Issued Patents 1989
Showing 1–1 of 1 patents
| Patent # | Title | Co-Inventors | Date |
|---|---|---|---|
| 4834193 | Earth boring apparatus and method with control valve | Curtis E. Leitko, Jr., Michael R. Wasson, Gerald A. Stangl | 1989-05-30 |
Showing 1–1 of 1 patents
| Patent # | Title | Co-Inventors | Date |
|---|---|---|---|
| 4834193 | Earth boring apparatus and method with control valve | Curtis E. Leitko, Jr., Michael R. Wasson, Gerald A. Stangl | 1989-05-30 |