Patent US3890519A successfully refreshed from Google Patents.
US3890519A
Expired / Lapsed
US
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Spark discharge plugs
Assignee: ZF International UK Ltd
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Filing: 1973-05-30
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Granted: 1975-06-17
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Expires: 1993-05-30
Abstract
Abstract A spark discharge plug comprises an outer annular electrode and an inner electrode, the two electrodes in use being connected to a source of electric supply, an annular air gap intermediate the electrodes and a dielectric material having a high permittivity interposed between one of the electrodes and the air gap.
Inventors
- 👤 Henry James Chafer
- 👤 Stuart Graham
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-27 21:09
CPC Classifications
H; H01; H01T; H01T13/00; H01T13/52; H01T13/20; H01T13/36
Claims Analysis
Total Claims: 9
Claim 1
Independent Claim
86 words
A spark discharge plug for igniting and air/fuel mixture in an internal combustion engine and comprising an annular outer electrode, and inner electrode, an annular air gap intermediate the electrodes and an annular body of dielectric material having a permittvity of at least 50 interposed between one of the electrodes and the air gap, said body acting to ensure that when the electrodes are connected to a source of electric supply a substantial proportion of the voltage of the electric supply appears across the air gap.
Claim 2
Dependent Claim
86 words
A spark discharge plug for igniting and air/fuel mixture in an internal combustion engine and comprising an annular outer electrode, and inner electrode, an annular air gap intermediate the electrodes and an annular body of dielectric material having a permittvity of at least 50 interposed between one of the electrodes and the air gap, said body acting to ensure that when the electrodes are connected to a source of electric supply a substantial proportion of the voltage of the electric supply appears across the air gap.
Claim 3
Dependent Claim
20 words
A spark discharge plug as claimed in claim 1 in which the air gap is positioned adjacent the inner electrode.
Claim 4
Dependent Claim
17 words
A spark discharge plug as claimed in claim 2 in which said dielectric material is calcium titanate.
Claim 5
Dependent Claim
96 words
A spark discharge plug as claimed in claim 1 comprising a hollow metallic body having at one end said outer electrode, the internal surface of said outer electrode tapering inwardly towards said end of the body, a hollow insulator within the body and having an outer end surface complementary to said tapered portion of the body, means urging said surface of said insulator into engagement with the tapered portion of the body and an electrode extending with clearance through said insulator, said insulator being formed from said dielectric material and said electrode defining said inner electrode.
Claim 6
Dependent Claim
48 words
A spark discharge plug as claimed in claim 4 in which said inner electrode is mounted on a further insulator carried within the body, said further insulator having a skirt portion surrounding said first mentioned insulator and a flange having a surface in sealing engagement with the body.
Claim 7
Dependent Claim
39 words
A spark discharge plug as claimed in claim 5 including a sleeve member for retaining said further insulator in position within the body said sleeve member being retained in the body by a rolled over portion of the body.
Claim 8
Dependent Claim
18 words
A spark discharge plug as claimed in claim 6 in which said means comprises a coiled compression spring.
Claim 9
Dependent Claim
16 words
A spark discharge device as claimed in claim 7 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 |