USRE38536E1 - Spark plug and method of producing the same - Google Patents
Spark plug and method of producing the same Download PDFInfo
- Publication number
- USRE38536E1 USRE38536E1 US10/023,157 US2315701A USRE38536E US RE38536 E1 USRE38536 E1 US RE38536E1 US 2315701 A US2315701 A US 2315701A US RE38536 E USRE38536 E US RE38536E
- Authority
- US
- United States
- Prior art keywords
- spark
- spark plug
- electrodes
- layer
- resistant material
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired - Fee Related
Links
- 238000000034 method Methods 0.000 title claims description 24
- 230000003628 erosive effect Effects 0.000 claims abstract description 24
- 239000000463 material Substances 0.000 claims abstract description 22
- 230000008021 deposition Effects 0.000 claims abstract description 8
- 238000009792 diffusion process Methods 0.000 claims description 13
- 238000000151 deposition Methods 0.000 claims description 10
- BASFCYQUMIYNBI-UHFFFAOYSA-N platinum Chemical compound [Pt] BASFCYQUMIYNBI-UHFFFAOYSA-N 0.000 claims description 10
- WFKWXMTUELFFGS-UHFFFAOYSA-N tungsten Chemical compound [W] WFKWXMTUELFFGS-UHFFFAOYSA-N 0.000 claims description 10
- 229910052721 tungsten Inorganic materials 0.000 claims description 7
- 239000010937 tungsten Substances 0.000 claims description 7
- 229910052751 metal Inorganic materials 0.000 claims description 6
- 239000002184 metal Substances 0.000 claims description 6
- 230000001052 transient effect Effects 0.000 claims description 6
- 238000000576 coating method Methods 0.000 claims description 5
- 239000000446 fuel Substances 0.000 claims description 5
- 230000008642 heat stress Effects 0.000 claims description 5
- 229910052697 platinum Inorganic materials 0.000 claims description 5
- 239000011248 coating agent Substances 0.000 claims description 4
- 239000007772 electrode material Substances 0.000 claims description 4
- 239000000758 substrate Substances 0.000 claims description 3
- 230000000737 periodic effect Effects 0.000 claims 4
- 230000035882 stress Effects 0.000 claims 2
- 238000004519 manufacturing process Methods 0.000 claims 1
- 238000002485 combustion reaction Methods 0.000 description 3
- 239000012779 reinforcing material Substances 0.000 description 3
- 238000010276 construction Methods 0.000 description 2
- 238000003466 welding Methods 0.000 description 2
- 239000012212 insulator Substances 0.000 description 1
- 238000003754 machining Methods 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 239000010970 precious metal Substances 0.000 description 1
- 238000007493 shaping process Methods 0.000 description 1
- 238000004544 sputter deposition Methods 0.000 description 1
Images
Classifications
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01T—SPARK GAPS; OVERVOLTAGE ARRESTERS USING SPARK GAPS; SPARKING PLUGS; CORONA DEVICES; GENERATING IONS TO BE INTRODUCED INTO NON-ENCLOSED GASES
- H01T13/00—Sparking plugs
- H01T13/20—Sparking plugs characterised by features of the electrodes or insulation
- H01T13/39—Selection of materials for electrodes
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01T—SPARK GAPS; OVERVOLTAGE ARRESTERS USING SPARK GAPS; SPARKING PLUGS; CORONA DEVICES; GENERATING IONS TO BE INTRODUCED INTO NON-ENCLOSED GASES
- H01T21/00—Apparatus or processes specially adapted for the manufacture or maintenance of spark gaps or sparking plugs
- H01T21/02—Apparatus or processes specially adapted for the manufacture or maintenance of spark gaps or sparking plugs of sparking plugs
Definitions
- the present invention relates generally to spark plugs and methods of producing the spark plugs.
- a spark plug for internal combustion engine usually has a center electrode and another ground electrode, which upon supplying of an electrical potential generate a spark for igniting fuel in an internal combustion engine. Since the ignition is performed many thousand times due to an electrical discharge at the electrodes, the electrodes are subjected to erosion which reduces their service life. In order to increase the service life, it was proposed to apply reinforcing materials on the facing surfaces of the electrodes by the range of different techniques. Some techniques require sophisticated equipment and control, following shaping electrode tips into final configuration (attaching by welding small reinforce metal pieces to electrode ends, inserting metal wire in a hole of central electrode tip, plasma welding technique, etc.).
- a spark plug which includes at least two electrodes producing a spark by an electrical discharge and having ends facing toward one another, wherein an additional layer of the material, in particular tungsten, is applied on the ends of the electrodes facing toward one another by electro-spark deposition.
- the spark plugs When the spark plugs are formed in accordance with the present invention, their erosion resistance and therefore their service life is substantially increased.
- the layer produced on the facing surfaces of the electrodes is finally shaped and its bonding to the electrodes is strong due to the diffusion.
- the diffusion transient zone has linear coefficient of expansion between such of the erosion resistant layer and an electrode material. Thereby, heat stresses that occur on a border between layer and electrode body during the spark plug operation will relieve.
- a method of producing the spark plug is proposed, in accordance with which at least two electrodes are made, and then an additional layer is applied on the end of each electrode facing the other electrodes, the layer composed of tungsten and applied by electro-spark deposition, so that a reliable diffusion bonding is provided between the coating and the spark plug electrode material and heat stresses that occur on a border between the layer and the electrode body during the spark plug operation will be relieved.
- FIGURE of the drawings is a view showing a spark plug in accordance with the present invention.
- a spark plug in accordance with the present invention is identified as a whole with reference numeral 1 . It has a central electrode 2 and an additional ground electrode 3 . The electrodes are arranged so that their ends face one another. When electric potential is applied to the spark plug, a discharge is produced between the facing ends or tips of the electrodes, and generates a spark which ignites a fuel of an internal combustion engines.
- sparks plugs are generally known in the art, and therefore additional elements of the spark plugs, such as insulators, casing, etc. are not shown in the drawings.
- an erosion-resistant layer is applied by electro-spark deposition on an end or a tip of each electrode which faces an end or a tip of another electrode.
- the tips or the faces of the electrodes facing one another are covered with the additional layers of tungsten 3 2 ′, 3 ′, the layers are reliably bonded to the corresponding electrodes, and the heat stresses that occur on a border between the layer and the electrode body during the spark plug operation will be relieved. Since the layer is erosion-resistant, the service life of the electrodes is substantially increased.
- the deposited layer can have a thickness of 10-50 ⁇ m.
- the transient zone formed due to diffusion of the layer material into the substrate of the spark plug electrode relieves heat stresses on the border between the layer and the electrode body during the spark plug operation. Following machining is not needed after the electro-spark deposition.
Landscapes
- Engineering & Computer Science (AREA)
- Manufacturing & Machinery (AREA)
- Spark Plugs (AREA)
Abstract
A spark plug has at least two electrodes having ends facing toward one another so as to produce an electrical discharge when an electrical potential is applied to said electrodes, and a layer of an erosion-resistant material applied on each of said electrodes by electro-spark deposition so the lifetime of the spark plug comparing to existing is substantially increased.
Description
The present invention relates generally to spark plugs and methods of producing the spark plugs.
A spark plug for internal combustion engine usually has a center electrode and another ground electrode, which upon supplying of an electrical potential generate a spark for igniting fuel in an internal combustion engine. Since the ignition is performed many thousand times due to an electrical discharge at the electrodes, the electrodes are subjected to erosion which reduces their service life. In order to increase the service life, it was proposed to apply reinforcing materials on the facing surfaces of the electrodes by the range of different techniques. Some techniques require sophisticated equipment and control, following shaping electrode tips into final configuration (attaching by welding small reinforce metal pieces to electrode ends, inserting metal wire in a hole of central electrode tip, plasma welding technique, etc.). Other processes apply a layer of reinforcing material by sputtering or coating methods which can not provide reliable bonding between the electrode substrate and the layer material at high temperature spark plug operating conditions and could result in failure of a spark plug. Most of techniques use precious metals as a reinforcing material, which have extremely high cost. Some spark plugs of the above mentioned general type are disclosed in U.S. Pat. Nos. 3,673,452, 4,810,220, 4,881,913, 5,179,313, 5,456,624; 5,779,842; etc.
Accordingly, it is an object of the present invention to provide a spark plug and a method of producing the same which avoids the disadvantages of the prior art.
In keeping with these objects and with others which will become apparent hereinafter, one feature of present invention resides, briefly stated, in a spark plug which includes at least two electrodes producing a spark by an electrical discharge and having ends facing toward one another, wherein an additional layer of the material, in particular tungsten, is applied on the ends of the electrodes facing toward one another by electro-spark deposition.
When the spark plugs are formed in accordance with the present invention, their erosion resistance and therefore their service life is substantially increased. The layer produced on the facing surfaces of the electrodes is finally shaped and its bonding to the electrodes is strong due to the diffusion. The diffusion transient zone has linear coefficient of expansion between such of the erosion resistant layer and an electrode material. Thereby, heat stresses that occur on a border between layer and electrode body during the spark plug operation will relieve.
In accordance with another feature of present invention, a method of producing the spark plug is proposed, in accordance with which at least two electrodes are made, and then an additional layer is applied on the end of each electrode facing the other electrodes, the layer composed of tungsten and applied by electro-spark deposition, so that a reliable diffusion bonding is provided between the coating and the spark plug electrode material and heat stresses that occur on a border between the layer and the electrode body during the spark plug operation will be relieved.
The novel features which are considered as characteristic for the present invention are set forth in particular in the appended claims. The invention itself, however, both as to its construction and its method of operation, together with additional objects and advantages thereof, will be best understood from the following description of specific embodiments when read in connection with the accompanying drawings.
The single FIGURE of the drawings is a view showing a spark plug in accordance with the present invention.
A spark plug in accordance with the present invention is identified as a whole with reference numeral 1. It has a central electrode 2 and an additional ground electrode 3. The electrodes are arranged so that their ends face one another. When electric potential is applied to the spark plug, a discharge is produced between the facing ends or tips of the electrodes, and generates a spark which ignites a fuel of an internal combustion engines. These sparks plugs are generally known in the art, and therefore additional elements of the spark plugs, such as insulators, casing, etc. are not shown in the drawings.
In accordance with the present invention, an erosion-resistant layer is applied by electro-spark deposition on an end or a tip of each electrode which faces an end or a tip of another electrode. In accordance with the present invention For example, the tips or the faces of the electrodes facing one another are covered with the additional layers of tungsten 3 2′, 3′, the layers are reliably bonded to the corresponding electrodes, and the heat stresses that occur on a border between the layer and the electrode body during the spark plug operation will be relieved. Since the layer is erosion-resistant, the service life of the electrodes is substantially increased.
The deposited layer can have a thickness of 10-50 μm. The transient zone formed due to diffusion of the layer material into the substrate of the spark plug electrode relieves heat stresses on the border between the layer and the electrode body during the spark plug operation. Following machining is not needed after the electro-spark deposition.
It is believed to be clear that other materials can be used for forming the erosion-resistant layers on the tips or facing ends of the electrode, for example platinum, etc.
It will be understood that each of the elements described above, or two or more together, may also find a useful application in other types of constructions and methods differing from the types described above.
While the invention has been illustrated and described as embodied in spark plug and method of producing the same, it is not intended to be limited to the details shown, since various modifications and structural changes may be made without departing in any way from the spirit of the present invention.
Without further analysis, the foregoing will so fully reveal the gist of the present invention that others can, by applying current knowledge, readily adapt it for various applications without omitting features that, from the standpoint of prior art, fairly constitute essential characteristics of the generic or specific aspects of this invention.
What is claimed as new and desired to be protected by letters patent is set forth in the appended claims:
Claims (27)
1. A spark plug comprising
two electrodes having ends facing toward one another, so that when electrical potential is supplied to the electrodes, an electrical discharge is produced and a spark is generated to ignite a fuel; and
a layer of an erosion resistant material applied to each end of each of said electrodes by the electro-spark deposition so that a reliable diffusion bonding Is is provided between a coating and a spark plug electrode material.
2. A spark plug as defined in claim 1 , wherein said layer of erosion-resistant material is composed of tungsten.
3. A spark plug as defined in claim 1 , wherein said layer of erosion-resistant material is composed of platinum.
4. A spark plug as defined in claim 1 , wherein said layer of erosion-resistant material is composed of a metal of 5-6th period of The Periodic Table.
5. A spark plug comprising
at least two electrodes, said electrodes having ends facing toward one another so as to produce an electric discharge when an electrical potential is applied to said electrodes and to generate a spark for igniting a fuel; and
a layer of an erosion-resistant material applied on each of said ends of each of said electrodes by electro-spark deposition so that a reliable diffusion bonding is provided between the a coating and the spark plug electrode substrate , and heat stresses occurring on a border between the layer and the electrode body, during the spark plug operation, are relived and a lifetime of the spark plugs plug is substantially increased.
6. A method of producing a spark plug, comprising the steps of forming two electrodes having ends facing toward one another so that when electrical potential is supplied to the electrodes an electrical discharge is produced and a spark is generated to ignite a fuel; and applying a layer of an erosion resistant material to each end of each of said electrodes by the electro-spark deposition so that a reliable diffusion bonding is provided between the coating and the spark plug electrode material.
7. A method as defined in claim 6 , wherein said layer of erosion-resistant material is composed of tungsten.
8. A method as defined in claim 6 , wherein said layer erosion-resistant material is composed of platinum.
9. A method as defined in claim 6 , wherein said layer of erosion-resistant material is composed of a metal of 5-6th period of The Periodic Table.
10. A spark plug comprising:
at least two electrodes having respective ends; and
a layer of an erosion resistant material which is electro-spark deposited on a surface of the respective end of at least one of the electrodes.
11. The spark plug according to claim 10 , wherein the surface of the respective end is capable of forming a spark.
12. The spark plug according to claim 10 , wherein the layer is electro-spark deposited on the surface to establish a diffusion bonding between the surface and the layer.
13. The spark plug according to claim 10 , wherein a diffusion transient zone is formed on a border between the deposited layer and the surface of the respective end, and wherein the diffusion transient zone reduces a stress as the border during an operation of the spark plug.
14. The spark plug according to claim 10 , wherein the erosion resistant material includes tungsten.
15. The spark plug according to claim 10 , wherein the erosion resistant material includes platinum.
16. The spark plug according to claim 10 , wherein the erosion resistant material includes a metal of a 5-6th period of The Periodic Table.
17. The spark plug according to claim 10 , wherein the at least two of the electrodes face toward one another.
18. The spark plug according to claim 10 , wherein the layer is electro-spark deposited on the surface of the respective end of each of the at least two electrodes.
19. A method for producing a spark plug, comprising the steps of:
providing at least two electrodes having respective ends; and
electro-spark depositing a layer of an erosion resistant material on a surface of the respective end of at least one of the electrodes.
20. The method according to claim 19 , wherein the surface of the respective end is capable of forming a spark.
21. The method according to claim 19 , wherein the electro-spark depositing step establishes a diffusion bonding between the surface and the layer.
22. The method according to claim 19 , wherein a diffusion transient zone is formed on a border between the deposited layer and the surface of the respective end, and wherein the diffusion transient zone reduces a stress at the border during an operation of the spark plug.
23. The method according to claim 19 , wherein the erosion resistant material includes tungsten.
24. The method according to claim 19 , wherein the erosion resistant material includes platinum.
25. The method according to claim 19 , wherein the erosion resistant material includes a metal of a 5-6th period of The Periodic Table.
26. The method according to claim 19 , wherein the at least two of the electrodes face toward one another.
27. The method according to claim 19 , wherein the electro-spark depositing step is performed on the surface of the respective end of each of the at least two electrodes.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US10/023,157 USRE38536E1 (en) | 1999-03-04 | 2001-12-18 | Spark plug and method of producing the same |
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US09/262,633 US6265815B1 (en) | 1999-03-04 | 1999-03-04 | Spark plug and method of producing the same |
| US10/023,157 USRE38536E1 (en) | 1999-03-04 | 2001-12-18 | Spark plug and method of producing the same |
Related Parent Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| US09/262,633 Reissue US6265815B1 (en) | 1999-03-04 | 1999-03-04 | Spark plug and method of producing the same |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| USRE38536E1 true USRE38536E1 (en) | 2004-06-22 |
Family
ID=22998351
Family Applications (2)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| US09/262,633 Expired - Lifetime US6265815B1 (en) | 1999-03-04 | 1999-03-04 | Spark plug and method of producing the same |
| US10/023,157 Expired - Fee Related USRE38536E1 (en) | 1999-03-04 | 2001-12-18 | Spark plug and method of producing the same |
Family Applications Before (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| US09/262,633 Expired - Lifetime US6265815B1 (en) | 1999-03-04 | 1999-03-04 | Spark plug and method of producing the same |
Country Status (1)
| Country | Link |
|---|---|
| US (2) | US6265815B1 (en) |
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US20060028106A1 (en) * | 2004-08-03 | 2006-02-09 | Lineton Warran B | Ignition device having a reflowed firing tip and method of making |
| US20080036353A1 (en) * | 2006-08-08 | 2008-02-14 | Federal-Mogul World Wide, Inc. | Ignition device having a reflowed firing tip and method of construction |
| US20080185948A1 (en) * | 2007-02-02 | 2008-08-07 | Lineton Warran B | Spark plug electrode and process for making |
Citations (10)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US3673452A (en) * | 1970-09-21 | 1972-06-27 | Ronald F Brennen | Spark plug |
| US4551603A (en) * | 1971-04-02 | 1985-11-05 | Rocklin Isadore J | Device and method for surfacing a workpiece |
| US4810220A (en) | 1988-06-06 | 1989-03-07 | Allied-Signal Inc. | Method for manufacturing electrodes for a spark plug |
| US4826462A (en) * | 1988-08-19 | 1989-05-02 | Champion Spark Plug Company | Method for manufacturing a spark plug electrode |
| US4881913A (en) | 1988-06-16 | 1989-11-21 | General Motors Corporation | Extended life spark plug/igniter |
| US5179313A (en) | 1989-08-11 | 1993-01-12 | Ford Motor Company | Forming an erosion resistant tip on an electrode |
| US5456624A (en) | 1994-03-17 | 1995-10-10 | Alliedsignal Inc. | Spark plug with fine wire rivet firing tips and method for its manufacture |
| US5465022A (en) * | 1992-08-12 | 1995-11-07 | Nippondenso Co., Ltd. | Spark plug for internal-combustion engine and manufacture method of the same |
| US5779842A (en) | 1994-01-25 | 1998-07-14 | Ford Global Technologies, Inc. | Forming an erosion resistant coating on an electrode |
| US5897966A (en) * | 1996-02-26 | 1999-04-27 | General Electric Company | High temperature alloy article with a discrete protective coating and method for making |
-
1999
- 1999-03-04 US US09/262,633 patent/US6265815B1/en not_active Expired - Lifetime
-
2001
- 2001-12-18 US US10/023,157 patent/USRE38536E1/en not_active Expired - Fee Related
Patent Citations (10)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US3673452A (en) * | 1970-09-21 | 1972-06-27 | Ronald F Brennen | Spark plug |
| US4551603A (en) * | 1971-04-02 | 1985-11-05 | Rocklin Isadore J | Device and method for surfacing a workpiece |
| US4810220A (en) | 1988-06-06 | 1989-03-07 | Allied-Signal Inc. | Method for manufacturing electrodes for a spark plug |
| US4881913A (en) | 1988-06-16 | 1989-11-21 | General Motors Corporation | Extended life spark plug/igniter |
| US4826462A (en) * | 1988-08-19 | 1989-05-02 | Champion Spark Plug Company | Method for manufacturing a spark plug electrode |
| US5179313A (en) | 1989-08-11 | 1993-01-12 | Ford Motor Company | Forming an erosion resistant tip on an electrode |
| US5465022A (en) * | 1992-08-12 | 1995-11-07 | Nippondenso Co., Ltd. | Spark plug for internal-combustion engine and manufacture method of the same |
| US5779842A (en) | 1994-01-25 | 1998-07-14 | Ford Global Technologies, Inc. | Forming an erosion resistant coating on an electrode |
| US5456624A (en) | 1994-03-17 | 1995-10-10 | Alliedsignal Inc. | Spark plug with fine wire rivet firing tips and method for its manufacture |
| US5897966A (en) * | 1996-02-26 | 1999-04-27 | General Electric Company | High temperature alloy article with a discrete protective coating and method for making |
Cited By (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US20060028106A1 (en) * | 2004-08-03 | 2006-02-09 | Lineton Warran B | Ignition device having a reflowed firing tip and method of making |
| US7385339B2 (en) | 2004-08-03 | 2008-06-10 | Federal Mogul World Wide, Inc. | Ignition device having a reflowed firing tip and method of making |
| US20080036353A1 (en) * | 2006-08-08 | 2008-02-14 | Federal-Mogul World Wide, Inc. | Ignition device having a reflowed firing tip and method of construction |
| US7851984B2 (en) | 2006-08-08 | 2010-12-14 | Federal-Mogul World Wide, Inc. | Ignition device having a reflowed firing tip and method of construction |
| US20110057554A1 (en) * | 2006-08-08 | 2011-03-10 | Zdeblick William J | Ignition Device Having a Reflowed Firing Tip and Method of Construction |
| US20080185948A1 (en) * | 2007-02-02 | 2008-08-07 | Lineton Warran B | Spark plug electrode and process for making |
| US7795790B2 (en) | 2007-02-02 | 2010-09-14 | Federal-Mogul Worldwide, Inc. | Spark plug electrode and process for making |
| US20100273385A1 (en) * | 2007-02-02 | 2010-10-28 | Lineton Warran B | Spark plug electrode and process for making |
Also Published As
| Publication number | Publication date |
|---|---|
| US6265815B1 (en) | 2001-07-24 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| EP2013953B1 (en) | Spark plug | |
| US5132587A (en) | Spark plug electrodes | |
| US4881913A (en) | Extended life spark plug/igniter | |
| KR100965741B1 (en) | Spark plug and method for manufacturing the same | |
| US5731654A (en) | Spark plug having a creepage spark gap | |
| US6819031B2 (en) | Spark plug and a method of producing the same | |
| US5461210A (en) | Method of manufacturing a spark plug electrode | |
| USRE34778E (en) | Spark plug and method of manufacturing the same | |
| CN101507067A (en) | Spark plug with fine wire ground electrode | |
| EP0575163A1 (en) | A spark plug | |
| US5497045A (en) | Spark plug having a noble metal electrode portion | |
| KR20090004919A (en) | Spark plug | |
| WO2004008596A2 (en) | Ignition device having an electrode formed from an iridium-based alloy | |
| US4771209A (en) | Spark igniter having precious metal ground electrode inserts | |
| US7816845B2 (en) | Ceramic electrode and ignition device therewith | |
| US6232704B1 (en) | Spark plug with specific electrode structure | |
| US4910428A (en) | Electrical-erosion resistant electrode | |
| JP4255519B2 (en) | Spark plug for internal combustion engine and method for manufacturing the same | |
| US20070188064A1 (en) | Metallic insulator coating for high capacity spark plug | |
| USRE38536E1 (en) | Spark plug and method of producing the same | |
| US6833658B2 (en) | Middle electrode with precious metal reinforcement and a process for producing the same | |
| CA1168531A (en) | Spark igniter | |
| CN1198848A (en) | Electrode for spark plugs of internal combustion engines and process for manufacturing the same | |
| US6455988B1 (en) | Spark plug having a particular resistor | |
| US6956319B2 (en) | Structure of spark plug designed to provide higher wear resistance to center electrode and production method thereof |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| AS | Assignment |
Owner name: DAY ALLOYING L.L.C., NEW YORK Free format text: ASSIGNMENT OF ASSIGNORS INTEREST;ASSIGNOR:REZNIK, ALEXANDER;REEL/FRAME:015829/0285 Effective date: 20040923 |
|
| FPAY | Fee payment |
Year of fee payment: 4 |
|
| SULP | Surcharge for late payment | ||
| FEPP | Fee payment procedure |
Free format text: PAYOR NUMBER ASSIGNED (ORIGINAL EVENT CODE: ASPN); ENTITY STATUS OF PATENT OWNER: SMALL ENTITY |
|
| FPAY | Fee payment |
Year of fee payment: 8 |
|
| REMI | Maintenance fee reminder mailed | ||
| LAPS | Lapse for failure to pay maintenance fees |