US2519850A - Radio shielding sealing gasket - Google Patents

Description

Aug. 22, 1950 A. A. PIERSON, JR

RADIO SHIELDING SEALING GASKET Filed March 22, 1945 Patented Aug. 22, 1950 UNITED STATES PATENT OFFICE I 2,519,85c v RADIO :SHIEIDING SEALINGV GASKET Adrian A. Pierson, Jr., Utica, N. Y.

Application March 22, 1945, SerialNo. 584,153

lf In the ignition systems of internal combustion enginesused in airplanes, motor vehicles and the like, high tension current passes within the distributor in the `forrnoi'asparlcbetween .a cen- Vtral;or: main terminal andaterminal for each cylinder in the engine. These terminals between which theVv sparks occur are enclosed in the distributor by a cap which ts over the body thereof Iand, in the case 0f airplanes; both the body 'and the cap areoi metal. To'prevent interference jwith the radio with which such vehicles are I'equipped `it is necessary to'p'revent-the waves genjerated'by these sparks from` passing outside of the distributor. Furthermore,` it is not only es sential thatentrance of water'b'etween-the cap and the lbody ofthel distributorbe prevented but la'lso air leakage from the interior of the distributor, because 4the air` pressure within the distributor usedin planesthat riseto high altitude must be maintained substantially higher, by supercharging than the* pressure of the circumambient air.' j It isa' relatively simplematterto prevent the electro-'magnetic waves generated by the'sparks aforesaid from passing outside the distributor by providing a substantially continuous metal contact between the cap and the body of the distributor. It is also a rather simple matter to provide 'a substantially air tight contact between the distributor cap and body so that an air pressure which is substantially higher than that of the circumambient air can be maintained within the body of the distributor. However the problem of providing good electrical contact between the cap and the -body of the distributor, which involves the use of metal in some form or other, and, at the same time, forming an air tight contact between the cap and the body of the distributor is somewhat more dimcult of solution. A gasket which can be used to eiect such a combined radio shield and air seal must be adapted to be manufactured rapidly at `comparatively low cost; must be yielding, and preferably resilient to an appreciable degree to conform to 'and thereby form an air tight seal with the surfaces between which it is positioned; must be air impervious; and must provide a substantially continuous metallic contact between the cap and body of the distributor.

It is the principal object of my invention to provide such a gasket and I accomplish this result by forming the gasket in the manner described below and illustrated in the accompanying drawing in which:

Fig. 1 is a fragmentary elevation View to a greatlyenlarged' scale of my preferred form' of gasket;

Fig. 2 isi afragmentary cross section ofmy preierred'iorni of gasket toa still greater'enlarged scale;

Figs; 3 and-'4 are fragmentary sections similar to 2 showing modified types of gaskets; and

Fig. 5 is a. fragmentary elevation viewtoan enlarged scale of one of the elements forming my preferred type ci gasket.

Referring to the drawings irepresents thecore of the gasket whichis preferably cylindrical and formed of rubber, or preferablwNeoprene or some similar substance which isV resilient and deformable, so thatit can function as agasket, and yet moreresistant to the action ofl oils-and greases than is rubber,

Wrapped around this core is a plurality' oflelectrical conductors having closely spacedportions thereof exposed'on the surface of the gasketl so asv to provide a substantially continuous electrical contactfbetw'eenthe two metallic surfaces between Awhich the gasket is compressed. These conductors'are preferably braided together as shown at 6 in Fig. 1. The preferred form of conductor is shown in Fig. 5 and comprises a core 8 of fibrous material such as thread or yarn around which is helically wrapped a very thin gauge, fiat, metal ribbon 1. In Fig. 3, however, I have shown a wrapping formed entirely of metal conductors 2 which may be very fine wires. It is to be understood that the conductors which are wrapped about the core are extremely tenuous and are not intended to, and do not, function as an armor or protection for the core, but only to provide electrical conductivity between opposite sides of the gasket substantially throughout.

In Fig. 2, I have shown a gasket formed by wrapping .a plurality of conductors 6, such as shown in Fig. 5, around a core l of rubber, neoprene or the like. Here, it will be apparent that the metal ribbons which are wrapped around the threads 8 are exposed on the surface o-f the gasket.

In Fig. 4 I have shown a wrapping comprising wires 4 and threads of yarns 5. As here shown, the Wires `and threads alternate, but it is to be understood that groups of two or more wires and groups of two or more threads may be braided together; the important thing being that closely spaced portions of the wires, or other conductors employed, be exposed on the surface of the gasket to provide substantial continuity of electrical contact between two metallic surfaces in contact with said gasket but on opposite sides thereof.

As thus formed, it will be apparent that none of the gaskets when compressed will be absolutely air impervious because of the interstices which exist between the conductors themselves, between the conductors and the core and in the yarns or threads if such are employed.

Therefore, in order to make the gasket air impervious throughout I immerse it or run it through a dispersion or a solution of an air irnpervious material, such for example, as rubber or latex, in a suitable solvent so that all of the interstices in the gasket are filled thereby as shown at 3 in Figs. 2, 3 and 4. When the gasket is removed from the impregnating bath the solvent evaporates leaving the interstices filled with air impervious material. The lm of rubber or other air impervious material used in impregnating which adheres to the surfaces of the conductors which are exposed on the surface of the gasket may be removed by suitable wipers or,

preferably, by drawing the material through a die.

As pointed out above the drawings are to a greatly enlarged scale, and while the invention is not limited to any particular size of gasket it may ybeunderstood that, in practice, the overall diameter would not ordinarily exceed about lg.

What I claim is: l. A radio shielding and sealing gasket comprising a core of resilient material in the center thereof, a plurality of metallic conductors, cornprising thin, flat, metal ribbons helically wrapped about' tenuous strands of yieldable material,

Aclosely braided around said core and having closely spaced, bare portions of said ribbons exposed substantially throughout the entire surface of said gasket, and the interstices of said gasket being substantially lled with a resilient, air-impervious substance preventing passage of air transversely through said gasket; whereby, when 1 said gasket is compressed between two surfaces spaced thereby, said surfaces will be in substan- .tially continuous electrical contact through said vgasket and the space between said surfaces will be effectively sealed against the passage of air and moisture in the zone of said gasket.

' 2. A radio shielding and sealing gasket comprising a core of resilient material, a plurality of electrical conductors, comprising tenuous strands of brous material having thin, at, metal ribbons helically wrapped about them., braided closely together around said first mentioned core with closely spaced, bare portions of said ribbons exposed on the surface of said gasket, and the interstices in said gasket bein-g substantially lled with a yielding, air-impervious material preventing passage of air transversely through said gasket; whereby, when said gasket is compressed between two surfaces spaced thereby said surfaces will be in substantially continuous electrical contact through said gasket and the space between said surfaces will be effectively sealed against the passage of air and moisture in the zone of said gasket.

.ADRIAN A. PIERSON, J R.

REFERENCES CITED The following references are of record in the le of this patent:

Y UMTED STATES PA'I'ENTS Number 115,567 `Australia, July 16, 1942

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