Issued Patents All Time
Showing 1–4 of 4 patents
| Patent # | Title | Co-Inventors | Date |
|---|---|---|---|
| 6354384 | Surface effect drilling craft for obtaining continuous core samples | Wayne Newell, Donald Garrett Queen, Hubert Browning Firminger, John Andrew Grant Clarke | 2002-03-12 |
| 6129159 | Vibratory drill head apparatus | John Andrew Grant Clarke | 2000-10-10 |
| 5058688 | Convertible vibratory or rotary core drill apparatus | John Porritt | 1991-10-22 |
| 5004055 | Vibratory core drill apparatus for the recovery of soil or sediment core samples | John Porritt | 1991-04-02 |