Patent US3759534A successfully refreshed from Google Patents.
US3759534A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Apex seal for rotary piston engine
Assignee: Nippon Piston Ring Co Ltd
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Filing: 1971-10-21
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Granted: 1973-09-18
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Expires: 1991-10-21
Abstract
Abstract An apex seal for a rotary piston engine is so constructed as to have a head portion with a circular sliding surface. It is made of a metal preferably cast iron, and has a base portion for supporting the head portion, which is made of a heat resistant light metal alloy, synthetic resin, or non-metallic material.
Inventors
- 👤 H Sakamaki
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-07 17:38
CPC Classifications
F; F01; F01C; F01C19/00; F01C19/005; Y; Y10; Y10S; Y10S277/00; Y10S277/935; Y10S277/936; Y10S277/938; Y10S277/939; Y10S277/94
Claims Analysis
Total Claims: 2
Claim 1
Independent Claim
55 words
An apex seal for a rotary piston engine in the form of a composite bar, said bar comprising a radially outer cast iron head portion having a rounded sliding surface and a bonded rectangular base portion of low specific gravity of one material selected from the group consisting of carbon, aluminum alloy, and magnesium alloy.
Claim 2
Dependent Claim
55 words
An apex seal for a rotary piston engine in the form of a composite bar, said bar comprising a radially outer cast iron head portion having a rounded sliding surface and a bonded rectangular base portion of low specific gravity of one material selected from the group consisting of carbon, aluminum alloy, and magnesium alloy.
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) | 1976-09-17 | 1977-03-19 | 1977-09-18 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-09-17 | 1981-03-19 | 1981-09-18 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-09-17 | 1985-03-19 | 1985-09-18 | $7700.00 | Window Closed / Lapsed |