Apparatus for sealing a hem in a moving web of film
US4721502A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Sep 8, 1986 |
| Grant date | Jan 26, 1988 |
| Priority date | — |
| Expiry date | Sep 8, 2006 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY10S493/928
- WIPO fieldOther special machines
- WIPO sectorMechanical engineering
Abstract
Apparatus for sealing a hem in a moving web of plastic film having a structure including a folding surface having a web passing on one side of the surface and an edge of the web on the other side of the surface to produce a hem in the web prior to leaving the surface. Heat sealing apparatus is supported adjacent the structure for heat sealing the hem while the web is moving and prior to the sealed hem leaving the surface. The surface is provided with an opening in alignment with the heat sealing apparatus and the heat sealing apparatus seals the hem through the opening. The heat sealing apparatus includes a plurality of heated rollers supported on one side of the structure, the rollers being adapted to extend through the opening in the surface and backup rollers are positioned on the opposite side of the structure and in alignment with the opening for cooperation with the heated rollers to engage the opposite sides of the hem for heat sealing the hem while the web is moving and prior to the sealed hem leaving the surface.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.