Multiple-roll calendars for producing thermoplastics film
Abstract
Abstract A multiple-roll calender for producing thermoplastics films, in which, viewed in the direction of working, a penultimate roll is spaced from the roll which immediately precedes it so that for a period as it travels from said preceding roll to the penultimate roll the material being calendered is not in contact with any of the rolls, and said penultimate roll and a final roll which together define a final working gap, are provided with drive means whereby they can be driven at varying speeds independently of the other rolls. A guide roller may be provided to guide the material centrally into the final working gap or a pull-off roller or pair of pull-off rollers and a constant pressure roller may be provided to guide the material to the final working gap. Alternatively a pull-off roller and a scraper device, defining with the penultimate roll a gap which narrows in a downstream direction may be provided.
Inventors
- 👤 Gottfried Sander
Bibliographic Details
Claims Analysis
Total Claims: 5References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1980-07-25 | 1981-01-24 | 1981-07-26 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1984-07-25 | 1985-01-24 | 1985-07-26 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1988-07-25 | 1989-01-24 | 1989-07-26 | $7700.00 | Window Closed / Lapsed |