Issued Patents 1989
Showing 1–2 of 2 patents
| Patent # | Title | Co-Inventors | Date |
|---|---|---|---|
| 4867669 | Safety air plug and extrusion apparatus using same | Steven E. Spence, Robert F. Shamet | 1989-09-19 |
| 4846648 | Triple-wall foam coextrusion apparatus | Steven E. Spence, Robert F. Shamet, Horst Eigruber | 1989-07-11 |