Patent US3921020A successfully refreshed from Google Patents.
US3921020A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Spark plug
Assignee: Individual
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Filing: 1974-11-18
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Granted: 1975-11-18
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Expires: 1994-11-18
Abstract
Abstract A spark plug in which the points are covered by a non-conducting material and in which a space between the non-conducting material constitutes the spark gap for ignition of a fuel mixture. In certain embodiments of the invention the spark plug has electrodes constructed and arranged to produce a plurality of sparks during each firing cycle of the plug.
Inventors
- 👤 Bernard Wax
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-05 13:08
CPC Classifications
H; H01; H01T; H01T13/00; H01T13/20; H01T13/39
Claims Analysis
Total Claims: 5
Claim 1
Independent Claim
92 words
A spark plug comprising, a. a core of insulating material carried by a metal shell, b. a main electrode carried by said core, c. a ground electrode connected to said shell and having an end portion spaced from an end portion of the main electrode, d. a non-conducting ceramic material covering the said end portion of the ground electrode, e. a non-conducting ceramic material covering the said end portion of the main electrode, and f. a neutral electrode covered by a non-conducting ceramic material and positioned between the main and ground electrodes.
Claim 2
Dependent Claim
92 words
A spark plug comprising, a. a core of insulating material carried by a metal shell, b. a main electrode carried by said core, c. a ground electrode connected to said shell and having an end portion spaced from an end portion of the main electrode, d. a non-conducting ceramic material covering the said end portion of the ground electrode, e. a non-conducting ceramic material covering the said end portion of the main electrode, and f. a neutral electrode covered by a non-conducting ceramic material and positioned between the main and ground electrodes.
Claim 3
Dependent Claim
65 words
A spark plug as recited in claim 1, wherein the neutral electrode is a rod lying in a plane normal to the axis of the said core, wherein the said end portion of the main electrode is spaced from one end portion of said rod, and wherein the said end portion of the ground electrode is spaced from the other end portion of said rod.
Claim 4
Dependent Claim
28 words
A spark plug as recited in claim 1, wherein the neutral electrode has a helical configuration and is positioned in a helical groove formed in the said core.
Claim 5
Dependent Claim
21 words
A spark plug as recited in claim 3, wherein the neutral electrode comprises two portions spaced apart along the said groove.
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) | 1978-11-17 | 1979-05-19 | 1979-11-18 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1982-11-17 | 1983-05-19 | 1983-11-18 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1986-11-17 | 1987-05-19 | 1987-11-18 | $7700.00 | Window Closed / Lapsed |