Issued Patents All Time
Showing 1–2 of 2 patents
| Patent # | Title | Co-Inventors | Date |
|---|---|---|---|
| 4478015 | Cable sling arrangement for pivoting a drilling mast and drawworks elevator to a raised or reclined position in relation to a substructure support and method of cable sling string up | John J. Grisaffi | 1984-10-23 |
| 4269009 | Low lift, elevatable high floor drilling mast and substructure arrangement therefor | — | 1981-05-26 |