US1448656A - Spark plug - Google Patents

Description

Mar. 13, 1923.

A. J. 'DONLEY SPARK PLUG Filed Aug. 18, 1920 Patented Mar. 13, 1923.;

umrso STATES ARTHUR J. DONLEY,

PATENT OFFICE...

or cnrcaeo, ILLINOIS.

SPARK PLUG.

Application filed August 18, 1920. Serial No. 404,382.

of Illinois, have invented a new and useful disconnected due to vibration and which will at all times maintain a good electrical connection, although .readily' detachable without the use of tools.

One of the features of the invention resides in a sleeve or tubular member em- .bedded in the insulating block of the plug, and forming a socket and an. electrode embedded, in the lower portion ofthe block with its upper end terminating at the lower end of said tube and in substantial alinement with the longitudinal axis thereof, thereby forming an intensifying gap between the lowerend of the tube and the upper end of the electrode.

Another feature. of the invention resides in said tubular socket being adapted to receive a plug terminal which. extends thereinto with a frictional sliding fit thus enabling quick attachment and detachment of the terminal without the need of tools and the labor now required by other spark plugs, and eliminating washers; nuts, threaded rods and clamps which work loose through vibration and destroy the electrical connection. 1

The invention further resides in the sundry details of construction, organization, and combination of parts hereinafter more fully described.

In this specification and the annexed drawings, the invention is disclosed in the form in which it is considered to be the best, but the invention is not limited to such form because it is capable of being embodied in other forms; and it is to be understood that in and by the claims following the description herein, it is intended to cover the invention in whatever form it may embody'within the scope thereof.

In the drawings:

Figure 1 is a longitudinal sectional view taken through the spark plug constructed in accordance with the invention,

-Fig. 2 is a transverse sectional view taken substantially on line 2-2 of Fig. 1, and

Fig. 3 is a perspective view of the insulating block.

The s ark plug comprises a hollow metallic-mem er or casing 1, externally threaded at its inner end and provided at its opposite end with a polygonal head. to recelve a wrench in the placing and removing of a plug. This casing has suitably secured to its lower end an inwardly lateral extending arm 2 PI'OVldlIlg one of the electrodes of the plug, in a manner which is usual in connection with the devices of this character.

The insulating plug 3 is formed of fiber, porcelain or other suitable material, andhas an exterior contour which is common to most plugs, that is having an enlarged central portion forming a shoulder 4', which rests-on a shoulder 5 provided on the interior of the casing 1. A binding nut 6 fits over the upper end of. the casing. This bindingnut engages on the opposite side a: of the shoulder 4, to clamp the insulating block firmly in the casing against the shoulder 5 thereof, there being a suitable washer or gasket 7 between the shoulders 4 and 5 so as to provide an air and gastight joint.

The insulating block is formed also with a longitudinal bore, substantially the upper half of the bore being enlarged, inthe manner shown in the drawings. A metallic tube 8, of any suitable material which is a good electrical conductor is tightly fitted in the upper or enlarged portion of the bore and is held in place by cement or in any other suitable'manner, the upperend of the tube 8 terminating and being flush with the upper end of the insulating block.

In the lower portion of the bore is tightl fitted the other'electrode 9, of the plug en 7 as will be observed from the drawings, lies in substantial alinement with the longitudinal axis of the tube 8, having the upper or inner end thereof terminating slightly with-, in the lower end of the tubular member, while its lower end projects for a distance beyond the lower end of the insulatin block to cooperate with the electrode 2 for the purpose of producing an electrical spark for igniting the exp osive mixture in the combustion chambers of the engines.

It will be observed that the tubular member 8 provides a socket to'receive 'a connecting terminal, and, by reason of its disposition and relation relative to the electrode 9, an

auxiliary spark gap is provided between its lower end and'the upper end a of the electrode 9, which intensifies the spark occurring at the point 6 in the combustion chamber. It will also be observed that the construction of the insulating block, just described, is extremely simple, possessing but three elements which may be assembled with extreme ease without necessitating skilled workmen and can be produced at a very low. cost, while at the same time provides a spark plug with 'an intensifying gap which has heretofore only been provided with considerable additional cost.

The tubular or socket member 8 receives the projecting end 10 of a plug terminal 11. The end 10 of the terminal preferably has the same cross section as the socket and is of any suitable conductive material and is suitably slotted as at 0, to give it a lateral resiliency in order that the end 10 will tightly and frictionally engage the interior wall of the socket 8. This connection of the terminal 11 with the spark plug permits of a rotating or oscillating movement between the end 10 of the terminal and the socket, thereby having a free movement to compensate for any torsional twist, or strain on the terminal caused by vibration. ,Moreover, this terminal connection permits ready attachment and detachment of it from the spark plug by a mere longitudinal pull on the terminal and eliminates all nuts, washers, threaded rods, clamps and other similar cap members which require considerable effort and tools to manipulate. Furthermore, the ordinary spark plu having clamps and screw-threaded parts or securing the terminal to the plug, require constant attention because the terminal works loose by reason of the vibration set up by the engine and traction, and destroys the electrical 00111160- tion. It is readily appreciated that this is the source of constant annoyance and often causes the engine to knock and jolt, and the operator usually goes to considerable work and inspection before he has realized that the trouble is due to a loose connection with a spark plug.

,ese

By reason of this terminal connection the liability of short-circuiting is largely. reduced because the insulated and enlarged handle portion d of the terminal overlies the upper end of the tubular socket 8, and abuts the upper surface of the insulating block 3, as clearly shown in Figure 1. In the usual type of spark plug the opposite end of the electrode projects from the upper end of the insulating block, and should a tool or other piece of metallic material come in contact therewith it short-circuits the spark plug. Moreover the upper end of the electrodes in the usual spark plug very often becomes broken ofi and thereby destroys the plug.

From the foregoing it will be apparent that the spark plug according to the present invention is extremely simple and'that the tubular member 8 forms a two-fold purpose of providing a socket having an improved terminal connection with the plug, and for providing an intensif ing gap for the current. It will further e apparent that after the life of the plug of this invention, the entire plug need not be discarded, but may be repaired by simply removing the lock-nut 6 and then withdrawing the insulating block 3, which is extremely inexpensive and may be supplied at one-fourth the cost of new plu s.

Vhat claim is:

1. As an improvement in spark plugs, an insulating block, an electrode in said block, an electro-c'onductive tubular member forming a terminal socket in said block and spaced from the electrode to provide an intensifying gap with the latter, and an electro-terminal plug removably inserted in said tubular socket and in electrical contact therewith and out of contact with said electrode. 2. As an improvement in spark plugs, an insulating block, an electro-conductive tubular member forming a terminal socket in said block, an electrode in said block and arranged in substantial alinement with the longitudinal axis of the tubular member and entering the lower end of the socket for providing an intensifyin gap, and an electro-terminal plug remova ly inserted in said socket.

3. As an improvement in spark plugs, an insulating block, an electro-conductive tubular member forming a terminal socket in said block, and an electrode in said block having its inner end extending in the inner end of said tubular member for providing an intensifying gap with'the latter, and an electro-terminal therewith and out of contact with said electrode.

4. As an improvement in spark plugs, an

insulating block having alongitudinal bore tive to each other to provide an intensifytherein, the upper portion of said bore being ing gap and an electro-terminal plug removenlarged, an electro-conductive tubular memably inserted in said tubular member. 10 ber secured in the enlarged portion of the .In testimony whereof I have hereunto set bore, an electrode in the smaller portion of my hand.

said bore, the inner ends of said tubular member and electrode being positioned rela- ARTHUR J DONLEY.

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