Extrusion dies of spiral mandrel type
US4201532A · kind A · utility
Inventor
Key dates
| Filing date | Aug 2, 1978 |
| Grant date | May 6, 1980 |
| Priority date | — |
| Expiry date | Aug 2, 1998 |
Classification
- Technology area (CPC B)Performing Operations; Transporting
- CPC primaryB29C48/32
- WIPO fieldOther special machines
- WIPO sectorMechanical engineering
Abstract
In an extrusion die of the spiral mandrel type the cross holes and their respective helical channels or grooves are arranged in sets, each set including at least two cross-holes disposed one above the other in the direction of the mandrel longitudinal axis. Preferably each set includes three or four cross holes disposed one above the other. This structure permits the provision of a large number of cross holes while leaving large spaces between the sets through which other passages, such as for bubble internal cooling system pipes, can be passed. All of the channels or grooves are relieved into the melt flow passage in the die at the same plane perpendicular to the mandrel axis. Unexpectedly the structure permits desired uniformity of annular flow from the die orifice to be obtained.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.