Web perforating apparatus
US4691606A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Aug 1, 1986 |
| Grant date | Sep 8, 1987 |
| Priority date | — |
| Expiry date | Aug 1, 2006 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY10T83/9314
- WIPO fieldMachine tools
- WIPO sectorMechanical engineering
Abstract
As a conditioning step for wrapping a plurality of articles in a low density polyethylene shrink film, perforations are formed in the shrink film for receiving machine elements utilized in performing the wrapping operation, the film being moved continuously between a pair of infeed rolls and a pair of outfeed rolls between which a rotatable mandrel is disposed and which includes perforating knives thereon for engaging the film while the film is moved continuously, the perforating knives being disposed on the opposite side of the web from a rotatable back up roll having cavities formed therein for receiving the ends of the perforating knives in such manner that the web is maintained under tension throughout the perforating process while the backup roll serves to prevent sidewise movement of the web due to web perforating action of the perforating knives.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.