Patent US3890518A successfully refreshed from Google Patents.
US3890518A
Expired / Lapsed
US
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Spark ignition plug
Assignee: ZF International UK Ltd
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Filing: 1973-06-01
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Granted: 1975-06-17
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Expires: 1993-06-01
Abstract
Abstract A spark ignition plug comprises an inner electrode 13 a portion 15 of which is formed from tungsten and an outer electrode 12, there being an air gap disposed between the electrodes. The tungsten is provided with a diffused surface layer 16 of oxidation resistant material.
Inventors
- 👤 Terence Leslie Tombs
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-05 15:20
CPC Classifications
H; H01; H01T; H01T13/00; H01T13/20; H01T13/39
Claims Analysis
Total Claims: 5
Claim 1
Independent Claim
44 words
A SPARK IGNITION PLUG INCLUDING AN OUTER, ANNULAR ELECTRODE, AN INNER ELECTRODE FORMED AT LEAST IN PART OF TUNGSTEN AND AN AIR GAP BETWEEN THE ELECTRODES, THE TUNGSTEN PART OF THE INNER ELECTRODE BEING PROVIDED WITH A DIFFUSED, OXIDATION RESISTANT SURFACE LAYER OF SILICON.
Claim 2
Dependent Claim
44 words
A SPARK IGNITION PLUG INCLUDING AN OUTER, ANNULAR ELECTRODE, AN INNER ELECTRODE FORMED AT LEAST IN PART OF TUNGSTEN AND AN AIR GAP BETWEEN THE ELECTRODES, THE TUNGSTEN PART OF THE INNER ELECTRODE BEING PROVIDED WITH A DIFFUSED, OXIDATION RESISTANT SURFACE LAYER OF SILICON.
Claim 3
Dependent Claim
29 words
A plug as claimed in claim 1 including a member formed from a material having a high dielectric constant interposed between the air gap and one of the electrodes.
Claim 4
Dependent Claim
18 words
A plug as claimed in claim 2 in which said member is positioned adjacent the outer annular electrode.
Claim 5
Dependent Claim
14 words
A plug as claimed in claim 2 in which the material is calcium titanate.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1978-06-16 | 1978-12-16 | 1979-06-17 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1982-06-16 | 1982-12-16 | 1983-06-17 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1986-06-16 | 1986-12-16 | 1987-06-17 | $7700.00 | Window Closed / Lapsed |