US3568290A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method of making rackets having metal frames
Assignee: Dunlop Co Ltd
•
Filing: 1969-01-21
•
Granted: 1971-03-09
•
Expires: 1989-01-21
Abstract
Abstract AN IMPROVED METHOD FOR THE MANUFACTURE OF METAL FRAMES FOR BADMINTON, TENNIS AND OTHER GAMES RACKETS HAVING FLANGED APERTURES FOR THE STRINGS THEREOF, STARTING FROM A METAL TUBE HAVING AN 0.2 PROOF STRESS NOT EXCEEDING 30 TONS/SQUARE INCH, MAXIMUM STRESS NOT EXCEEDING 55 TONS/SQUARE INCH AND AN ELONGATION ON 2 INCHES OF NOT LESS THAN 25%. AFTER THE FLANGED APERTURES HAVE BEEN FORMED IN THE TUBE AND THE LATTER BENT INTO THE SHAPE OF THE RACKET FRAME, THE FRAME IS SUBJECTED TO A HARDENING PROCESS TO GIVE THE METAL A 0.2% PROOF STRESS AND A MAXIMUM STRESS EACH NOT LESS THAN 70 TONS/SQUARE INCH AND AN ELONGATION OF 2 INCHES OF NOT MORE THAN 15%.
Inventors
- 👤 William C Carlton
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-27 08:08
CPC Classifications
A; A63; A63B; A63B49/00; A63B49/02; A63B49/12; A63B49/022; A63B60/00; A63B60/02; Y; Y10; Y10T; Y10T29/00; Y10T29/49; Y10T29/4981
Claims Analysis
Total Claims: 0
No claims parsed yet. Click Sync Now above to re-index claims from Google Patents.
References Cited (Backward Citations)
No citation records indexed.
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 |