Issued Patents All Time
Showing 51–75 of 76 patents
| Patent # | Title | Co-Inventors | Date |
|---|---|---|---|
| 6371223 | Drill head for directional boring | Robert F. Crane | 2002-04-16 |
| 6321858 | Bit for directional drilling | Robert F. Crane | 2001-11-27 |
| 6302410 | Rod gripping jaw | Robert F. Crane | 2001-10-16 |
| 6299382 | Method for installing an underground pipe | — | 2001-10-09 |
| 6283229 | Impact device for directional boring | Robert F. Crane | 2001-09-04 |
| 6273201 | Pneumatic ground piercing tool with movable chisel head | Mark D. Randa, Robert F. Crane | 2001-08-14 |
| 6269889 | Ground piercing tool with plastic body | — | 2001-08-07 |
| 6263983 | Apparatus for directional drilling | Robert F. Crane | 2001-07-24 |
| 6260634 | Sonde housing for directional drilling | Robert F. Crane | 2001-07-17 |
| 6261027 | Portable pulling apparatus | Robert F. Crane | 2001-07-17 |
| 6171026 | Method and apparatus for replacement of pipelines | Robert F. Crane | 2001-01-09 |
| 6148935 | Joint for use in a directional boring apparatus | Robert F. Crane | 2000-11-21 |
| 5782311 | Method and apparatus for installation of underground pipes | — | 1998-07-21 |
| 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 |
| 5505270 | Reversible pneumatic ground piercing tool | — | 1996-04-09 |
| 5494116 | Pneumatic impact tool for pipe insertion | — | 1996-02-27 |
| 5487430 | Pneumatic ground-piercing tool and body therefor | Robert F. Crane, Jon A. Haas | 1996-01-30 |
| 5465797 | Pneumatic ground piercing tool with detachable head | Jon A. Haas, Robert F. Crane, Payce D. Reynolds | 1995-11-14 |
| 5440797 | Method for making a pneumatic ground piercing tool | Robert F. Crane, Jon A. Hass | 1995-08-15 |
| 5337837 | Dual-diameter pneumatic ground piercing tool | Robert F. Crane, Jon A. Haas, Payce D. Reynolds | 1994-08-16 |
| 5317953 | Neutral-centering valve control system | — | 1994-06-07 |
| 5199151 | Method for making a pneumatic ground piercing tool | Robert F. Crane, Jon A. Haas | 1993-04-06 |
| 5025868 | Pneumatic ground piercing tool | Robert F. Crane, Jon A. Haas | 1991-06-25 |