Issued Patents All Time
Showing 1–2 of 2 patents
| Patent # | Title | Co-Inventors | Date |
|---|---|---|---|
| 7991554 | Method for predicting rate of penetration using bit-specific coefficients of sliding friction and mechanical efficiency as a function of confined compressive strength | William Malcolm Calhoun, Russell Thomas Ewy | 2011-08-02 |
| 7412331 | Method for predicting rate of penetration using bit-specific coefficient of sliding friction and mechanical efficiency as a function of confined compressive strength | William Malcolm Calhoun, Russell Thomas Ewy | 2008-08-12 |