Method for forming lines of weakness in thermoplastic
Abstract
Abstract A LINE OF WEAKNESS IS FORMED IN A SHEET OF THERMOPLASTIC WHICH HAS BEEN HEATED TO RENDER IT SOFT AND FLOWABLE BY THE DISCLOSED METHOD OF COOLING THE SURFACE OF THE HEATED SHEET BUT NOT AT THE DESIRED LINE OF WEAKNESS AND SHRINKING THE SHEET AWAY FROM SAID LINE TO REDUCE THE THICKNESS THEREAT. THE LINE OF WEAKNESS MAY BE A FOLD LINE OR A TEAR LINE, BOTH OF WHICH ARE UTILIZED IN THE DISCLOSED CARTON. A CARTON BLANK IS FORMED BY APPARATUS WHICH INCLUDES OPPOSED HEATING HEADS, OPPOSED FORMING HEADS AND A TRIMMING STATION. THE FORMING HEADS HAVE GROOVES IN THEIR SURFACES AT THE DESIRED LOCATION OF THE LINES OF WEAKNESS. MECHANISMS ARE PROVIDED FOR COOLING THE FORMING HEADS AND FOR DRAWING A VACUUM ON THE GROOVES.
Inventors
- 👤 William P Jacobson
Bibliographic Details
Claims Analysis
Total Claims: 0References 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) | 1974-05-03 | 1974-11-02 | 1975-05-04 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1978-05-03 | 1978-11-02 | 1979-05-04 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1982-05-03 | 1982-11-02 | 1983-05-04 | $7700.00 | Window Closed / Lapsed |