US3767740A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method for forming table tennis balls
Assignee: Dunlop Ltd
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Filing: 1971-06-24
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Granted: 1973-10-23
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Expires: 1991-06-24
Abstract
Abstract A METHOD FOR FORMING TABLE-TENNIS BALLS FROM A LARGE NUMBER OF THERMOPLASTIC MATERIALS INCLUDING POLYVINYL CHLORIDE AND TERPOLYMER OF ACRYLONITRILE WITH BUTADIENE AND STYRENE, WHICH INCLUDES THE STEPS OF ALIGNING TWO HEMISPHERES OF A RIGID THERMOPLASTIC MATERIAL TO FORM A SPHERICAL CAVITY, SUBJECTING THE EDGES OF EACH HEMISPHERE TO A HIGH FREQUENCY, ALTERNATING ELECTRIC CURRENT TO SOFTEN AND ADHERE TOGETHER THE EDGES TO FORM A BUTT-JOINT AND FORMING A REINFORCING BEAD ON THE INSIDE SURFACE OF THE BALL AROUND THE BUTT-JOINT.
Inventors
- 👤 Hinton J Jones
- 👤 T Gray
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-28 20:35
CPC Classifications
B; B29; B29D; B29D22/00; B29D22/04; B29C; B29C51/00; B29C51/26; B29C51/266; B29C51/267; B29C65/00; B29C65/02; B29C65/04; B29C66/00; B29C66/01; B29C66/05; B29C66/10; B29C66/13; B29C66/131; B29C66/1312; B29C66/32; B29C66/328; B29C66/3282; B29C66/50; B29C66/51; B29C66/54; B29C66/70; B29C66/73; B29C66/739; B29C66/7392; B29C66/73921; B29C66/80; B29C66/81; B29C66/814; B29C66/8141; B29C66/81411; B29C66/81415; B29C66/81421; B29C66/81423; B29C66/81427; B29C66/81431; B29C66/83; B29C66/832; B29C66/8322; B29C51/10; B29C65/72; B29C66/71; B29L; B29L2031/00; B29L2031/54
Claims Analysis
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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) | 1976-10-22 | 1977-04-23 | 1977-10-23 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-10-22 | 1981-04-23 | 1981-10-23 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-10-22 | 1985-04-23 | 1985-10-23 | $7700.00 | Window Closed / Lapsed |