US4487232A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Doubled-walled corrugated synthetic resin pipe
Assignee: Individual
•
Filing: 1982-06-21
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Granted: 1984-12-11
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Expires: 2002-06-21
Abstract
Abstract A double-walled corrugated synthetic resin pipe comprises a straight inner pipe, and a corrugated outer pipe surrounding the inner pipe, and joined integrally thereto. The inner pipe is formed by a spirally wound flat strip of a synthetic resin having adjoining turns joined to each other along their adjoining edges, and has a generally even outer surface. The outer pipe is formed by a spirally wound corrugated synthetic resin strip also having adjoining turns thereof joined to each other along their adjoining edges. The outer pipe has a corrugation defined by a ridge portion, a groove portion, and an intermediate portion, and the groove portion has an inner surface joined to the outer surface of the inner pipe.
Inventors
- 👤 Shiro Kanao
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-02 13:34
CPC Classifications
F; F16; F16L; F16L11/00; F16L11/14; F16L11/16; F16L11/04; F16L11/11; F16L11/118
Claims Analysis
Total Claims: 9
Claim 1
Independent Claim
165 words
A double-walled corrugated synthetic resin pipe, comprising; a straight inner pipe and a corrugated outer pipe surrounding said inner pipe and joined integrally thereto, said inner pipe being formed by a spirally wound flat strip of a synthetic resin material having adjacent turns thereof joined to each other along adjoining edges thereof, said inner pipe having an outer surface, said outer pipe being formed by a spirally wound corrugated synthetic resin strip having adjacent turns thereof joined to each other along adjoining edges thereof, said strip defining said outer pipe having a corrugation defined by a ridge portion, a pair of groove portions and intermediate portions therebetween, said groove portions each having a flat inner surface joined to said outer surface of said inner pipe and wherein said synthetic resin strips are formed of extruded polymers, such that, when assembled, the molecular structure of said polymers is oriented spirally with respect to an axis of said pipe, thereby increasing the circumferential strength of said pipe.
Claim 2
Dependent Claim
165 words
A double-walled corrugated synthetic resin pipe, comprising; a straight inner pipe and a corrugated outer pipe surrounding said inner pipe and joined integrally thereto, said inner pipe being formed by a spirally wound flat strip of a synthetic resin material having adjacent turns thereof joined to each other along adjoining edges thereof, said inner pipe having an outer surface, said outer pipe being formed by a spirally wound corrugated synthetic resin strip having adjacent turns thereof joined to each other along adjoining edges thereof, said strip defining said outer pipe having a corrugation defined by a ridge portion, a pair of groove portions and intermediate portions therebetween, said groove portions each having a flat inner surface joined to said outer surface of said inner pipe and wherein said synthetic resin strips are formed of extruded polymers, such that, when assembled, the molecular structure of said polymers is oriented spirally with respect to an axis of said pipe, thereby increasing the circumferential strength of said pipe.
Claim 3
Dependent Claim
34 words
A double-walled corrugated pipe as set forth in claim 1, wherein both said inner and outer pipes are uniform in wall thickness, said outer pipe being greater in wall thickness than said inner pipe.
Claim 4
Dependent Claim
25 words
A double-walled corrugated pipe as set forth in claim 1, wherein said ridge and groove portions are greater in wall thickness than said intermediate portion.
Claim 5
Dependent Claim
25 words
A double-walled corrugated pipe as set forth in claim 1, wherein said ridge portion is greater in wall thickness than said groove and intermediate portions.
Claim 6
Dependent Claim
20 words
A double-walled corrugated pipe as set forth in claim 4, wherein said ridge portion has a partially increased wall thickness.
Claim 7
Dependent Claim
25 words
A double-walled corrugated pipe as set forth in claim 1, wherein said groove portion is greater in wall thickness than said ridge and intermediate portions.
Claim 8
Dependent Claim
46 words
A double-walled corrugated pipe as set forth in claim 1, wherein said intermediate portion is generally greater in wall thickness than said ridge and groove portions, and has a gradually increasing wall thickness which is greater closer to said groove portion than to said ridge portion.
Claim 9
Dependent Claim
43 words
A double-walled corrugated pipe as set forth in claim 1, wherein said inner pipe has a spirally extending reduced wall thickness portion, while having an even inner surface, said groove portion of said outer pipe being joined to said reduced wall thickness portion.
References Cited (Backward Citations)
US1287945A
Cited
US2890723A
Cited
US2898941A
Cited
AT237395B
Cited
US3204666A
Cited
US3330303A
Cited
US3477891A
Cited
US4129152A
Cited
US4303104A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1987-12-11 | 1988-06-11 | 1988-12-11 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1991-12-11 | 1992-06-11 | 1992-12-11 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1995-12-11 | 1996-06-11 | 1996-12-11 | $7700.00 | Window Closed / Lapsed |