Patent US4881500A successfully refreshed from Google Patents.
US4881500A
Expired / Lapsed
US
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Poppet valve made of ceramics
Assignee: Niterra Co Ltd
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Filing: 1988-11-22
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Granted: 1989-11-21
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Expires: 2008-11-22
Abstract
Abstract An inclined surface of a valve head extending between a valve stem and a valve seat contacting portion has an annular portion in the place intermediate between the valve steam and the valve seat contacting portion. The inclined surface is ground at the annular portion only.
Inventors
- 👤 Takio Kojima
- 👤 Masato Taniguchi
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-02 19:02
CPC Classifications
F; F01; F01L; F01L3/00; F01L3/20; Y; Y10; Y10T; Y10T29/00; Y10T29/49; Y10T29/49229; Y10T29/49298
Claims Analysis
Total Claims: 6
Claim 1
Independent Claim
73 words
A poppet valve made of ceramics, comprising: a valve head having a valve seat contacting portion; and a valve stem integral with said valve head; said valve head having an inclined surface extending between said valve head and said valve seat contacting portion; said inclined surface having an annular portion in the place intermediate between said valve stem and said valve contacting portion; said inclinded surface being ground at said annular portion only.
Claim 2
Dependent Claim
73 words
A poppet valve made of ceramics, comprising: a valve head having a valve seat contacting portion; and a valve stem integral with said valve head; said valve head having an inclined surface extending between said valve head and said valve seat contacting portion; said inclined surface having an annular portion in the place intermediate between said valve stem and said valve contacting portion; said inclinded surface being ground at said annular portion only.
Claim 3
Dependent Claim
68 words
A poppet valve as set forth in claim 1 wherein said annular portion is so shaped as to have inner and outer circumferences which are concentric with said valve head and equidistant from a circle coinciding the middle points of generatrices by which said inclined surface is generated and as to have on a generatrix the width that is 1/3 or 1/2 of the length of said generatrix.
Claim 4
Dependent Claim
26 words
A poppet valve as set forth in claim 1 wherein said annular portion is in the form of an annular recess of a part-circular cross section.
Claim 5
Dependent Claim
33 words
A poppet valve as set forth in claim 1 wherein said annular portion is in the form of a circumference of a trancated cone and formed by removing a projected portion by grinding.
Claim 6
Dependent Claim
70 words
A poppet valve as set forth in claim 3 wherein said annular portion is so shaped as to have inner and outer circumferences which are concentric with said valve head and equidistant from a circle of which radius is (R1+R2)/2 and also have the width which is (R2-R1)/2 or (R2-R1)/2, where R1 is the radius of said valve stem and R2 is the radius of said valve seat contacting portion.
References Cited (Backward Citations)
SU302901A1
Cited
DE367003C
Cited
GB190913285A
Cited
GB489384A
Cited
FR923997A
Cited
US3147747A
Cited
US3349463A
Cited
US4187807A
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JPS59185540A
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1992-11-20 | 1993-05-22 | 1993-11-21 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1996-11-20 | 1997-05-22 | 1997-11-21 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2000-11-20 | 2001-05-22 | 2001-11-21 | $7700.00 | Window Closed / Lapsed |