Issued Patents 1989
Showing 1–2 of 2 patents
| Patent # | Title | Co-Inventors | Date |
|---|---|---|---|
| 4819336 | Method of determining the orientation of a surveying instrument in a borehole | — | 1989-04-11 |
| 4802150 | Mud pressure control system with magnetic torque transfer | Michael K. Russell | 1989-01-31 |