US3792694A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Spark plug safety shield
Assignee: STITT SPARK PLUG Co
•
Filing: 1972-03-30
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Granted: 1974-02-19
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Expires: 1992-03-30
Abstract
Abstract A flame and explosion preventive safety shield for detachable securement to the head block of an internal combustion engine in surrounding and encasing relation to each spark plug to provide a structural flame barrier between the spark plug and its high tension lead and the ambient atmosphere surrounding the engine. The safety shield incorporates a spark coil and a secondary lead for supplying high voltage current to the spark plug and one or more fine mesh wire screens arranged to form a heat sink-type flame barrier around the spark plug and the high voltage secondary lead of the spark coil to thereby isolate the spark plug and its high voltage lead from a potentially combustible atmosphere surrounding the engine.
Inventors
- 👤 A Brenholts
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-03 06:27
CPC Classifications
F; F02; F02P; F02P11/00; H; H01; H01T; H01T13/00; H01T13/02; H01T13/06
Claims Analysis
Total Claims: 6
Claim 1
Independent Claim
141 words
In combination with an internal combustion engine having a head block, a spark plug removably carried in said block and an ignition circuit for controlling operation of said engine; a fire and explosion-preventive safety shield comprising: a. a rigid frame detachably connected with the head block of said engine adjacent said spark plug; b. a spark coil carried by said frame in spaced relation to said spark plug and having a high voltage lead extending to and detachably engaging the electrode terminal of said spark plug; and c. a relatively fine mesh wire screen carried by said frame in relatively spaced, but encasing, relation to said spArk plug and the high voltage lead of said spark coil and defining a substantially uninterrupted flame and spark-confining, heat sink barrier around said spark plug and the high voltage lead of said spark coil.
Claim 2
Dependent Claim
141 words
In combination with an internal combustion engine having a head block, a spark plug removably carried in said block and an ignition circuit for controlling operation of said engine; a fire and explosion-preventive safety shield comprising: a. a rigid frame detachably connected with the head block of said engine adjacent said spark plug; b. a spark coil carried by said frame in spaced relation to said spark plug and having a high voltage lead extending to and detachably engaging the electrode terminal of said spark plug; and c. a relatively fine mesh wire screen carried by said frame in relatively spaced, but encasing, relation to said spArk plug and the high voltage lead of said spark coil and defining a substantially uninterrupted flame and spark-confining, heat sink barrier around said spark plug and the high voltage lead of said spark coil.
Claim 3
Dependent Claim
61 words
The combination defined in claim 1, wherein said frame, said screen and said spark coil comprise a unitary structure for quick detachment from the head block of said engine, and the high voltage lead of said coil comprises a substantially rigid rod extending from said coil interiorly of said screen for electrical engagement with the electrode terminal of said spark plug.
Claim 4
Dependent Claim
30 words
The combination defined in claim 1, wherein said frame, said screen and said spark coil comprise a unitary, dome-like structure disposed in relatively spaced, encasing relation to said spark plug.
Claim 5
Dependent Claim
27 words
The combination defined in claim 1, including a second relatively fine mesh wire screen carried by said frame in relatively spaced apart relation to said first-named screen.
Claim 6
Dependent Claim
58 words
The combination defined in claim 1, including a normally closed thermally-responsive switch means carried by said safety shield and having a remotely extending conductor for electrical connection with the ignition circuit of said engine, said switch means being operable in response to a given high temperature at said safety shield to interrupt the ignition circuit of said engine.
References Cited (Backward Citations)
US1376845A
Cited
US2149027A
Cited
FR707421A
Cited
US1956805A
Cited
US2231845A
Cited
US2423728A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1977-02-18 | 1977-08-20 | 1978-02-19 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1981-02-18 | 1981-08-20 | 1982-02-19 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1985-02-18 | 1985-08-20 | 1986-02-19 | $7700.00 | Window Closed / Lapsed |