US1999118A - Shielding system for radioreceiver equipped vehicles - Google Patents

Description

A, sv. slMsAcK SHIELDING SYSTEM FOR RADIORECEIVER EQUIPPED VEHICLES Filed Aug, so, 1954 prl 23, 1935.

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N|/////////A/J\,.&Ww mllllhmlllllllm @w1 Patented Apr. 23, 1935 PATENT OFI-ica SHIELDING `SYSTEM FOR BADIORECEIVEE EQUIPPED VEHICLES Anton S. Simsack, Philadelphia, a. Application August so, 1934, serial No. '142,161

5 Claims.

This invention relates to shielding systems for ignition elements oi' radio-receiver-equipped vehicles, the general object being to providean improved system which functions to eliminate vthe disturbing eirects'which certain of the 1gnition elements have on a radio receiver. The invention is applicable to automobiles, aeroplanes, motor Aboats'and other vehicles employing ignition systems.

An object of the` invention is to provide a system comprising shielding devices for the essen- `tial ignition elements, which devices are simple in construction and may be readily applied to the ignition elements.

Another object of the invention is to provide a novel shielding andvconductor attachment structure for each of the ignition elements.`

A further object .of the invention is to prpvide a shielding device for an ignition element comprising a cap which is adapted `ior removable attachment to the ignition element without the necessityv oi attaching devices.

A still further object of the invention is tov provide a shielding device for a spark plug comprising a plurality of telescopic,l members which are adapted to cooperate with each other and with certain other elements to attain the desired ments being shown partly in section to illustrate the details;

Fig. 2 is an enlarged section of one of the shielding devices; w

Fig. 3 is an enlargedA sectional view of another of theshielding devices; and

Fig. 4 is a perspective ,view of one of the shielding elements.

Referring to Fig. l of the drawing, there is shown the usual induction coil I, distributor 2. and spark plug 3 commonly found in the ignition system of a vehicle whichA is propelled by an internal combustion engine. The complete ignition systemcomprisesother elements but the disturbance effect upon a radio receiver` carried by a vehicle or in'the vicinity 'thereof is due wall of the cup-shaped member.

(Cl. 12a-14.8)

duction coil, are of such character that they have practically no disturbing eii'ect on the radio receiver. 'I'he characteristics of the voltages and currents beyond the induction coil, however, are l such as 'to set up disturbances, principally by 5' radiation of disturbing energy. It is for this reason that the present invention is directed to these disturbing elementsoi! the ignition system.

The induction coil I `is generally of conventional form and is modied only at the top pori tion thereof in accordance with the present invention. As is customary, the top portion of this element, to w ich the highv tension conductor 4 is attached, omprises a recessed conical inl sulating body 5. Asfshowny more clearly in Fig.A 2, I5 there is seated within the recess 6 of the said body a metallic cup-shaped member 1k which is adapted to receive the end'of conductor 4.

.The stranded conductive core of the insulated 1 thatthe resilient fingers of the terminal member make good electrical contact with the inner An insulating sleeve or bushing I0 extends slightly into the cup-shaped member 1 and engages the resilient fingers of the terminal member 8. Conductor I has an outer metallic sheath Il,

the end of which is flared outward, as at I2, and

is securely held between the upper end of sleeve I0 and the annular wall of the truncated conical member I3. The conductor extends through the apertured wall of member I3 as illustrated. This member is preferably formed of sheet metal and `is slit longitudinally at I4 (see. Fig. 4) to impart resiliency or expansibility to it. A'n insulating sleeve or bushing I5, which may be formed oi rubber or other suitable material is positioned within member I3., as clearly illustrated. The cap-like device comprising members I3 and I5 is of such shape and dimension that it ts snugly and resiliently upon the conical body 5, as illustrated in Fig. 2. The inner surface of member I5 frictionally engages the outer surface of body 5, holding the device securely in place.

It will be seen that the e1ettrica11y conductive member I3 forms a shield about the upper part of body 5 and the conductive elements therein, so as to effectively prevent radiation of disturbing energy at that point. It is at that point that the disturbing energy would be radiated in the absence of the shielding device because the thickness oi the insulation is diminishing to a minimum and the disturbing energy naturally seeks the path of least resistance. The shielding member i3 is electrically connected to the conductor sheath ll, which, in turn, is grounded in any suitable fashion as indicated at i6. Thus, there is provided a goed electrical path from the shielding element to ground, through which path the energy which would otherwise be radiated, is conducted, thus preventing interference with the radio receiver.

Mechanically, the shielding andconductor attmbment structure is strong and there is little possibility of the parts becoming detached.v it naturally toilows that the electrical connections which rely upon the mechanical parts cannot become loose. The irictional engagement of the terminal 8 with the inner wall of member 1 secures and maintains the end of the conductor in place. Added to this is the clamping of the conductor sheath between the sleeve i@ and member which also insures hrm connection of` the conductor. The frictional engagement oi member with the outer surface of body 5 is, of course, important to the proper :functioning of the device and serves further to maintain the parts in proper position. It will be understood, however, that the parts may be modified as to the details. For example, the cap-like shielding device may be arranged ior threaded attachment to the body It will be seen that this device is simple and autoreis ready connection of the conductor to the induction coil. In connecting the conductor, it is simply necessary to slip the cap-like device over the conductor, then cut back the metallic sheathing to the proper point, after which the sleeve lil may be placed over the exposed insulation and the terminal 8 may be conventionally applied. The end oi the conductor may then be inserted in recess '5 and thecap lowered into place.

The distributor 2 is also of conventional construction excepting for the top portion comprising the conductor attachment portions I8. Each oi these portions is generally similar to the structure employed at the upper part of the induction coil, as above described. The above description, therefore, applies to each of the conical conductor attachment portions of the distributor. 'I'he shielded conductor 4 and the shielded spark plug conductors l1 are'thus effectively connected to the distributor and, at the same time, there is provided about each conductor attachment portion a shielding device which is connected electricalli7 to the conductor sheath.

Each oi the spark plugs 3 may take the form illustrated. As customary, each plug comprises a metallic shell i8 having a lower threaded portion 28 which is adapted for removable attachment to the cylinder head 2l of the internal combustion engine. As usual, the grounded shell i8 carries the outer electrode 22, while the central glectrode 23 extends through insulating member As shown more clearly in Fig. 3, the insulating member 24 extends considerably above the uppermost part of shell i9 and the central electrode terminates at its upper end in the projecting threaded portion 25. In accordance with the present invention, a recessed electrically-conductive member 26 is adapted for threaded attachment to the portion 25 and is also adapted t0 receive the end of conductor I1 in .its recessed portion. It will be seen that member 26 corresponds to the cup-shaped member 1 of the previouslydescribed device and cooperates with its associated elements in substantially the same manner as does member 1. An insulating sleeve 21, corresponding to the sleeve 10, extends slightly into vthe recess of member 26 and engages the terminal member or clip carried at the end of conductor l1.

The upper end of sleeve 21 extends into a recessed nut or cap 28 and cooperates therewith to secure the ared end of the conductor sheath, as at 29. The end of the metallic sheath is securely held between the upper end of sleeve 21 and the annular shoulder 30 of cap 28.

The cap extends into and is threadedly attached `to a metallic sleeve 3i which is of substantial length as shown. Within this sleeve, there is positioned an insulating sleeve or bushing 32. Member 26 ts snugly within sleeve 32 and is attached thereto in any suitable manner. This attachment may be effected simply by rictional tight iit of the parts or by adhesion or by positively locking the parts together. The metallic sleeve 3i is provided with an annular rib 33 which acts as a stop or abutment for the outer metallic sleeve 34 and the interposed helical spring 35. Sleeve 3l! is telescopically related to sleeve 3 i, these two members being adapted for movement relative to one another. The upper end of sleeve 34 is turned inwardly as at 35 in order that it may abut against the annular ribV 33 and limit the extended position oi the telescopic members. The lower end of the sleeve 34 is also turned inwardly as at 31 and is adapted to retain the helical spring 35 and to electrically engage the grounded shell i9 of the spark plug. The helical spring is maintained in position between rib 33 and the lower inwardlyturned end 31 of sleeve 34. The function of this spring is to urge the telescopic members into extended position and thus maintain the device in adjusted position upon a spark plug.

By virtue of the telescopic construction o! this cap-like device, it may be used on spark plugs of varying sizes and it is self-adjusting when applied to a plug so that it adapts itself properly thereto. The telescopic conductive sleeves 3| and 36 constitute a complete shield about the -upper part of the plug, which shield is grounded by engagement with the grounded shell I9 of the spark plug. The conductor sheath is electrically connected to the grounded shielding elements through the metallic nut or cap 28. Thus, the portion of the spark plug which is prone to radiate disturbance energy is completely shielded, as is also the conductor leading to the plug. The path to ground offered by the shielding elements effectively prevents the radiation ol. disturbance energy. The conductive member 28 may be formed oi.' a metallic alloy having relatively high ohmic resistance. Ihis places a high impedance in the ignition circuit through the spark plug electrodes and causes the disturbance energy generated by the ignition system to more readily' take the shielding path to ground.

The structure is strong mechanically and is characterized by tight mechanical and electrical joints throughout. Furthermore, the structure is simple and enables ready attachment of the conductor to the plug. In applying thev device, it is simply necessary to place the cap 28 upon the conductor, after which the terminal clip may be applied. 'Ihe metallic member 26, together with the telescopic sleeves are assembled on the plug in the obvious manner. The conductor is then causes the disturbances,v It will be seen that the shielding system comprises simple devices which may be readily applied to the ignition elements and which are connected to ground by good electrical and mechanical joints. It will be unl derstood that the invention is'not limited to the specific preferred form disclosed herein but is capable of various modications and changes. The various conductive and linsulating parts of thesystem may be formed of anysuitable materialvwhere a particula llaterii'tl has not been specified or designatedv preferable,v

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" 1, Inl a shielding shielding 'd'evicev comprising f a plurality fof tele'- scoplc members adapted for `adjustableposition-l l l r n tionjof theplugand` theaforesaid elements, one'r gagea grounded portion ofthe plug; the other of y saidgtelescopic.members being vadapted to removablyrecei've said cap, :and means lurging said tele- :scopic members into eirtendedpos-ition.A

ing upon an ignition-element. I

ments v of f a.v .radio`f.zreceiverequippedfy vehicle",

scopic member inguponanigxiil n l y ,y

said members into xten'dedpositipn- 3. In aA shieldingfsystem sistemi@ ther ignition" 'ele-- ments ofvr varadio receiver-equippedvehicleya yments of a. `radio receiver-equipped vehicle. a.

shielding device comprising a plurality of telescopic members adapted for adjustable positioning upon an ignition element, and a helical spring interposed between said members and urging them into extended position.

4. In a shielding system for the ignition elements of a radio receiver-equipped vehicle, a shielding device for a spark plug comprising a pair of telescopic members adapted to surround an ungrounded conductive portion of the plug, one of said members being adapted to electrically engage a grounded conductive portion of the plug, and means for urging said member into good electrical contact with said grounded portion of the plug.

5. A shielding and conductor attachment dea conductor, an linsulating sleeve seated in said recess and surrounding said conductor, .an ap-v {ertured recessed 'cap surrounding said conductor and seating an end of said sleeve, a; pair of telescopic conductive members surroundingl a por- ANTON s." SI'MSACK.

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