Patent US3708867A successfully refreshed from Google Patents.
US3708867A
Expired / Lapsed
US
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Method of connecting duct or conduit sections
Assignee: Johns Manville Corp
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Filing: 1970-11-12
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Granted: 1973-01-09
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Expires: 1990-11-12
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
2026-11-08 07:18
CPC Classifications
F; F16; F16L; F16L25/00; F16L25/10; F16L9/00; F16L9/02; F16L9/06; Y; Y10; Y10T; Y10T29/00; Y10T29/49; Y10T29/49826; Y10T29/49945
Claims Analysis
Total Claims: 4
Claim 1
Independent Claim
108 words
A method of establishing a connection between tubular sheet metal duct sections having helically corrugated walls by reforming ends of the duct sections to enable the duct sections to be connected end-to-end comprising: a. at least partially removing the helical corrugations in the walls at ends of the sections by knurling the walls to at least partially collapse the helical corrugations and define knurled but generally cylindrical sleeve portions, b. tapering an outer extremity of one of said cylindrical sleeve portions to provide a tapered portion, and c. inserting the tapered portion on one section into the cylindrical sleeve portion of another section for establishing a connection therebetween.
Claim 2
Independent Claim
108 words
A method of establishing a connection between tubular sheet metal duct sections having helically corrugated walls by reforming ends of the duct sections to enable the duct sections to be connected end-to-end comprising: a. at least partially removing the helical corrugations in the walls at ends of the sections by knurling the walls to at least partially collapse the helical corrugations and define knurled but generally cylindrical sleeve portions, b. tapering an outer extremity of one of said cylindrical sleeve portions to provide a tapered portion, and c. inserting the tapered portion on one section into the cylindrical sleeve portion of another section for establishing a connection therebetween.
Claim 3
Dependent Claim
15 words
The method of claim 1 comprising: passing the walls between rollers to knurl the walls.
Claim 4
Dependent Claim
21 words
The method of claim 1 comprising: crimping the outer extremity of one of said cylindrical sleeve portions to effect the taper.
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) | 1976-01-09 | 1976-07-10 | 1977-01-09 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-01-09 | 1980-07-10 | 1981-01-09 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-01-09 | 1984-07-10 | 1985-01-09 | $7700.00 | Window Closed / Lapsed |