Method and apparatus for controlling the thickness of a lamina of a coextruded laminate
US4514812A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Sep 27, 1982 |
| Grant date | Apr 30, 1985 |
| Priority date | — |
| Expiry date | Sep 27, 2002 |
Classification
- Technology area (CPC B)Performing Operations; Transporting
- CPC primaryB29C2948/92952
- WIPO fieldOther special machines
- WIPO sectorMechanical engineering
Abstract
A method and apparatus for controlling the average thickness (T.sub.1) of a film lamina of thermoplastic, dielectric material having a known density (D.sub.1) and coextruded at a variable extrusion rate with a foam lamina of similar thermoplastic material having a thickness (T.sub.2) and the density of (D.sub.2) to form a thermoplastic laminate is disclosed. The apparatus comprises a first gauge for sensing the thickness of the laminate and for providing a caliper signal (C) corresponding to the thickness sensed and a second gauge for sensing the mass/unit-area of the laminate and for providing a mass signal (M) corresponding to the mass/unit-area sensed. The apparatus further comprises a third gauge for sensing a response to the dielectric material and its distribution in the laminate and for providing a dielectric signal (W) corresponding to the response sensed. The apparatus also comprises a computer connected to the first, second and third gauges and responsive to successive sets of signals comprising the caliper signal (C), the mass signal (M) and the dielectric signal (W) for calculating the thickness (T.sub.1) of the film lamina according to a specific formula and for compar…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.