US2900546A - Spark plug assembly - Google Patents

Description

Aug. 18, 1959 A. c. RUSSELL SPARK, PLUG ASSEMBLY Filed July 9, 1956 INVENTOR Anci/few 6.' offe A70/PNE y United States Patent O SPARK PLUG ASSEMBLY Andrew C. Russell, Shawnee, Okla. Application July 9, 1956, Serial No. 596,631

2 Claims. (Cl. 313-125) This invention relates generally to the field of internal combustion engine components and, more particularly, to an improvement in spark plug assemblies for use with such engines.

The contact portions of a spark plug assembly between which the spark passes to provide an ignition source for combustible material within the cylinder or combustion chamber of an engine are subject to progressive pitting, erosion and contamination having a profound effect upon the quality of the spark produced and, therefore, the eiiiciency of the engine, as is well known. With conventional types of spark plug assemblies, such circumstance requires relatively frequent removal of the plugs from the engine for cleaning or/and resetting and, even with such regular maintenance, the useful life of the conventional plugs are extremely limited by virtue of the fact that all sparking must occur between a single, invariable pair of portions of the assembly normally comprising xed, opposed, hot and grounded contacts. Obviously, such conventional assemblies permit of only a limited amount of cleaning and readjustment before they rrr-ust be discarded.

It is the primary object of this invention to provide an improved spark plug assembly having a longer, over all useful life and adapted for periodic readjustment as may be required without removal of the assembly from the engine block.

It is another important object of the invention to provide such an improved spark plug assembly `in which one of the pair of contact surfaces between which the spark is formed, preferably the grounded one, is generally annular and the other of such surfaces is shiftable into different positional relationships with said one surface.

It is another important object of the invention to provide such an assembly wherein the other or hot contact surface may be shifted rotationally of the one or grounded annular surface in order to utilize different portions of the latter presenting a clean, unpitted area after a pre-` viously used portion thereof has become pitted or dirty, all without removal of the assembly from the engine or the necessity of cleaning the previously used portion ofv the annular surface.

AIt is another important object of the invention to provide such an assembly wherein the spacing of the two surfaces between which the spark passes may be selectively varied without removal of the assembly from the engine to provide for optimum sparking and efficiency ofV combustion within the engine. Y

. It is another important object of the invention to pro' vide such improved spark plug assemblies, which may be manufactured at relatively low cost and are adapted for use in conventional engines by simple substitution thereof f or the conventional spark plug assemblies normally used in such engines.

Still other important objects of the invention, includingcertain significant details of construction, will be p 2,900,546 Patented VAug. 1 8, 1,959k

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following descripbroken away and shown in cross section for clarity of illustration;

Fig. 2 is a bottom plan view of the spark plug asf' sembly of Fig. l;

Fig. 3 is a side elevational view of a modified form of spark plug assembly made in accordance with the invention, parts being broken away and shown in section for clarity of illustration; and

Fig. 4 is a bottom plan View of the assembly shown in Fig. 3.

Referring first particularly to Figs. 1 and 2 of the accompanying drawing, the preferred form of improved spark plug is generally designated by the numeral 10. Assembly 10 broadly includes, a two-piece, sectioned, tubular steel shell or casing generally designated 12, an elongated, tubular body of insulating material, such as ceramic or porcelain, generally designated 14 extending into and carried by the casing 12, an elongated, metal electrode generally designated 16 extending through the tube or body 14 and the casing 12, and a lateral, metal extension generally designated 18 on the end of electrode' 16 normally disposed within the combustion chamber of an engine, extension 18 cooperating with a portion here'- inafter to be identied of the casing 12 to present opposed surfaces between which the desired spark may jump.

In the preferred embodiment of the invention shown in Figs. 1 and 2, effort has been made to maintain they The casing 12 includes an upper section 26 thrcadably connected as at 28 into a lower section 30 having adjacent'v its bottom extremity external threads 32 adapted forV screwing the assembly 10 intothe block of a conven-V` The upper casing tional internal combustion engine. section 26 preferably includes a hexagonal wrench-receiving surface 34, while the lower section 30 may be: provided with an annular knurled surface 36, as is customary.

The externally flanged portion 22 of body 14 is tightly held between upper and lower sections 26 and 30 'off casing 12, as will be clear in Fig. 1, an upper sealing ring 3S of resilient material being provided between the lowermost extremity of section 26 and body portion 22, and a lower sealing ring 40 of resilient material being provided between the upwardly facing, frusto-conical, internal surface 42 of section 30 and body portionV 22. Such rings 38 and 4'0 effect a gas tight seal between the body 14 and the casing 12 when the section 26 is tightly screwed into the section 30. Y

Tubular body 14 has an elongated bore 44V extending through portion 20 and communicating at its lowermost` end with an aligned bore 46 of lesser diameter. Received'V within the bore 44 is an internally threaded metal sleeve' 48 extending the length of body portion 20 and having' its lowermost end seated on an internal shoulder at the lower extremity of bore 44 as at 50. Sleeve 48 is permanently mounted within bore 44 of body 14 asby'- press tting or bonding during the manufacture of the, ceramic body 14. Sleeve 48 preferably includes an inf y tegral, annular, external ange 52 at its uppermost endv overlying the upper extremity of body portion 20.

Electrode 16 includes an externally threaded intermediate portion 54 threadably received within sleeve 48; an externally threaded uppermost portion 56 of lesser diameter extending upwardly out of sleeve 48 through a washer 58 and nut 60 thereon and receiving lat its uppermost extremity an internally threaded cable terminal cap 62; and a lowermost externally smooth, elongated portion 64 extending downwardly from intermediate portion 54 through the lowermost body portion 24.

, On the lowermost end of electrode portion 64, the electrode 16 is provided with an L-shaped lateral extension 18 having a laterally extending leg 66 rigidly interconnected with the electrodeportion 64 as by Welding at 68 and, preferably, a shorter leg 70 extending upwardly toward a lowermost annular surface 72 presented on the bottom extremity of lower casing section 30. It will be clear to those skilled in the art that the gap across which the ignition spark passes is that presented between the leg 70 of lateral electrode extension 18 and whatever portion of annular surface 72 of lower casing section 30 is then directly opposed by the leg 70 by virtue of the condition of rotation of the electrode 16, the hot lead of the ignition system being coupled with cap 62 and the metallic electrode 16 providing a circuit path to the leg 70, while the casing section 30, including its surface 72, is grounded by virtue of the connection of casing section 30 with the engine block by means of threads 32.

. It will be clear that the portion of the casing surface 7&2 utilized as the grounded part of the spark gap can be changedat will, without removal of the assembly 10 from an engine block, simply by rotation of the electrode 16 within the sleeve 48, it being noted vthat the interconnecting threads of sleeve 48 and intermediate electrode portion 54 are preferably of sufficiently fine pitch to cause no material change in spacing between leg 70 of extension 18 and surface 72 of casing 12 during a single revolution of the electrode 16 within sleeve 48. It will also be observed, however, that the intermediate electrode portion 54 is sufficiently shorter than the sleeve 48 to permit of the electrode 16 being rotated several complete revolutions within the sleeve 48, whereupon the spacing between leg 70 and surface 72 may be controllably varied in substantially continuous and, if the pitch of the interconnecting threads between sleeve 48 and electrode 16 is known, precisely measured amounts.

Once the electrode 16 has been set to its desired position providing an optimum original or reset relationship between the extension leg 70 and an opposing portion of the casing surface 72, the electrode 16 may be releasably locked in such position by tightening the locknut 60 upon washer 58 and flange 52 of sleeve 48. When resetting or readjustment is required, the nut 60 may be loosened and the electrode 16 rotated either a small amount, such as forinstance, /sth revolution, to select a clean and unpitted portion of surface 72, or rotated several revolutions to change the spacing between leg 70 and surface 72, then the nut 60 may be retightened to again lock the electrode 16 in its desired position.

Referring now to the modified form of the invention illustrated in Figs. 3 and 4, the modified assembly is generally designated by the numeral 100 and broadly includes an elongated, tubular, metallic casing generally designated 112, an elongated tubular body or sleeve of ceramic, porcelain or other insulating material generally designated 114, an elongated, metallic electrode generally designated 116, and a laterally extending contact element generally designated 118.

Y Thecasing 112, although generally approximating the external appearance of conventional spark plug assemblies, may be integrally formed as a single unitary piece provided with a generally cylindrical bore 120 having its upper extremity internally threaded as at 122. The casing 112 is externally threaded as at 1 24 adjacent its lower extremity for threadably mounting the assembly 100 in a conventional engine block, and the casing 112 is further provided at its lowermost end with an annular, grounded sparking surface 126.

The insulating body or sleeve 114 is generally cylindrical, although preferably inwardly tapered as at 128 adjacent its uppermost end. The electrode 116 includes an elongated intermediate portion 130 extending through a longitudinal bore 132 in the insulating body 114; an uppermost, externally threaded portion 134 extending through a resilient' sealing and insulating washer 136, a lock nut-138 and into an internally threaded cable terminal cap 140 received thereon; and a lowermost substantially cylindrical ball portion-142 separated from the lowermost end of intermediate portion by an inwardly extending annular groove 144 presenting an upwardly facing shoulder 146 on the ball 142 and an opposed, down- Ywardly facing shoulder 148 on the lower end of intermediate electrode portion 130. Intermediate electrode portion 130 is also provided just below the lower end of insulating body 114 with an integral outturned annular flanged 150 bearing against a resilient Washer 152 interposed between the flange 150 and the lower end 154 of body 114.

Above the body 114, the intermediate electrode portion 130 passes through an insulating sleeve 156 having 0n its lowermost extremity an outturned annular ilange 158 resting upon the upper end 160 of body 114. An externally threaded metallic sleeve 162 provided with suitable tool receiving indentations 164 in its upper surface circumscribes the sleeve 156 and has its lower end bearing against the upper end of body 114. Such metallic sleeve 162 is threadably received by the internal threads 122 adjacent the upper extremity of casing 12.

The intermediate portion 130 of electrode 116 is preferably permanently bonded to the ceramic body 114, although electrode portion 130 may be removably received within bore 132 of body 114, if desired` lt will be clear that the position of body 114, which is slidably and rotatably received within casing 112 is determined by the dual adjustment of the sleeve 162 and the locknut 138. rl`hus, assuming first that the body 114 is bonded to the electrode portion 130, loosening and removal of the cap 140, nut 138 and washer 136 will permit insertion of a suitable tool to engage sleeve 162 for rotating the same to raise or lower the upwardly limiting stop for reciprocatory adjustment of body 114 within casing 112. At the same time, the rotational position of the body 114 and electrode 116 may be adjusted by applying rotative force to the exposed portion 134 of electrode 116. It will be noted that there is preferably sufficient frictional interengagement between the insulating sleeve 156 and electrode portion 130 to prevent the body 114 and electrode 116 from dropping downwardly out of the casing 112 during adjustment of sleeve 162, although it will be clear to those skilled in the art that a special tool which threads upon electrode portion 134 could be used for adjusting the sleeve 162 while at the same time holding the electrode 116. After the sleeve 162 has been set to the desired position, the washer 136 and nut 138 may be replaced and tightened to hold the electrode 116 and body 114 in place, by virtue of the holding action of ange 150 and washer 152 upon the lowermost end 154 of body 114.

It will be appreciated that the adjustment just de scribed is the most radical one to which the assembly 100 would normally ever be subjected and that same should be necessary only on initial installation when the assembly 100 would likely be disengaged from the engine block and a suitable clearance gauge utilized for establishing the desired initial gap between the surface 126 and a part of the laterally extending element 118 hereinafter to be more fully described. For minor adjustments of spacing between the element 118 and surface 126, same may normally be accomplished, assuming that the ange 158 of sleeve 156 and the washer 136 are of resilient material as preferred, simply by varying the degree of tightening of nut 138 upon threaded electrode portion 134. It will be clear that in this modified embodiment of the invention, the electrode 116 may be rotated relative to the casing 112 without any change whatsoever in the spacing between the element 118 and the surface 126, since the reciprocatory adjustment of electrode 116 does not depend on its rotated position at all.

The element 118 comprises a substantially spherical shell 166 provided with a cylindrical opening 168 at its uppermost end of dimensions adapted to receive the portion 170 of electrode 116 between shoulder 148 of electrode portion 130 and shoulder 146 of b'all portion 142. Shell 166 also is provided with a plurality of slits 172 spaced around the upper portion thereof to permit a number of uppermost resilient fingers 174 thereon, it being observed that it is actually the lingers 174 which are adapted to fit within the groove 144 of electrode 116. As will be clear from Fig. 3, the shell 166 is adapted for a snap-on fit onto the ball portion 142 of electrode 116, with the engagement of lingers 172 within groove 144 and between shoulders 146 and 148 preventing any substantial shifting of the shell 166 upon the ball 142, other than complete removal thereof, except that shell 166 may be rotated about the longitudinal axis of electrode 116 upon overcoming the rather strong frictional interengagement between fingers 174 and electrode portion 170.

A laterally extending contact element 176 is secured upon the shell 166 as by welding at 178 and extends to a position disposing the outermost stretch thereof in spaced, proximate, opposition to the grounded surface 126 of casing 112. Although, if desired, a part (not shown) similar to the leg 70 of the above described extension element 18 could be provided upon the element 118, it has been found that same may be omitted with good results still being obtained. It will be clear that the element 118 may be shifted into opposition with different portions of the grounded contact surface 126 of casing 112 either in the manner above-mentioned as involving rotation of the entire electrode 116 or by simply removing the assembly 100 from the engine block and rotating the shell 166 upon ball 162 against the strong frictional interengagement between fingers 174 and electrode portion 170.

It will be clear to those skilled in the art that the two embodiments selected for illustrating the principles of the invention could be varied, modified, or partially combined in a number of ways without departing from the true spirit and intention of the invention. Accordingly, it is to be understood that the invention should be deemed limited only by the scope of the claims that follow.

Having thus described the invention, what is claimed as new and desired to be secured by Letters Patent is:

l. In a spark plug, an elongated, tubular metal casing provided with a substantially fiat, annular, sparking surface on one end thereof and in a plane substantially perpendicular to the longitudinal axis of the casing; an elongated, metal electrode extending through said casing and beyond both ends of the latter; structure mounting said electrode upon said casing in electrically insulated relationship to the latter; a laterally extending, metal extension releasably mounted on the end of the electrode extending beyond said one end of said casing and having a sparking part thereof disposed in spaced, proximate relationship to a segment only of said sparking surface of said casing, said extension always being in substantially the same disposition relative to the electrode longitudinally of the latter; means for shifting said extension longitudinally relative to said casing Without shifting said extension rotationally relative to said casing; and means for shifting said electrode rotationally relative to said casing without shifting said electrode longitudinally relative to said casing.

2. In a spark plug as set forth in claim 1, wherein said last mentioned means mounts said extension upon said electrode for shiftable relative positioning thereof rotationally of the electrode without substantially altering the relative positioning of said extension and said electrode longitudinally of the latter.

References Cited in the tile of this patent UNITED STATES PATENTS 1,139,694 Marean May 18, 1915 1,192,602 Bond July 25, 1916 1,211,157 Hughes Jan. 2, 1917 1,337,679 Williams Apr. 20, 1920 1,525,707 Wetzel Feb. 10, 1925 1,543,628 Stover June 23, 1925 1,691,760 Fox Nov. 13, 1928 2,195,543 Songer Apr. 2, 1940

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