Patent US3575780A successfully refreshed from Google Patents.
US3575780A
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US
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Surface for playing fields
Assignee: BASF SE
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Filing: 1969-05-06
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Granted: 1971-04-20
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Expires: 1989-05-06
Abstract
Abstract SPECIAL SURFACES FOR PLAYING FIELDS COMPRISING AN UPPER LAYER, A1, A MIDDLE LAYER A2 AND A LOWER LAYER A3, LAYERS A1 AND A3 CONSISTING OF A THERMOPLASTIC MOLDING MATERIAL HAVING A SPECIAL COMPOSITION. THE LAYERS A1 AND A3 ARE WEBS OR BOARDS HAVING PARALLEL RIBS ON ONE SIDE, AND THE LAYER A2 IS A STRIP OR SHEET OF STEEL OR PLASTICS MATERIAL. THE RIBS ON THE LAYERS A1 AND A3 ARE IN CONTACT WITH THE MIDDLE LAYER A2 AND ARRANGED IN SUCH A WAY THAT THEY ARE STAGGERED AT EQUAL DISTANCES IN REALTION TO EACH OTHER.
Inventors
- 👤 Hans-Georg Trieschmann
- 👤 Leo Unterstenhoefer
- 👤 Siegfried Maier
- 👤 Heinz Berbner
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-07 13:12
CPC Classifications
E; E01; E01C; E01C13/00; E01C13/04; E01C13/045; E04; E04F; E04F15/00; E04F15/22; Y; Y10; Y10S; Y10S273/00; Y10S273/04; Y10T; Y10T428/00; Y10T428/24; Y10T428/24174; Y10T428/24479; Y10T428/24562; Y10T428/26; Y10T428/30; Y10T428/31504; Y10T428/31678
Claims Analysis
Total Claims: 0
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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) | 1974-04-19 | 1974-10-19 | 1975-04-20 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1978-04-19 | 1978-10-19 | 1979-04-20 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1982-04-19 | 1982-10-19 | 1983-04-20 | $7700.00 | Window Closed / Lapsed |