Issued Patents 1997
Showing 1–3 of 3 patents
| Patent # | Title | Co-Inventors | Date |
|---|---|---|---|
| 5687803 | Method for reversing a ground piercing tool | Robert F. Crane, Mark D. Randa | 1997-11-18 |
| 5651639 | Method and apparatus for installation of underground pipe | Robert F. Crane | 1997-07-29 |
| 5603383 | Reversible pneumatic ground piercing tool | Robert F. Crane, Mark D. Randa | 1997-02-18 |