US2361699A - Ignition circuits - Google Patents

Description

Oct. 3l, 1944. 1 MALCZEWsKl 2,361,699

IGNITION CIRCUIT Filed Sept. 26, 1941 QLMJQMM Patented Oct. 31, 1944 IGNITION CIRCUITS .lei-emi Maimwski, Lyon, France; vested in the lAlien Property Custodian Application September 26, 1941, Serial No. 412,527

In France February 5, 1940 A 3 Claims.

The present invention relates to electric circuits of the armoured ignition type for engines (and especially aircraft engines), including high voltage connectors adapted to establish connection between two plugs or pins carried by respective elements of the circuit, these elements consisting, for example, of the central electrode of a spark plug and the conductor through which current is fed to said spark plug.

It is known that, in high voltage connectors of this kind, the pin which is in line with the central electrode of the spark plug must be made of suitable length so as to constitute a safety guard or protection and to prevent the possibility of sparks between the ground (metallic frame) and the contact plate carried by the end of the pin.

For high altitude flight, that is to say flight in a rareiied atmosphere, it is necessary to increase this safety guard or protection, which corresponds to increasing the length of this pin. However, in the existing constructions, this increase of length would involve the construction of a connector of prohibitive size, especially when the pin of the leading-in conductor is in line with that of the electrode.

The object of the present invention is to provide a connector of the type above described which avoids the above mentioned drawbacks and, in particular, in which the protection is increased, by increasing the length of the pin in question, without increasing the overall length of said connector.

According to an essential feature of the present invention, the connector is made in such manner that the two pins between which an electric contact is to be ensured are juxtaposed over at least a portion of their length.

Other features of the present invention will become more apparent from the following detailed description of some specific embodiment thereof.

Preferred embodiments f the present invention will be hereinafter described, with reference to the accompanying drawing, which are given merely by way of example, and in which:

Fig. 1 is an axial sectional view, partly in elevation, of a portion of an armoured ignition Fig.- 2 is a side view corresponding to Fig. 1;

Fig. 3 is a sectional view on the line H I-III of Fig. 1;

Fig. 4 is a view similar to Fig. 1, corresponding to another embodiment of the invention;

Fig. 5 is a side elevational view of the device of Fig. 4. v

I will now proceed to describe the structures disclosed by the drawing, which relate tospark plug connectors for airplane engines intended to work at high altitudes.

The general arrangement is such that the metallic contact to be provided between the pin of the central electrode and the pin of the leading-in conductor is located as far as possible from the metallic body of the spark plug, without involving a substantial increase. of the overall length of the device as compared with that of the usual constructions.

In order to accomplish this purpose, according to a feature of the invention, the pins are mounted insuch manner as to be juxtaposed over at least a portion of their length.

More specifically and according to one advantageous embodiment of the invention, the parts are arranged in such manner that the portion of the circuit constituted by the two pins has an hair pin shape, with the branches of the hair pin corresponding to the pins, the electric connection between them being obtained through contact plates or other suitable means located on the end thereof which is most remote from the metallic body of the spark plug.

These general features may be embodied in the followingA construction given by way of example:

The spark plug may be made in any desired known manner, but is provided with a central electrode which is of a greater length than is customary, so as to form the pin 2, which is in turn provided at its end with a contact plate 3. This pin, which is preferably of rectilinear shape, is provided with the usual outer insulating sheath, 50 mms. or more in length.

, Referring now to the lead-in conductor l, it will be seen from the drawing that the conductor is insulated as usual by means of an insulating sheath 5 and is armoured by the usual means as shown at 6. The pin terminates in another pin having a length corresponding to that of the pin 2, and includes a rigid insulating sleeve l, as shown in Figs. 1 to 3 (and which may consist of mica or the like). This second mentioned pin is provided, at its end, with a contact plate 8, suitably mounted for ensuring pins are engaged with each other.

The means employed' in order to secure the asoneoe electric contee: with plate a. when both of the pins in juxtaposed position for at least a portion of their length comprise abox adapted to ensure the guiding f the pins and to complete the insulation while ensuring the continuity of thev 'rne contact between the pins is located es rer as possible from the spark plug body, which ensures the maximum protection against the forniation of sparlm;

The space occupied by the device is as reduced VThe construction is extremely simple, the capshaped insulating portion being easy to remove I will describe two preferred embodiments as illustrated by the drawing. l In the embodiment shown in Figs. 1 to 3, the system includes the following elements:

a. A metallic shell 9, mounted in a removable manner on the body of the spark plug, as for' example by means of a nut I0 adapted to apply against the body a flange such as I01, the shell is also provided with an aperture il through which the lead-in conductor is introduced, making a bend of substantially 90 with respect to the longitudinal axis of the plug for instance;

b. Insulatlng means, in the form of a cap l2, ofr

moulded or other insulating substance, adapted to cover both of said pins 2 and l, said cap beingsubstantially rectangular in shape, bearing at its base against the edge I3 of shell 9, and advantageously including two longitudinal grooves. ld for the guiding of the pins; and

c. A metallic cover I5 adapted to surround the whole and xed thereon in any suitable manner, for instance, by screwing or by welding;

In the embodiment of Figs. l to 3, this cover l5 A linear;

is supposed to be xed by screwing, which can be facilitated by the presence of conical portions such as IB, and also by the provision of a spring clip il, which is pivoted at i8.

- from its mold, without tear or breaking it;

The cooling of the central electrode of the spark lplug is facilitated, owing to the increase of its length: and I The lead-in conductor can be brought substantially to the level of the body ol the spark plug, y

thereby obtaining a further reduction in the space occupied by the entire ignition circuit.

It should be noted that at least one of the pins might be of curved shape instead of being recti- Furthermore, the contact between the two pins might be ensured in any suitable manner different from that described, and there may be any number of pins, in addition to those shown.

In a general manner, while I have, in the above description, disclosed what I deem to be practical and elcient embodiments of the present invention, it should be well understood that I do not wish to be limited thereto as changes may be made in the arrangement, disposition and form of the parts without departing from the principle of the present invention as comprehended within the scope of the appended claims.

What I claim is:

1. An electricalconnectlng unit comprising an insulating sheath and a plurality of insulated conducting core pins, means on the interior of said in juxtaposed position with respect to each other 'I'he electric contact is established between/ 'plates 3 and 8 through a spring I9 or in any other suitable manner.

In the embodiment of Figs. 4 and 5, the portions 9 and I5 of the above mentioned embodiment are combined into a single piece, preferably consisting of two halves I9, stamped and welded together along lips 20.

In order to permit the easy removal of the pin 1, the latter may constitute an extension of exible conduit 5.

In this concept of my invention, I provide in the bottom of insulating cap I2, a contact piece 2| which serves to connect contact plates 3 and 8 together, with springs I9 interposed therebetween. This cap may also be provided with guiding grooves I4, and even cylindrical recesses, corresponding to the diameter of the pins.

Furthermore, in order to prevent the exible pin l from escaping, provision is made at the inlet of aperture Il of a tightening device which comprises a screw-threaded piece 22 rigid` with the aperture, a iiexible ring 23, a pressure ring 24 and,

for at least a portion of their length, resilient means in one end of said sheath electrically inter. connecting the core of at least one of said pins with the other cores of said pins, a lead-in wire, means on the other end of said sheath permitting said lead-in wire to be connected with one of said conducting cores at an angle of apprommately with respecty to the longitudinal axis of said sheath, and a metal covering surrounding said sheath.

2. An electrical connecting unit as deiined in claim 1, said lead-in wire being armoured and external means cooperating with said metal sheath connecting said armoured lead-in wire therewith.

3. An electrical connecting unit comprising a spark plug having an elongated central electrode. means securing a bifurcated metallic supporting structure on the top of said plug, an insulating cap having a metallic exterior cover and being adapted to be removably'secured on said supporting structure, means in the interior of said cap adapted to support said central electrode and an insulated conducting core pin in juxtaposed position with respect to each other, resilient means in one end of said cap adapted to electrically lnterconnect said central elect'rode and said pin, one arm of said bifurcated supporting structure extending outwardly from the longitudinal axis of said plug at an angle of substantially 90, and a lead-inwire extending within said arm and being electrically connected with the core of said pin.

JRm MALczEwsm.

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