US2081502A - Ignition apparatus - Google Patents

Description

May 25, I937. E. B. NOWOSIELSKI IGNITION APPARATUS Filed Nov. 5, 1935 INVENTOR. Edward B. /Vowos//sA/' TOR Patented May 25, 1937 PATENT OFFICE IGNITION APPARATUS Edward B. Nowosielski, Bloomfield, N. J., assignor to Eclipse Aviation Corporation, East Orange,

N. J., a corporation of New Jersey .Application November 5, 1935, Serial No. 48,415

3 Claims.- (Cl. 123-169) The present invention relates to ignition apparatus for internal combustion engines, and more particularly to spark plugs.

One of the objects of the present invention 5 is to provide novel means for thermally and,

electrically shielding spark plugs in order to avoid injury thereto by excessive heat accumulation at vulnerable points, and to prevent electrical interference with sensitive electrical equipment in' the vicinity, such as radio receiving apparatus.

Another object is to provide a novel spark plug shield which is light in weight, simple in construction and inexpensive to manufacture.

A further object is to provide a metallic shield for a spark plug which may be readily and easily assembled or disassembled, and which is adapted for use with any of the usual types of spark plugs.

Still another object is to p'rovide a spark'plug shield in which the proper clearance between its metallic parts and the.high tension terminal of the spark plug is maintained by the provision of novel insulating and heat resisting supporting means which also provides a support for the ignition cable which is connected to the hightension terminal.

A still further object is to provide a novel shield for spark plugs which is both mechanically rugged and electrically efflcient for shielding purposes, and yet requires only a minimum of shielding and insulating material.

These and other objects of the invention will become apparent from inspection of the follow- 3 ing specification when read with reference to the accompanying drawing wherein is illustrated the preferred embodiment of the invention. It is to be expressly understood, however; that the drawing is for the purpose of illustration only,

40 and is not designed as a definition of the limits of the invention, reference being had to the appended claims for this purpose.

In the drawing: Fig. l is a longitudinal sectional view of the 45 shield in its preferred form shown in its. prerelation to the spark plug when completely installed and secured in place; and I Fig. 2 is an exploded perspective view of the adjustable means for holding the shield in place. 50 In the form shown, a cup-shaped metallic shielding member 4 constitutes the lower part of the shield, and surrounds andextends substantially the length of a spark plug 5 which is to be shielded. This spark plug my be of any of the 55 usual types and is provided with a high tension terminal 6 to which is connected the positive electrode I. A body portion 8 receives the negative electrode l0, and is adapted for threaded engagement with an orifice in the cylinder wall of an internal combustion engine Shielding member 4 6 is provided with an inturned annular lip or flange II at its lower end which is adapted to flt under flange 8 of the spark plug and to be securely held, between said flange and the outer surface of the engine cylinder wall when the spark plug is 10 threaded therein. Shielding member 4 may also be provided with a plurality of louvres or apertured niches (not shown) circumferentially spaced around its lower portion to ventilate and cool the lower portion of spark plug 5, and also 15 to allow the drainage of any moisture which might formon the shield.

An upper shielding member or cap l3 has an annular base i4 adapted to rest on rim it of the member 4, and a threaded extension l5 to 0 receive the end of a metallic sheath (not shown) enclosing the ignition cable. The top surface I of cap i3 is flattened to receive the base of an adjusting cap 5|, the lower portion of which is knurled as indicated in Fig. 2 at 52, and the 5 upper portion of which is internally threaded as indicated at 53, and radially grooved as indicated at 54 in Fig. 2, the purpose of the threads being to receive the corresponding threaded screw 55, and'the purpose of the radial grooves being 30 to receive the oppositely extending arms of the. locking pin 51, the said arms being also received in the axially extending slot 58 in the screw 56. As shown, the screw 551s counterbored to receive a coiled compression spring 59 and a pressure plate or disc 6| against which one end of the spring bears to exert pressure upon the central portion 62 ofv a wire ball or clamp .63 passing through the slot 58 of the pin 56 and extending downwardly to terminate in inwardly turned ends 64 and 65 pivotally received in openings formed in the downwardly extending skirt 56 of the rim l6 of the lower shield 4. The type of wire bail shown at 5 has, of course, been used heretofore, but in former installations the resiliency of the bail has been relied upon as practically the sole means'of locking the cap in position. In practice it has been found that this is not suflicient, particularly after repeated removals and re-applications of the ball from which manipulation thereof tends to interfere with its initialtemsion, and thereby reduces the eflectiveness of the grip. In the construction above described, I provide means for compensating for such variations in the form of the adjusting elements indicated cap l3.

The present invention also includes a novel form of insulation to be placed between the high tension terminal and the metallic shield, to perform not only its electrical function in an eflicient manner, but also to act as a barrier blocking heat flow in the direction of the terminal connection with the ignition cable, In the form shown, the combined insulating and heat resisting means referred to comprise a lowerv insulating member H of suitable heat resisting material, such as asbestos, and an upperinsulating memher it preferably molded within cap 93, and provided with a longitudinally elongated portion or boss 2! which is coaxial with part it of the cap,

and forms an insulated entrance for the ignition cable which is adapted for connection to terminal 6 by any suitable means such as the screw shown at 23. Preferably this screw is disposed with its axis in alignment with the axis of the plug 5, and with its upper end pointed to pierce both the insulation and the metal stranded wire which compose the current conducting ignition cable, the head 2% of the screw being in engagement with a conducting Washer 26 fitting within the innermost portion of the recess 21 in the cap it, the said recess being formed by the downwardly extending skirt 28 of the cap. A coil spring 29 surrounds and contacts ring 26 and has its lower end bent downwardly through the central. opening 38 in the member H to be received within the terminal 6 of the plug and thereby complete the electrical circuit to the electrode points i and it.

By reason of the transversely extending por-- tion 48 of the member ii the flow of heat toward the conducting parts adjacent the cable is effectively blocked, and the flow is thus deflected from the metallic elements at and t to the outer surface of the cap i3 and the atmosphere. To supplement member i? in resisting the current conducting elements, I provide washers as and 31, which are also of heat resisting material such as asbestos, the said washers being engageable with the upper and lower surfaces of the rim 39 on the metallic cup so within which the member H is positioned and retained (as by being molded therein) the washer 31 serving as a support for the cup 4!] and the member i1 and being in turn supported by the rim l6 of the shielding element 6. Preferably, the base and sides of the cup 4i? are apertured as indicated at iii and H respectively, and opposite the apertures ii the insulator il ismade of reduced diameter to provide an annular chamber facilitating free radiation of heat from the insulator and into the outer annular chamber by way of apertures ii.

Various changes, which will now appear to those skilled in the art, may be made in the form, details of construction and arrangement of the parts without departing from the spirit of the invention, and reference is therefore to be had to the appended claims for a definition of the limits of the invention.

What is claimed is:

l. A shield for a spark plug and cable conductor comprising a lower shielding member surrounding the plug, an upper shielding member surrounding and receiving the cable conductor, a conducting member connecting said cable conductor and plug, a heat resisting insulator surrounding said conducting member and the upper part of the plug, a metallic cup enclosing said insulator, said cup having a rim contacting said upper shielding member, and a. second member of heat resisting material interposed between said cup and lower shielding member. 2. The combination, with a spark plug shield having upper and lower sections and a wire bail uniting said sections, of a bail receiving cap on said upper section, and means for taking up play between the bail and the bail receiving cap, said last-named means including a pin engageable with said cap to lock the latter in a predetermined position in relation to said bail.

3. A shield for a-spark plug and cable comprising a lower shielding member surrounding the plug, an upper shielding member surrounding and receiving the cable, a conducting member connecting said cable and plug, a heat resisting insulator surrounding said conductor and the upper part of the plug, a metallic cup enclosing said insulator, and a heat radiating chamber between the insulator andcup.

@WARD B. NOWOSIELSH.

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