US2131937A - Insulating cover - Google Patents

Description

Oct. 4, 1938. R. DEwAR ET AL INSULAT ING COVER Filed May 17, 1954 ATTORNEYS.

Patented Oct. 4, 1938 PATENT OFFICE INSULATING COVER Robert Dewar and William T. Sanford,

I-Ioosick Falls, N. Y.

Application May 17,

3 Claims.

This invention relates to insulated covers or caps, and especially to insulated covers or caps for the distributors or coils which are employed in the ignition systems of internal combustion engines. As heretofore constructed, such covers or caps were made from a material, such as Bakelite, having a high insulating value, and they were provided with a centrally disposed housing member adapted to receive a conductor which led from the spark coil to the rotor element of the distributor and with a plurality of peripherally disposed housing members adapted to receive conductors which led from the contact elements of the distributor to the spark plugs of the system.

In many instances, however, it is desirable to adjust the intensity of the spark toobtain maximum eficiency, and for this reason it is now common practice to employ auxiliary spark intensifying devices between the distributor and the spark plugs. This arrangement however, is unsatisfactory due principally to the fact that the auxiliary unit frequently becomes disconnected from the system, thereby causing open circuits.

In accordance with the present invention, however, the above objection obviated by incorporating adjustable spark intensifying devices in the housing members of the cap or cover of the distributor.

For a clear understanding of the invention reference may be had to the accompanying drawing. In the drawing, the invention is shown merely in preferred form and by way of example but obviously many variations and modifications may be made therein which will still be comprised within C its spirit. It is to be understood, therefore, that the invention is not limited to any specific form or embodiment except in so far as such limitations are specified in the appended claims.

Referring to the drawing:

Figure l is an elevational view in section showing one embodiment of the invention;

Figure 2 is an elevational View in section showing another embodiment of the invention; and

Figure 3 is an enlarged view in detail of the adjustable unit employed in the present invention.

Figure 4 is a detail cross section of the intensifying device mounted in the housing.

As shown, the cover comprises a cup-shaped member I from the central portion of which a housing member I I opens outwardly and from the periphery of which a plurality of similar housing members I2 open outwardly in spaced relation. The number of peripherally disposed housing members correspond to the number of spark plugs in the system. The cover or cup-shaped 1934, Serial No. 726,060

member I0 and the housing members are desirably moulded as a unit and from a substance or compound having a dielectric strength of at least 300 Volts per milliampere to prevent failure of the device after it has been in use. A metallic terminal I3 is positioned in the lower end of each of the housing members, the lower end of the terminal positioned in the centrally disposed housing member I I being provided with a carbon contact button I4 through which contact is constantly made with the usual rotor arm (not shown) and the lower ends of the terminals positioned in the peripherally disposed housing members being extended downwardly to form exposed terminals I5 through which contact is made with the rotor arm as it rotates. The method of establishing electrical communication through the distributor cap is well known and detailed description thereof is not deemed necessary.

In one embodiment of the invention, as shown in Fig. l, the upper ends or contacting surfaces I6 cf the terminals I3 in the housing members is in contact with the moulding compound or substance but this is desirable only when the compound or substance has an exceedingly high break down strength as for example, a break down strength greater than 300 volts per milliampere since under such conditions there is substantially no current leakage from the terminal through the compound or substance.

In another embodiment of the invention, as Shown in Fig. 2, the central portion of the upper ends of the terminals I3 in the housing members form projecting studs I'I so as to provide an air space between the upper ends or contacting faces I6 and the moulding compound or substance.

The upper end of each of the housing members is provided with means whereby an adjustable spark intensifying device may be assembled therein, and to this end the upper end of each of the housing members is provided with screw threads I8. As shown more clearly .in Fig. 3, the spark intensifying device desirably employed comprises a tubular member 2B adapted to receive the end of an insulated conductor (not shown) and the lower end of which is closed to form a contacting face 2|. The outer upper surface of the tubular member is provided with screw threads 22 adapted to engage the screw threads I8 in the housing members so that the position of the device may be varied in the housing members to vary the spark intensifying properties of the device.

Having thus described our invention, we claim:

l. In combination, an insulating cover comprising a cup-shaped member having a housing mem- 3. In combination, an insulating cover comprising a cup-shaped member having an internally threaded housing member extending outwardly therefrom, and a spark intensifying device positioned in said housing member, said device comprising a tubular member having its upper end open and in threaded engagement with said housing member and its lower end closed and out of contact with said housing member.

ROBERT DEWAR. WILLIAM T. SANFORD.

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