US3758139A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Connection ends on duct or conduit section
Assignee: Johns Manville Corp
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Filing: 1972-09-08
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Granted: 1973-09-11
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Expires: 1992-09-08
Abstract
Abstract A method of reforming ends of tubular sheet metal duct or conduit sections having helically grooved walls so as to enable such sections to be connected in end-to-end relationship.
Inventors
- 👤 R Meserole
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-05 20:28
CPC Classifications
F; F16; F16L; F16L25/00; F16L25/10; F16L37/00; F16L37/02; F16L9/00; F16L9/02; F16L9/06; Y; Y10; Y10S; Y10S285/00; Y10S285/903
Claims Analysis
Total Claims: 3
Claim 1
Independent Claim
102 words
A tubular sheet metal duct section comprising: a. first and second end portions, said first and second end portions having generally cylindrical walls with knurled surfaces, said first end portion being of a first diameter, said second end portion having a tapered extremity of a diameter less than said first diameter to enable said tapered extremity to be received in a first end portion of another duct section and a section adjacent said tapered extremity of a diameter substantially equal to the first diameter, and b. an intermediate portion extending between said end portions, said intermediate portion having a helically corrugated wall.
Claim 2
Dependent Claim
102 words
A tubular sheet metal duct section comprising: a. first and second end portions, said first and second end portions having generally cylindrical walls with knurled surfaces, said first end portion being of a first diameter, said second end portion having a tapered extremity of a diameter less than said first diameter to enable said tapered extremity to be received in a first end portion of another duct section and a section adjacent said tapered extremity of a diameter substantially equal to the first diameter, and b. an intermediate portion extending between said end portions, said intermediate portion having a helically corrugated wall.
Claim 3
Dependent Claim
22 words
The tubular sheet metal duct section as defined in claim 1 wherein said tapered extremity has crimps therein to reduce the diameter.
References Cited (Backward Citations)
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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) | 1976-09-10 | 1977-03-12 | 1977-09-11 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-09-10 | 1981-03-12 | 1981-09-11 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-09-10 | 1985-03-12 | 1985-09-11 | $7700.00 | Window Closed / Lapsed |