US3568288A
Expired / Lapsed
US
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Apparatus and method for making finned tubing
Assignee: FALLS MACHINE CO
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Filing: 1968-07-12
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Granted: 1971-03-09
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Expires: 1988-07-12
Abstract
Abstract METHOD AND MEANS HELICALLY WINDS METAL FIN RIBBON EDGEWISE ABOUT A ROTATING, AXIALLY ADVANCING TUBE INTO TIGHT PRESSURE ENGAGEMENT OF INNER EDGE PORTION OF RIBBON, WHILE SIMULTANEOUSLY TAPERING AND ELONGATING RIBBON TO PROGRESSIVELY OUTWARDLY INCREASING EXTENTS TOWARDS REQUISITE MAXIMUM ELONGATION AT OUTER PORTION OF FIN RIB- BON. HELICAL FIN SECURED TO TUBE AS BY TENSIONED RECEPTION OF INNER FIN EDGE AND CRIMPING TUBE STOCK AGAINST INNER PORTIONS OF FIN RIBBON, OR OTHERWISE ATTACHING INNER PORTIONS OF FIN RIBBON TIGHTLY AGAINST TUBE.
Inventors
- 👤 Arvid C K Nihlen
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-24 05:34
CPC Classifications
B; B21; B21C; B21C37/00; B21C37/06; B21C37/15; B21C37/22; B21C37/26; Y; Y10; Y10T; Y10T29/00; Y10T29/49; Y10T29/4935; Y10T29/49377; Y10T29/49378; Y10T29/49382; Y10T29/53; Y10T29/53113; Y10T29/53122
Claims Analysis
Total Claims: 0
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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) | 1974-03-08 | 1974-09-07 | 1975-03-09 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1978-03-08 | 1978-09-07 | 1979-03-09 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1982-03-08 | 1982-09-07 | 1983-03-09 | $7700.00 | Window Closed / Lapsed |