US3818555A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method of manufacturing central electrode for spark plug
Assignee: Denso Corp
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Filing: 1973-03-16
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Granted: 1974-06-25
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Expires: 1993-03-16
Abstract
Abstract A method of manufacturing a central electrode for a spark plug in which an elongated rod consisting of a core of highly heat conductive metal and an outer sheath of corrosion and heat resisting metal is cut into predetermined lengths to obtain unit rods, and part of the core is removed from the firing end of the unit rod to leave a recess in such end. Subsequently, the outer sheath portion surrounding the recess is bent inwardly to close completely the firing end without using any brazing material.
Inventors
- 👤 T Yamaguchi
- 👤 K Izumi
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-05 21:20
CPC Classifications
H; H01; H01T; H01T21/00; H01T21/02
Claims Analysis
Total Claims: 7
Claim 1
Independent Claim
127 words
A method of manufacturing a center electrode for a spark plug comprising the steps of cutting an elongated rod consisting of a core of highly heat conductive material and an outer sheath of corrosion and heat resisting material into unit rods of predetermined length, removing part of said core of highly heat conductive material from one end, termed the firing end, of said unit rod to leave a recess in the firing end, and applying a force to the firing end for bending the portion of said outer sheath of corrosion and heat resisting material surrounding said recess inwardly so as to bring said outer sheath portion into intimate contact with the corresponding portion of said core of highly heat conductive material thereby closing said firing end.
Claim 2
Independent Claim
127 words
A method of manufacturing a center electrode for a spark plug comprising the steps of cutting an elongated rod consisting of a core of highly heat conductive material and an outer sheath of corrosion and heat resisting material into unit rods of predetermined length, removing part of said core of highly heat conductive material from one end, termed the firing end, of said unit rod to leave a recess in the firing end, and applying a force to the firing end for bending the portion of said outer sheath of corrosion and heat resisting material surrounding said recess inwardly so as to bring said outer sheath portion into intimate contact with the corresponding portion of said core of highly heat conductive material thereby closing said firing end.
Claim 3
Dependent Claim
103 words
A method as claimed in claim 1, wherein said force applying step comprises the step of bending the outer sheath portion of corrosion and heat resisting material inwardly at an angle of 45* to 80* to constrict the diameter of the opening to less than 0.3 mm, and the step of inserting a semi-finished product thus obtained in a die and imparting a predetermined force thereto by suitable force imparting means thereby bringing the outer sheath portion of corrosion and heat resisting material into intimate contact with the corresponding portion of said core of highly heat conductive material for closing the firing end.
Claim 4
Dependent Claim
29 words
A method as claimed in claim 2, wherein said highly heat conductive material is copper and said corrosion and heat resisting material is an alloy containing nickel and chromium.
Claim 5
Dependent Claim
52 words
A method as claimed in claim 1, wherein said force applying step comprises further the step of fusing the corrosion and heat resisting material portion around a minute cavity which may be produced at the firing end so as to completely fill the cavity with the material without using any other material.
Claim 6
Dependent Claim
52 words
A method as claimed in claim 2, wherein said force applying step comprises further the step of fusing the corrosion and heat resisting material portion around a minute cavity which may be produced at the firing end so as to completely fill the cavity with the material without using any other material.
Claim 7
Dependent Claim
29 words
A method as claimed in claim 5, wherein said highly heat conductive material is copper and said corrosion and heat resisting material is an alloy containing nickel and chromium.
References Cited (Backward Citations)
US2945293A
Cited
US3119944A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1977-06-24 | 1977-12-24 | 1978-06-25 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1981-06-24 | 1981-12-24 | 1982-06-25 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1985-06-24 | 1985-12-24 | 1986-06-25 | $7700.00 | Window Closed / Lapsed |