Issued Patents All Time
Showing 1–2 of 2 patents
| Patent # | Title | Co-Inventors | Date |
|---|---|---|---|
| 5156222 | Directional drilling tool apparatus and method | Rainer Jurgens, Joachim Oppelt, Dietmar Krehl, Dagobert Feld | 1992-10-20 |
| 4519574 | Auxiliary controlled valve disposed in a drilling string | — | 1985-05-28 |