Issued Patents 1989
Showing 1–2 of 2 patents
| Patent # | Title | Co-Inventors | Date |
|---|---|---|---|
| 4883413 | Rotary spiral piston displacement machine having a silicon rubber biased seal | Josef Perevuznik, Fritz Spinnler | 1989-11-28 |
| 4861244 | Spiral displacement machine with concave circular arcs sealingly engaging circular steps | Roland Kolb | 1989-08-29 |