Die for the extrusion of material in tube form
US4298325A · kind A · utility
Inventor
Key dates
| Filing date | Mar 24, 1980 |
| Grant date | Nov 3, 1981 |
| Priority date | — |
| Expiry date | Mar 24, 2000 |
Classification
- Technology area (CPC B)Performing Operations; Transporting
- CPC primaryB29C48/32
- WIPO fieldOther special machines
- WIPO sectorMechanical engineering
Abstract
A die for the extrusion of a tube of plastic polymer consists of at least two coaxially mounted die parts forming one or more annular die gaps between them from which the tube is extruded. The die parts have two respective axial cylindrical surfaces. There is provided between these surfaces an annular member of material of higher coefficient of expansion than the material from which the die parts are made. As the die becomes heated this annular member also becomes heated and its additional expansion causes its outside diameter to expand and its inside diameter to contract into forcible engagement with the surfaces thereby stabilizing the radial gap between the die lips.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.