Issued Patents 1989
Showing 1–3 of 3 patents
| Patent # | Title | Co-Inventors | Date |
|---|---|---|---|
| 4873048 | Method for the formation of a hole in a plastic pipe | — | 1989-10-10 |
| 4867928 | Apparatus and a method for the production of ribbed pipes | Ingemar Carlsson | 1989-09-19 |
| 4865797 | Method and an apparatus for the extrusion of plastic pipes | — | 1989-09-12 |