Issued Patents 1989
Showing 1–2 of 2 patents
| Patent # | Title | Co-Inventors | Date |
|---|---|---|---|
| 4870319 | Spark plug with creepage spark gap | Walter Benedikt, Werner Herden, Siegbert Schwab | 1989-09-26 |
| 4798991 | Surface-gap spark plug for internal combustion engines | Walter Benedikt, Gerhard Heess, Werner Herden, Karl-Hermann Friese, Helmut Reum +1 more | 1989-01-17 |