the latter from causing any disarrangement of the parts of the plug. By means of my invention, also, any torsional straining of the porcelain insulating block, such as could be caused by the tendency of one packing collar to twist in relation to the other, were the bushing to screw down directly onto the upper packing collar, is prevented by the use of the ferrule'which takes this strain. Said ferrule being made of soft metal-acts as a gasket between the lower By means of.

packing flange and the internal shoulder in the shell. The use of the form of packing ring herein described results in a very great increase in the effective strength of the porcelain, both on account of the elimination of unnecessary strains and the reinforcement afforded by the extension of the packing collar above the usual point of support, as more fully appears in the form illustrated in Fig. 2.

Having thus explained the nature of my invention, and described an operative manner of constructing and using the same, although without attempting to set forth all of the forms in which it may be made, or all of the modes of its use, what I claim 1s:

1. An improvement in spark plugs comprising a supporting shell, an insulating block provided with an electrode, rigid pacl ing having a tubular portion surrounding said block and having an inseparable frictional engagement therewith, the periphery of said packing being provided with a rigid unyielding annular portionintermediate of the ends of the tubular portion for supporting the insulating block within the shell, means engaging said flange to retain the insulating block within the shell, and a second electrode carried by the shell.

2. An improvement in spark plugs comprising a supporting shell, an insulating block provided with an electrode, oppositely disposed independent packing collars connected with said insulating block and provided with rigid unyielding abutting portions supporting the latter within said shell, and a second electrode carried by said shell.

3. An improvement in spark plugs comprising a supporting shell, an insulating block provided with an electrode, oppositely disposed independent packing collars con nected with said insulating block and provided with. rigid unyielding abutting portions supporting the latter within said shell, means enga 'ng said collars to retain said insulating b ock within said shell, and a second electrode carried by said shell.

4. An'improvement in spark plugs comprising a supporting shell, an insulating block provided with oppositely tapered surfaces,- an electrode within said block, oppo-. sitely disposed packing collars forced upon the respective tapered surfaces of said 'insulating block and provided with abutting annular flanges for supporting said insulating block, and a second electrode carried by said shell.

t An improvement in s ark plugs comprising a supporting she an insulating block provided with oppositely tapered surnaaaose annular flanges for supporting said insulating block, a ferrule uniting said flanges, and a second electrode carried by said shell.

6. An improvement in spark plugs comprising a supporting shell, an insulating block provided with oppositely tapered surfaces, an electrode within said block, oppositely disposed packing collars forced upon the respective tapered surfaces of said insulating block and provided with abutting annular flanges for supporting said insulating block, means engaging said flanges to retain the insulating block within said shell, and a second electrode carried by said shell.

7. An improvement in sparkplugs comprising a supporting shell, an insulating block provided with oppositely tapered surfaces, an electrode within said block, oppositely disposed packing collars forced upon the respective tapered surfaces of said insulating block and provided with abutting annular flanges for supporting said insulating block Within said shell, a ferrule uniting said flanges, a bushing engaging said shell and said ferrule to retain said insulating block within said shell, and a second electrode carried by said shell.

@An improvement in spark plugs comprising a supporting shell, an insulating" block provided with oppositely tapered exterior surfaces, oppositelydisposed packing collars forced upon the respective tapered surfaces, means engaging said packing to retain said insulating block Within said shell, and electrodes carried by said insulating block and said shell, respectively.

9. An improvement in spark plugs comprising a supporting shell, an insulating block provided with oppositely tapered exterior surfaces, oppositely disposed packing collars forced upon the respective tapered surfaces and provided with abutting annular flanges, means engaging said flanges to retain said insulating block within said shell, and electrodes carried by said insulating block and said shell, respectively.

10. As an improvement in spark plugs, an

insulating block provided with a central insulating block provided with an electrode and having exterior packing collars secured thereto and provided with abutting flanges, and a ferrule uniting said flanges, said col lars having the same coeflicient of expansion as said insulating block.

18. As an improvement in spark plugs an insulating block provided with an electrode and having exterior oppositely tapered surfaces, abutting packing collars having an inseparable frictional engagement with said surfaces, and means for uniting said packing collars, said collars having the same co efficient of expansion as said insulating block.

In testimony whereof I have hereunto set my hand in presence of two subscribing witnesses.

BENJAMlN A. JEFFERY.

Witnesses:

JOSEPH ARTHUR JEFFERY, FRED. L. PARKER.

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