US2316504A

US2316504A - Radio shield

Info

Publication number: US2316504A
Application number: US400531A
Authority: US
Inventors: Ward D Dayton
Original assignee: Breeze Corp Inc
Current assignee: Breeze Corp Inc
Priority date: 1941-06-30
Filing date: 1941-06-30
Publication date: 1943-04-13
Anticipated expiration: 1960-04-13

Description

April 13, 1943. w. D. DAYTON RADIO SHIELD 2 Sheets-Sheet l Filed June 50, 1941 l imilll w i M III 4 INVENTOR M/ARD B fin wow k 40a:9 ATTORNEYS April 13, 1943. w. D. DAYTON RADIO SHIELD Filed June 30, 1941 2 Sheets-Sheet 2 ATTORNEYS INVENTOR WA RD D DAY To/v Y .lrl llv hiw "U. ni'umj .59/4. .1 I III. 2 a; 1 u/47 1..

a. W A 4 3 Patented Apr. 13, 1943 RADIO SHIELD Ward D. Dayton, Bloomfield, N. J., assignor to Breeze Corporation, Inc., Newark, N. J.

Application June 30, 1941, Serial No. 400,531

19 Claims.

This invention relates to radio shields for ignition systems of internal combustion engines. These shields are employed to prevent interference with operation of radio equipment by electrical emanations from the engine ignition system. The presence of moisture or water in the shields will cause ignition and engine trouble, and the principal object of the invention is the provision of means to insure against accumulation of moisture or water in such shields and interference thereby with functioning of the spark plugs and engine.

In the manufacture of radio shields, or harnesses as they are sometimes called, every effort has been made to construct and install them in as watertight a manner as possible, in order to insure against entrance of water therein and shorting thereby of the engine ignition devices. Notwithstanding the care and attention which have been given this matter, experience has shown that some moisture and water will accumulate in the shields and cause trouble in the ignition system, particularly in connection with the spark plugs.

It has been found that one of the causes for this is forcing of exhaust gases by the engine into the shields through the spark plugs. The spark plugs which are shielded, have been constructed to render them as gastight as possible,

but in some cases they will nevertheless eventually leak, and it is the gases escaping or forced through these leaky spark plugs into the shield that causes a considerable portion of the trouble. Escapement of gas in this manner builds up a pressure thereof in the shield sufficient to break the rubber seal between the well or casing of the shielded spark plug and the flexible shielding conduit for its ignition cable or conductor. Gas thus escapes into the conduit, resulting in the presence of moisture or water therein due to condensaton of water vapor in the gas. Breaking of the aforesaid rubber seal and deterioration or distention of the rubber grommet, usually comprising the same, enables water in the conduit to penetrate therefrom, into the well of the shielded spark plug, along a path through the faulty grommet and between the ignition cable or conductor and the hollow conductor shielding member or elbow that is connected with the flexible conductor shielding conduit and the well of the shielded spark plug. Water in the shielded spark plug well will cause failure of the spark plug.

Accordingly, it is another object of the invention to provide means which, through venting of any gas forced through the shielded spark plugs, will prevent the same from entering the shield and forming moisture or water therein. In this connection, and when the shield is employed on certain types of aircraft engines, it is a further object of the invention to construct and mount the gas venting means in a manner, such that in flight of the aircraft, suction will be created in said means to assist the gas venting action thereof.

Gas forced through the spark plugs will, it has been found, upon building up of pressure thereof as above pointed out, also escape through some typ s of spark plug ignition cables or conductors along stranded wires thereof. In doing so, the gas under pressure will expand the insulating material of the conductors and cause failure through deterioration and puncture. Accordingly, it is another object of the invention to provide means for venting from shielded spark plugs gases forced therethrough, to thus prevent deterioration and failure of such ignition cables or conductors in the manner aforesaid.

Further to the above, moisture can enter a radio shield through leaks therein developed during service operations and resulting, for example, from abrasion of the flexible metallic shielding conduits. Thus, in rainy weather moisture may enter a leaky shield and cause an accumulation of water therein. Also, air entering a leaky shield by changes in altitude and heating and cooling of the engine will condense and form moisture or water in the shield.

Accumulation of water in the conduits through entrance of moisture causes ignition trouble, and it has been found that such moisture will, through porosity of lacquer covered ignition cables or conductors, enter the shielded spark plug wells by a capillary path between the lacquer covering and insulation of some types of ignition cables or conductors and by capillary attraction of the cotton braiding of other types. Moisture penetration from the conduits to the spark plug wells in this manner is greatly aided by the partial vacuum created in said wells as the engine cools when stopped after running. Another aid to this moisture penetration is the creation of vapor pressure within a moisture containing conduit through absorption thereby of heat radiated from a dead or stopped hot engine.

Accordingly, it is another object of the invention to provide valve means for draining from the radio shield, and particularly from the flexible conductor shielding conduits thereof, any water accumulating therein from any cause, so

as to thus eliminate penetration of moisture or water into the spark plug wells and thereby prevent interference with functioning of the spark plugs and engine. In this connection, it is a further object of the invention to provide such valve means in a form enabling operation thereof by a pressure differential between the outside and inside of the shielding conduit or, when the shield is employed upon some types of aircraft engines, by suction incident to flight of the aircraft.

In some types of radio shields, detachable connections are provided for the spark plug ignition cables or conductors with the leads or conductors in the manifold of the shield, in order to facilitate repairs to, or replacement of, the shielding conduits or the conductors. These connections, or disconnects" as they are sometimes called, provide contacts between the conductors in the manifold and the conductors in the conduits. If there is moisture or water in the shield, and Darticularly in the conduits, the same will reach the spark plugs, or accumulate about the aforesaid contacts, and interfere with functioning of the spark plugs and engine.

Accordingly, it is another object of the invention to provide valve means for draining from the radio shield and particularly from the conduits, any moisture accumulating therein, so as to prevent the same from reaching the spark plugs or the contacts of the aforesaid disconnects and interfering with functioning of the spark plugs and engine. A further object of the invention is to provide an improved and more efficient detachable connection or disconnect for use on radio shields.

It has also been found that abrasion of the flexible conductor shielding conduits of radio shields and resulting entrance and collection of moisture or water therein is in many instances, due to vibration incident to service operations and attending wear on the conduits by the clamps which serve as electrical bonds or grounds between the shielding conduits and the engine and support the conduits on stationary parts of the engine, at points between the connections for the conduits with the manifold and the spark plugs. Accordingly, it is another object of the invention to provide, for a flexible conductor shielding conduit, a bonding clamp so constructed that wear on the conduit and accumulation of water therein as a result thereof will be eliminated.

The invention consists of the construction, combination and arrangement of parts, as herein illustrated, described and claimed.

In the accompanying drawings, forming part hereof, are illustrated two forms of embodiments of the invention, in which drawings similar reference characters designate corresponding parts, and in which:

Figure 1 is a perspective view of one form of embodiment of the invention in which detachable connections or disconnects for the spark plug ignition cables or conductors are employed;

Figure 2 is an enlarged fragmentary front elevational view, partly in section, of another form of embodiment of the invention in which no detachable connections or disconnects for the spark plug ignition cables or conductors are employed;

Figure 3 is an enlarged longitudinal sectional view, partly in elevation, of the upper disconnect, flexible conductor shielding conduit and shielded spark plug shown in Figure 1;

Figure 4 is a vertical longitudinal sectional view, of a conductor shielding conduit bonding and supporting clamp embodying the invention;

Figure 5 is a horizontal sectional view on the line 5-5 of Figure 4, looking in the direction indicated by the arrows;

Figure 6 is an enlarged vertical sectional view, partly in elevation, of conductor shielding conduit drain or valve means embodying the invention; and,

Figure 7 is an enlarged horizontal sectional view of said conductor shielding conduit drain or valve means.

Referring to the drawings, the numeral H] indicates, broadly, a radio shield comprising a manifold II and associated devices hereinafter described which are employed to shield the various elements of the ignition system of an internal combustion engine (not shown) such, for example as an aircraft engine, and thus prevent electrical emanations from said elements from interfering with operation of radio equipment. While the manifold H is shaped as herein shown for use upon one particular type of engine, such as a radial engine, said manifold may be of any suitable form, shape and construction in accordance with various types and makes of engines the ignition systems of which are to be shielded.

The shield I0 is associated with the engine and installed therewith in the usual manner, and the manifold H of said shield will enclose and shield spark plug ignition cables or conductors I! (Figures 2 and 3) which are connected with a source of electric current (not shown) and lead therefrom into said manifold through conduits I] (Figure 1) and connections I! associated therewith.

The conductors l2 comprise wires l5 having insulation i6 and a lacquer covering 11. Other forms of conductors such, for example, as those covered with cotton braiding, may of course be employed. The manifold H is provided with a number of outlets IB for the conductors l2 and it will be understood that the number of conductors and outlets will vary in accordance with the number of cylinders and spark plugs of the various types ofengines for which the radio shields are made. The outlets l8 secured on the manifold ll over openings therein such as indicated at I! in Figure 3 of the drawings.

In the form of embodiment of the invention illustrated in Figures 1 and 3 of the drawings, the construction of the shielding devices for conductors to the spark plugs of the upper engine cylinders of the radial type engine are identical for each of the same, and the construction of the shielding devices for the conductors to the spark plugs of the lower engine cylinders are identical for each of the samee. Therefore, in Figure l of the drawings there is shown only one upper shielded spark plug and its conductor shielding devices and one lower shielded spark plug and its conductor shielding devices, together with detachable conductor connections or disconnects therefor which will be of identical construction for all the spark plug conductors or ignition cables employed.

The shield spark plugs, indicated broadly at 20, may be of any suitable construction and, as herein shown, each spark plug comprises a threaded metallic shell 2| adapted to be secured in a threaded opening of an engine cylinder, and a metallic well 22 threaded or otherwise secured in the shell 2| and containing the insulated center spark plug electrode (not shown). A nut 23 formed on the well 22 is employed to secure it in the shell 2|. Disposed within the well 22 and connected with said electrode is one of the ignition cables or conductors i2 (Figure 3) that is surrounded by a sleeve 24 of insulating material. Surrounding the sleeve 24 between the same and the well 22 is a somewhat thinner sleeve 25 made of insulating material.

The conductor I2 in the spark plug 20 extends therefrom into a hollow conductor shielding member or elbow 26 having a flange 21 which is seated upon a metal washer 28 which, in turn, is seated upon the adjacent end of the spark plug well 22. A nut 29, positioned upon the elbow 26 and having threaded engagement with the well 22, bears against the flange 21 and serves to secure to said elbow to said well. The hollow conductor shielding member or elbow 26 comprises a connection between the shielded spark plug 20 and a flexible metallic conductor shielding conduit hereinafter described. In accord ance with the present invention, this connection or elbow is provided with means for venting to the atmosphere any gas forced into the connection or elbow through the spark plug and which might otherwise enter said conduit, condense to form water therein, and thus cause ignition trouble. Said gas venting means is preferably constructed as follows.

The elbow 26 is provided with an opening or vent 3D. Communicating with the interior of said elbow through said vent 30 and secured therein in any suitable manner is a small capillary tube 3|. This tube 3i is open to atmosphere and is curved along the elbow 28 exteriorly thereof and secured thereto. The opening 30 and tube 3| serve to vent to atmosphere from the elbow any exhaust gas forced therein through the spark plug 20 by the engine. Upon installation of the shield ill on the engine of an aircraft, the elbow 26 will be positioned so that the delivery end of the tube 3| will be open to atmosphere in a direction such that in flight of the aircraft the flow of air will be past said delivery end. Thus, in flight of the aircraft, a suction effect will be produced in the tube 3i to aid the gas venting action thereof.

Surrounding the conductor i2 in the elbow 26 is a sealing grommet 32 that is seated in an enlarged exteriorly threaded end portion 33 of said elbow. Said conductor extends through the grommet 32 into a flexible metallic conductor shielding conduit which is indicated broadly at i 34. The conduit 34 has secured at one end thereof a ferrule 35 having a flange 36. The conductor l2 in the elbow 26 and the conduit 34 (Figure 3) extends through the ferrule 35, and theflange 36 of said ferrule is seated upon the grommet 32 and the enlarged portion 33 of said elbow. A nut 31 positioned upon the ferrule 35 against its flange 36 and having threaded engagement with the threaded end portion 33 of the elbow 26, serves to secure said elbow to the conduit 34. Heretofore, pressure of gas forced through the spark plug into the conductor shielding connection or elbow 26 would build up to an extent sufiicient to force its way through the grommet 32 into the conduit 34 where water vapor in the gas would condense and eventually travel back to the spark plug with resulting ignition trouble therein. By the present invention, however, and through the provision of gas venting means for the connection or elbow 26, this trouble is eliminated.

The conduit 34 is of well known construction and, with its connections with the spark plug 24 and the manifold II, is formed to provide a watertight conductor shielding device. However, in addition to accumulation of water in the conduit heretofore caused by escape of gas into the same, water will under other circumstances, such as previously mentioned, sometimesaccumulate in the conduit with resulting ignition trouble. In accordance with the present invention means are provided to drain from the shield, and particularly from the shielding conduits thereof, any moisture or water accumulating therein in any manner, and said means are preferably constructed as follows.

The conduit 34, which comprises the usual spirally formed flexible metallic tube 36 and woven metallic outer covering 39 therefor, has secured to one end thereof a ferrule 40 having a flange 4|. Formed in the ferrule 46 and in communication therethrough with the interior of the tube 36 are one or more apertures 42. As herein shown, four apertures 42 are provided in the ferrule 40 at equally spaced distances about the same. Positioned on the ferrule 40 exteriorly thereof and over the apertures 42 is a valve in the form of an elastic sleeve 43 of rubber or other suitable material. The conductor I2 in the conduit 34 extends through a seal comprised by a grommet 44 having a shank 45 extending in the ferrule 40 and provided with a beveled end 46 extending to a point slightly below the apertures 42 of said ferrule. The ferrule 40 and the shank 45 of the grommet 44 thus form a trap for any water accumulating in the conduit 34.

Upon a differential of pressure between the outside and inside of the conduit 34 such that the pressure within the same is greater, the valve or sleeve 43 will expand and open at the bottom thereof as shown in Figure 6 of the drawings. Any water in the conduit will thus pass out of the same through the apertures 42. The aforesaid differential will result from changes of altitude of aircraft or from other circumstances. It may, for example, result from increase of pressure in the conduit above outside pressure, due to radiation of heat to the conduit from a stopped, hot engine.

The valve or sleeve 43 will also open as shown in Figure 7 of the drawings by suction effect on the valve produced during flight of aircraft. This suction effect is indicated by the arrows in Figure 7 of the drawings, and opening of the valve as shown therein will enable any water in the conduit 34 to drain therefrom through one or more of the apertures 42 located in the suction area. In this case, the front aperture of the valve which remains closed thereby, is faced toward the direction of flight of the aircraft when the conduit is installed, thus enabling production of the suction opening effect on the valve through flight of the aircraft.

With a radio shield for a radial engine and having detachable conductor connections or disconnects such as hereinafter described and shown in Figures 1 and 3 of the drawings, the ferrule 40 and valve or sleeve 43 will, for the shielding conduits to the spark plugs of each upper engine cylinder, be applied on the lower extremity of the conduit or the end thereof nearest the disconnect and manifold. As respects the shielding conduits to the spark plugs of the lower engine cylinders, the ferrule and valve will be applied to each conduit on the lower extremity thereof or end nearest the elbow 26 and the spark plug 20. This is for the purpose of providing proper drainage of the conduits and to insure that no water accumulating therein will reach the spark plugs or the contacts of the disconnects.

In the form of embodiment of the invention shown in Figure 2 of the drawings, and in which no detachable conductor connections or disconnects are employed. the valve means may be dispensed with as respects the conduits to the spark plugs of the upper engine cylinders. In this case, water in the upper shielding conduits may drain into the manifold and water in the manifold may drain therefrom into the lower shielding conduits. As respects the lower shielding conduits which lead to the spark plugs of the lower engine cylinders. the described valve means will, in the form of embodiment shown in Figure 2, be applied on each cond-ult at the lower extremity thereof or end nearest the elbow 2| and the spark plug to provide proper drainage of the conduit and insure that no water accumulating or draining therein will reach the spark plug.

The conductor l2 shown in Figure 2 of the drawings is unbroken and extends f the source of electric current through the ijianifold, the conduit 34, the elbow 26 and into the spark plug well 22 where said conductor is connected with the spark plug in the usual manner. The conduit 34 (Figure 2) has secured to its upper end a ferrule 48 upon which is positioned a nut 49 that has threaded engagement with the adjacent outlet III of the manifold. and serves to secure said conduit thereto. The grommet 44 shown in Figure 2 of the drawings and which is fitted upon the adjacent conductor i1, is seated in the enlarged end portion 33 of the elbow 28 shown in that figure, and positioned on the ferrule 40. and bearing against the ferrule flange 4| is a nut 41 which has screw-threaded engagement with said end portion 33 of said elbow 24 and thus serves to secure the conduit 34 thereto.

Referring again to the form of embodiment of the invention shown in Figures 1 and 3 of the drawings, means are provided for detachably connecting each conductor I! housed in its conduit 34. with a similar conductor housed in the manifold II. The detachable conductor connections or disconnects thus provided enable repairs to or replacement of the conductors or conduits leading from the manifold to the spark plugs to be quickly and economically made.

The disconnects, indicated at 50 and which are interposed between and connected with the conduits 34 and the manifold Ii, each have housed therein one of the grommets 44 (Figures 1, 3 and 6). The conductor I! in the conduit 34, and upon which the grommet 44 is fitted, also has fitted thereon a tubular element Ii made of insulating material, and said conductor is provided with a metal contact or washer 52 having an opening through which the ends of the wires II of the conductor are lead and bent over the contact 82 into engagement therewith. The grommet 44 (Figure 3) is removably seated upon an interior annular ring-like flange 53 secured to or formed integrally with a tubular metallic housing 54 of the disconnect ll.

Fitted upon the shank 4! of the grommet 44 (Figure 3) and seated upon the adjacent end of the housing 44, is a metal washer 54 upon which is seated the flange 4| of the ferrule 40. Positioned upon said ferrule against said flange and having threaded engagement with the housing 44 isanutilwhichservestodetachablyconnect the conduit 34 with said housing.

Thotubularinouiatingoiement ll ilremovably fitted in an elongated tubular member 51 made of insulating material, and said member, in turn, is fitted in the housing 54 and has one end engaged with the flange 53 thereof. The conductor I! in the manifold ll (Figure 3) extends outwardly therefrom through one of the outlets l8, and said conductor has fitted thereon a series of rubber washers 58 which in turn, have fitted thereon a ferrule 59 having a flange 60 that is seated upon the outer end of said outlet. The conductor l2 upon which the washers 58 and the ferrule 68 are fitted (Figure 3) also has fitted thereon a packing washer iii and a tubular element .2 made of insulating material.

The element 62 is removably fitted in the member 51 which, together with the element 52 bears against the washer ii. The conductor l2 upon which the element 52 is fitted. is provided with a metal contact or washer 63 having an opening through which the ends of the wires iii of said conductor are lead and bent over the contact i3 into engagement therewith. The contact 63 has secured thereto a small coil spring 54 V which detachably engages the contact 52 and provides a detachable electric connection between the two conductors I! in the housing 54. The housing 54 is provided with a nut 65 having screw-threaded engagement with the adjacent outlet ii of the manifold ii and serving to detachably connect the disconnect device 50 in its entirety with said manifold.

By loosening the nuts 56, 28 and 31, the conduit 34 (Figure 3), its contained conductor l2, the grommet 44 and the insulating element 5i on said conductor, and the elbow 26 may be disconnected for repairs to or replacements of any or all of said parts. Likewise, and for similar purposes, access may be had to the conductor if in the manifold ll (Figure 3) and to the described parts associated with said conductor;

through disconnection of the housing 54 from said manifold. The entire disconnect 50 provides a shielding device for the ignition cables or conductors therein, as well as means whereby convenient and economical repairs to or replacement of the conductors, conduit, and associated parts may be made.

As pointed out above, leaks in the radio shield can and will sometimes develop from service operations, and this is particularly true in connection with the flexible conductor shielding conduits. It is found that through vibration and methods heretofore employed for supporting the conduit upon the engine, abrasion of the conduits occur, particularly from wear of the conduit grounding supports thereon, thus causing leaks in the conduits with resulting engine ignition trouble. In accordance with the present invention, means are provided to form bonds or grounds between the conduits and the engine and to support the conduits in such manner as to avoid abrasion of the same and resulting leaks therein, and said means are preferably constructed as follows.

Mounted on a stationary part of the engine, as for example, a push rod housing thereof indicated at46in1 'iguresL4and5ofthedra-wingaisa metal clamp '1 having ears 44 provided therein with openings for a bolt 4! which. together with a nut II on said bolt, serves to secure said clamp passing through the openings in the ears I! and serving to secure the clamp Ii to the clamp 61.

Interposed between the clamp H and the conduit 34 and in clamping engagement with the latter, is a soft interliner 13 of general clamp shaped form enabling it, together with the clamp II, to be fitted upon the conduit 34 prior to securing of said clamp and the interliner upon the clamp 61 and the conduit 34, respectively. The interliner 13 may be made of lead or other soft metal and stamped or otherwise suitably shaped into clamp-like form from a single blank oi such metal to provide, in effect, a small one piece clamp having an inner wall 14 and an outer wall 15 spaced therefrom Prior to the stamping or shaping operation, a clamp shaped cushioning element 16 of rubber or other suitable material is positioned upon the interliner blank so that when the blank is stamped or shaped into clamp form. the element I6 will be gripped between the walls I4 and 15 of the interliner and held securely therein. To aid in retaining the cushioning element 16 in the interliner, the blank from which the latter is made may be serrated on its upper and lower edges to provide prongs H on the upper and lower edges of the wall 15. These prongs II are bent inwardly upon the upper and lower edges of the cushioning element 16 into embedded engagement therewith.

The interliner 13, which in use of the clamps 61 and II bears against the conduit 34 in clamping engagement therewith, will prevent abrasion of said conduit by the clamp ll incident to vibration thereof. The cushioning element 16 will absorb vibration and, in the event of relative movement between the soft metal interliner 13 and the conduit 34, the wear will be on the interliner and not on the conduit. Leaks in the conduit due to vibration and wear of the supporting clamp thereon are thus prevented by the interlined and cushioned clamp. If replacement of the cushioned interliner is desirable or necessary, it can be made without having to replace the supporting clamp. as the interliner, in use, is merely gripped in the clamp and upon the conduit and has no positive connection with said clamp.

Having thus fully described the invention, what is claimed as new and desired to be secured by Letters Patent of the United States is:

1. In an internal combustion engine radio shield of the type having a conduit shielding the conductor for a shielded spark plug of the engine, the combination with said conduit and the shielded spark plug, of a conductor shielding connection therebetween vented to deliver outwardly therefrom any gas forced through said spark plug into said connection by the engine and electric means adapted to close the vents in said connection.

2. In an internal combustion engine radio shield of the type having a conduit shielding the conductor for a shielded spark plug of the englue, the combination with said conduit and the shielded spark plug. of a conductor shielding connection therebetween having a tube leading from its interior outwardly to the atmosphere for venting any gas forced through said spark plug into said connection by the engine and yieldable means controlling the passage through said tube.

3. In an internal combustion engine radio shield of the type having a conduit shielding the conductor for a shielded spark plug of the engine, the combination with said conduit and the shielded spark plug, of a conductor shielding connection therebetween comprising a tubular elbow vented to deliver outwardly to the atmosphere any gas forced through said spark plug into said connection by the engine and an elastic sleeve on said elbow preventing an inward flow through the vents therein.

4. In an internal combustion engine radio shield of the type having a conduit shielding the conductor of a shielded spark plug of the engine, the combination with said conduit and the shielded spark plug. of a conductor shielding connection therebetween comprising a hollow elbow having an attenuated delivery tube leading outwardly from the interior thereof to the atmosphere for venting any gas forced through said spark plug into said connection by the engine the vents of said elbow being surrounded by an elastic sleeve preventing inlet therethrough.

5. In a radio shield for installation with an internal combustion engine upon an aircraft and of the type having a conduit shielding the conductor for a shielded spark plug of the engine, the combination with said conduit and the shielded spark plug, of a conductor shielding connection therebetween hav us a tube leading from its interior to the atmosp ere, said connection being adapted for installation in a manner such that in flight of the aircraft flow of air past the delivmy end of the tube will create suction therein and aid in venting to the atmosphere through said tube any gas forced through said spark plug into the connection by the engine. I

6. In a radio shield for installation with an internal combustion engine upon an aircraft and of the type having a conduit shielding th conductor for a shielded spark plug of the engine, the combination with said conduit and the shielded spark plug, of a conductor shielding connection therebetween, said connection comprising a hollow elbow having a tube leading from the interior thereof to atmosphere and curved along and secured to the elbow exteriorly thereof, said elbow being adapted for installation in a manner such that in flight of the aircraft flow of air past the delivery end of the tube will create suction therein and aid in venting to the atmosphere through said tube any gas forced through said spark plug into the connection by the engine.

7. A hollow elbow for shielding the conductor for a shielded spark plug of an internal combussion engine, and connecting a shielding conduit for said conductor with the shielded spark plug, said elbow being vented to deliver to the atmosphere any gases forced by the engine through said spark plug into the elbow and an elastic sleeve normally closing the vents in said elbow.

8. A hollow elbow for shielding the conductor for a shielded spark plug of an internal combustion engine and for connecting a. shielding conduit for said conductor with the shielded spark plug, said elbow having an attenuated tube leading from the interior thereof to atmosphere and being curved in conformity with the elbow exteriorly thereof, said tube serving to deliver to atmosphere any gas forced by the engine through said spark plug and into the elbow during use of the engine and elastic means normally closins the entrance to said tube.

9. A hollow member for shielding the conductor for a shielded spark plug of an internal combustion engine and for connecting a shielding conduit for said conductor with the shielded spark plug. said member having an attenuated tube leading from the interior thereof to the atmosphere, said tube extending along the hollow member exteriorly thereof and serving to deliver to the atmosphere any gas iorced by the engine through said spark plug into the hollow member and means to prevent entrance of air and gas into said tube from its open end.

10. An internal combustion engine radio shield having flexible valve means for draining from the shield any moisture accumulating therein.

11. An internal combustion engine radio shield comprising a conduit for shielding the conductor for a shielded spark plug of the engine. said conduit being provided with flexible valve means for draining from the interior of the conduit any moisture accumulating therein.

12. In an internal combustion engine radio shield comprising a conduit for shielding the conductor tor a shielded spark plug oi the engine, a valve for draining the conduit, said valve comprising an apertured ferrule secured on the conduit, and an elastic sleeve positioned upon said ferrule exteriorly thereof.

13. In an internal combustion engin radio shield of the type having a conduit shielding the conductor for a shielded spark plug of the engine, means for preventing accumulation of moisture in the shield, said means comprising a vented conductor shielding connection between the conduit and said shielded spark plug, a perforate ferrule on said conduit and an elastic sleeve on said ferrule.

14. In a radial internal combustion engine radio shield of the type having a manifold enclosing a conductor and a device adjacent the maniioid for connecting or disconnecting said conductor with a second conductor attachable to a shielded spark plug of an upper cylinder oi said engine. the combination with the device and the shielded spark plug. of a shielding conduit for said second conductor connected with the device and said plug and provide adjacent said device with elastic valve means for draining from the interior of said conduit any moisture accumulating therein.

15. In a radial internal combustion engine radio shield oi the type having a manifold enclosing a conductor and a device adjacent the manifold for connecting or disconnecting said conductor with a second conductor attachable to a shielded spark plug or a lower cylinder of said engine. the combination with the device and the shielded spark plug. a shielding conduit for said seccnd conductor connected with the device and the plug and provided adjacent the plug with elastic valve means for draining from the interior oi said conduit any moisture accumulating therein.

16: In an internal combustion engine radio shield of the type comprising a manifold having a conductor therein leading through an outlet thereof and a conduit having a conductor therein for connection with a spark plug. means for detachably connecting the conduit and conductors, said means also shielding the conductors, said means comprising a metallic housin provided with a tubular insulatin member adapted to removably n-t upon the conductors and maintain them in opposed endwise relation therein, contacts on said conductors for detachably connecting them in said member, couplings for detachably connecting said housing with said manifold and said conduit, a stationary rod adiacently parallel to said conduit, a cushioned clamp connecting therebetween and valved means for the egress of liquid from said conduit at a "in for connection with a spark plug, means for detachably connecting the conduit and conductors. said means also shielding the conductors. said means comprising a metallic housing provided interiorly theme! with a tubular insulatin member, tubular insulating elements on opposed ends of the conductors adapted to be removably fitted therewith in opposed endwise relation in the insulating member of said housing, electrical contacts on the opposed ends oi the conductors detachably connecting the same in said member, couplings for detachably connecting the housing with said manifold and said conduit, a stationary rod adjacently parallel to said conduit, a cushioned clamp connecting therebetween and valved means for the egress oi liquid from said conduit at a point adiacent the spark plug.

18. In an internal combustion engine radio shield of the type comprising a manifold having a conductor therein leading through an outlet thereof and a conduit having a conductor therein for connection with a spark plug, means for detachably connecting the conduit and conductors, said means also shielding the conductors, said means comprising a metallic housing provided interiorly thereof with a tubular insulatin member, tubular insulating elements on opposed ends of the conductors adapted to be removably fitted therewith in opposed endwise relation in the insulating member of said housing. contacts on the opposed ends of the conductors for electrically and detachably connecting the same in said member, said contacts comprising washers on said ends oi the conductors. one 0! said washers having a coil spring secured therein for contact with the other washer, couplings for detachably connecting the housing with said manii'old and said conduit and non-abrasive means to support said conduit.

19. In an internal combustion engine radio shield oi the type having a flexible metallic shielding conduit for a conductor to a spark plug of the engine, the combination with the conduit and a stationary part 0! the engine, of a pair 0! split clamp bands each having radially extending spaced ends adapted tor inent, one or said bands engaging said engine part and the other with the conduit. a single clamping means for all of said band ends, an interliner tor the second named band, said interliner-having spaced concentric end walls. cushions disposed between said walls, and inreaching mouse on the edges oi said end walls to retain the cushions therebetween.

WARD D. DAYTON.

CERTIFICATE OF C0 ERECTION Patent No. 2,516,50h. fiaril 15, 191

. WARD D. DAYTON.

It is hereby certified that error appears in the printed speqification of the above numbered patent requiring correction as follows: Page 5, first column, line 57, claim 1, for "electric" read "elastic"; and that the said Letters Patent should be read with this correction therein that the same may conform to the record of the case in the Patent Office.

Signed and.sealed this 29th day of June, A. n. 1915 Henry Van Arsdale,

(Seal) Acting Commissioner of Patents.