Method of making internally cross-ribbed plastics material structure
US4521368A · kind A · utility
6Cited by
9References
9Claims
0Family size
Assignee
Inventors
Key dates
| Filing date | Jul 1, 1983 |
| Grant date | Jun 4, 1985 |
| Priority date | — |
| Expiry date | Jul 1, 2003 |
Classification
- Technology area (CPC B)Performing Operations; Transporting
- CPC primaryB29C2791/007
- WIPO fieldOther special machines
- WIPO sectorMechanical engineering
Abstract
A unitary tubular product having an inner layer and an outer layer connected together by a bi-planar mesh formed of helical ribs bonded at their cross-over points is produced in a single coaxial tubular extrusion process, the structure being integrally or confluently extruded. The extruder die head has annular flow channels having closely-spaced die grooves.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.