Apparatus for stretching film
US4104769A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Mar 12, 1976 |
| Grant date | Aug 8, 1978 |
| Priority date | — |
| Expiry date | Mar 12, 1996 |
Classification
- Technology area (CPC B)Performing Operations; Transporting
- CPC primaryB29C2037/90
- WIPO fieldOther special machines
- WIPO sectorMechanical engineering
Abstract
An apparatus for stretching polymeric film is disclosed wherein a heating unit is located slightly above and between the parallel tracks of a tenter frame and wherein the heating unit includes an air duct with an air entrance opening and a series of apertures directed between the tenter frame tracks wherein the air duct is separated, by internal intermediate walls, into adjacent isolated zones extending parallel with the tracks of the tenter frame and wherein each isolated zone includes a heater. Air introduced into the duct is conducted through the zones where it is heated and directed through the apertures onto a web of polymeric film moving in the tenter frame prior to stretching.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.