US2060680A

US2060680A - Electric ignition plug

Info

Publication number: US2060680A
Application number: US624243A
Authority: US
Inventors: Harry J Linse
Original assignee: Individual
Current assignee: Individual
Priority date: 1932-07-23
Filing date: 1932-07-23
Publication date: 1936-11-10
Anticipated expiration: 1953-11-10

Description

Nov. 10, 1936. H. .1. LlNSE ELECTR IC IGNITION PLUG Filed July 23, 1932 INVENTOB filmy Zlmsc BY [1 0 ATTORNE Patented Nov. 10, 1936 UNITED STATES PATENT OFFICE 5 Claims.

This invention relates to electric ignition plugs for use in internal combustion engines for igniting the fuel charge in the engine cylinder embodying a shell whereby it is mounted in an opening in the engine cylinder and constitutes one of the plug electrodes, and a second electrode carried by an insulator body of translucent mate-rial, such as glass, with a portion projecting from the shell arranged with a prismatic surface whereby the light rays of combustion of the fuel are deflected longitudinally through the insulator body and laterally of said projecting portion whereby the burning of the fuel within the engine cylinder may be readily ascertained by observing said projecting portion of the insulator body, as shown in Letters Patent No. 1,846,741 granted to me February 23, 1982.

In the arrangement of ignition plug shown in said Letters Patent the insulator body does not extend for the entire length of the center electrode with the result that an unsupported portion of the electrode extends from the body. To compensate for expansion and contraction of the parts the electrode carrying bore in the insulator body is of greater diameter than the electrode, the electrode being secured in the bore of the insulator body by an enlargement on the electrode engaging the inner end of the insulator body and a nut threaded onto the outer end. To support said extended end of the electrode to prevent distorting of the electrode and thereby a varying in the spark gap a conical member of translucent material was secured in abutting relation to the end of the insulator body and the materials of said conical member-and insulator body having the same co-efficient of expansion, and the electrode loosely extended through a bore into said member. While said arrangement is satisfactory under ordinary fuel compression pressures and heat in the engine cylinder, in the use of such arrangement with high fuel compression pressures, and consequent higher temperatures, such pressures and high temperatures and the expansion of the material of the conical member tend to move the center electrode laterally and this is augmented by the loose engagement of the electrode in the insulator body and supporting member and thus vary the sparking gap by moving the sparking terminal of the center electrode either too close or too far away from the sparking terminal of the shell electrode.

It is the object of the present invention to overcome said disadvantage by providing an improved construction and arrangement of mounting of the center electrode in the insulator body, and to an improved construction and arrangement of supporting member for the end portion of the electrode unsupported by the insulator body, and to provide means for this purpose which is novel, cheap in structure and efiicient in use.

In the drawing accompanying and forming a part of this application Figure 1 is a side elevation of an ignition plug, partly in section, with the present invention embodied therein.

Figure 2 is a longitudinal sectional view of the ignition plug.

Figure 3 is a side elevation, on an enlarged scale, of a center electrode embodied in the present invention.

Figure 4 is a perspective view of the insulator body; and

Figure 5 is a perspective view, partly in section, of the support.

In carrying out the invention there is provided a shell electrode 1 of the usual structure having a skirt portion arranged with external screw threads 8 for engaging the ignition plug in an opening in the cylinder of an internal combustion engine, and. an internal annular shoulder 9 above the skirt portion to form a seat for an annular enlargement I0 intermediate the ends of a section II of a composite insulator core or body to sup port the same within the shell electrode I, and is secured therein by a collar or sleeve 12 engaged within and having threaded connection with the shell electrode with a sealing gasket l3 interposed between the upper portion of the insulator enlargement l0 and said collar, a gasket l3 also being interposed between the lower portion of the enlargement and shoulder 9 to seal the insulator body in the shell to prevent loss of compression in the engine cylinder.

The insulator body I! is of such a size relative to the shell electrode to compensate for thermal expansion and contraction of the metal of the shell and collar, and consists of a transparent or translucent material, preferably glass, having a portion extended beyond the end of the shell electrode that is engaged by the collar [2, arranged with a prismatic surface 14 of suitable form to deflect and diverge the light rays of combustion transmitted longitudinally through the body laterally thereof, and shown as comprising a series of annular flutes. To facilitate the molding of the insulator body it is of a length so that the end opposite the end with the prismatic surface terminates at a point within the threaded skirt 8 of the electrode shell and has a bore 15 of uniform diameter leading from the end with the prismatic surface and terminating in an enlargement H5 at the opposite end, the side wall of which enlargement diverges or tapers slightly toward the end of the insulator body.

The center electrode comprises a rod having two diameters and consisting of a body portion H which may be of uniform diameter and a sparking terminal end portion l8 of reduced diameter. The body portion i1 is screw threaded from the juncture of the body portion, with the reduced portion of the rod to a point intermediate the ends of the body portion, as at IS. The free end of the body portion of the rod is also screw threaded and an annular abutment in the form of a collar or washer 20 is fixed in predetermined position thereon, in the present instance, intermediate the ends of said screw threads, as by swaging or otherwise, said washer being adapted to abut against the end of the insulator body to hold the rod electrode against movement in one direction relative to the insulator body so that the body portion ll of the electrode will terminate within the bore enlargement IS with a portion of the threaded end positioned within the bore of the insulator body, as shown in Figure 2, and thus providing the electrode within the bore of the insulator body with recessed portions and the reduced portion l8 to extend for a predetermined length beyond the skirted portion of shell 1. The threaded as well as the intermediate portion of the body of the electrode is of less diameter than the bore in the insulator body, and the electrode is pressure sealed centrally therein by a suitable cementitious material, as at 2!, the embedding of the cement in the threads at both ends of the electrode body I! serving to hold the electrode against longitudinal displacement and compensate for irregularities in the bore wall, as well as rotary movement, as when screwing a conductor binding nut 22 onto the threaded end of the electrode extended beyond the insulator body to bind an electric conductor between the nut and the abutment washer 2|].

The reduced electrode end i8 extends beyond the threaded end 8 of the shell in spaced relation to a sparking terminal in the form of the usual angular pin 23 secured in the end of the shell, and is supported by the other section of the composite core or body comprising a sleeve 24 and the material having a diiferent co-efiicient of expansion, preferably lower, than the material of the insulator body, in the present instance consisting of a non-translucent and refractory insulator material, such as porcelain having an outer glazed surface. The outer wall of the sleeve tapers from intermediate the ends to the opposite ends, as at 25, 2B, the end 25 being engaged in the enlargement iii of the bore in the insulator body being of a length and substantially equal to the length of said bore enlargement but of slightly less diameter and secured and supported therein by a cementitious material, as at 21. The bore through the sleeve is of slightly greater diameter than the reduced portion I8 of the electrode and the inner end of the bore is arranged with an enlarged threaded portion 29 for threaded connection with the intermediate threaded portion I9 of the rod electrode to positively retain the porcelain sleeve united with the translucent body and co-operate with the rod abutment 20 to secure the electrode against longitudinal displacement. The sleeve terminates at a point within the end of the electrode and may be further secured thereto by a cementitious material interposed between the electrode and sleeve, as at 28. It will be observed that the greatest outer diameter of the electrode supporting sleeve is less than the end wall of the insulator body extending about the sleeve and thus providing a surface for the light rays of combustion to be transmitted longitudinally through the insulator body, and the glazing of the outer surface of the projecting portion of the sleeve serves to reflect and deflect the light rays of combustion to said end wall of the insulator body. The cementitious layer 2i interposed between the insulator body and the body portion ll of the rod electrode also serves as a reflecting surface and facilitates the deflecting of the light rays laterally from the insulator body.

Having thus described my invention I claim:

1. In an electric ignition plug, an insulator body of translucent material having a bore leading therethrough from one end and terminating in an enlargement at the opposite end and having a prismatic exterior surface adjacent one end, a sleeve of non-translucent and insulating material seated at one end in the bore enlargement of the insulator body and having an outer diameter not greater than the diameter of said bore enlargement to expose the end of the insulator body, a cementitious material to secure the sleeve in the bore enlargement in the insulator body, an electrode having two diameters, the portion of less diameter extended through and of less di ameter than the sleeve bore to constitute a sparking terminal, and the portion of, greater diameter extended through and of less diameter than the bore in the insulator body and having recesses therein within said bore and a threaded connection with the sleeve, and cementitious material interposed between the electrode and walls of the sleeve and insulator body in embedding relation to the recesses in the electrode to pressure seal the electrode in the insulator body and sleeve.

2. In an electric ignition plug, an insulator body of translucent material having an exterior prismatic surface at one end and a bore 01 uniform diameter leading therethrough from one end and terminating in an enlargement at the opposite end of the body with the side wall of the enlargement diverging toward the end of the body, a porcelain sleeve having an outer glazed surface and tapering from intermediate the ends to the opposite ends, said sleeve engaged at one end in and the taper of. the outer wall conforming to the taper of the bore enlargement of the insulator body and the sleeve bore being 01 less diameter than and extending coaxially of the bore in the insulator body, and the greatest outer diameter of said sleeve being less than that of the bore enlargement to expose the end wall of the insulator body about the sleeve for the transmitting of light rays longitudinally through the translucent body to be deflected laterally by the prismatic surface, the bore of the sleeve at the end engaged in the bore enlargement of the insulator body being arranged with a screw-threaded enlargement, a rod electrode having two diameters extended through and of. less diameter than, the diameters of the bores in the insulator body and sleeve with the portion of less diameter engaging the bore of the porcelain sleeve and the portion of larger diameter engaging the bore in the insulator body, said portion of larger diameter being screw threaded at both ends for an extent so that a portion of the screw threads is positioned within the bore of the insulator body with the threads adjacent the portion of lean diameter engaging the threads or the bore enlargement of the sleeve to secure the sleeve within the insulator body enlargement and on the electrode and hold the electrode against longitudinal displacement in one direction, and a cementitious material interposed between the electrode and the walls of the bores in the insulator body and sleeve and in embedding relation to the screw threads of. the electrode within the bore of the insulator body to pressure seal the electrode therein.

3. In an electric ignition plug, a composite insulator body embodying endwise secured sections having alined bores therethrough, one section consisting of a translucent material and the other section of a non-translucent refractory material of less cross section than the first section to expose the wall of the first section extending about the second section, and a rod electrode extended through and secured in the bores of and connecting the sections of the insulator body.

4. In an electric ignition plug, a composite insulator core consisting of a body of translucent material having an exterior prismatic surface at one end and a bore therethrough having an enlargement at the end opposite to the end with the prismatic surface and a sleeve of. non-transparent refractory material seated in the bore enlargement of the body and of less diameter than the body to expose the end wall of the body about the sleeve and said sleeve having a bore therethrough arranged with a screw threaded enlargement in the end engaged in the bore enlargement of the insulator body, a rod electrode extended through the bores of the body and sleeve having screw threaded portions at one end and intermediate the ends, and having an abutment fixed thereon intermediate the threaded end portion to engage the end of the translucent body and the intermediate screw threaded portion adapted to have connection with the screw threaded enlargement of the sleeve to connect the sleeve to the translucent body and in connection with the abutment securing the electrode against displacement in the insulator core, and a cementitious material between the electrode and walls of the bores in the insulator body and sleeve in embedding relation to the screw threads of the electrode to pressure seal the electrode in the insulator body and sleeve.

5. In an ignition plug for internal combustion engines, the combination of a shell having an interior annular shoulder intermediate the ends and an externally threaded end portion for mounting in an opening in the engine cylinder, a body of translucent insulator material engaged in the shell having an annular enlargement for seating against the shoulder in the shell, said body having an end portion projecting from the shell arranged with an exterior prismatic surface and a bore through the body, a collar encircling the body and having threaded connection with the shell to engage the annular enlargement of the body and secure it to the seat in the shell, a sleeve of non-transparent and refractory material engaged in the end of the body within the exteriorly threaded portion of the shell and of less diameter than the body to expose the end wall portion of the body about the sleeve within the shell to transmit the light rays of, combustion in the engine cylinder through the body to the prismatic surface and by the latter deflected laterally, and a rod electrode extended through the bores of the body and sleeve, said rod having an abutment fixed adjacent one end to abut the outer end of the translucent body and arranged to connect the sleeve to the translucent body and thereby in conjunction with the abutment held against longitudinal displacement relative to the translucent body and sleeve.

HARRY J. LINSE.