Issued Patents All Time
| Patent # | Title | Co-Inventors | Date |
|---|---|---|---|
| 7510006 | Pipe running tool having a cement path | Daniel Juhasz, George I. Boyadjieff, Brian L. Eidem, Hans van Rijzingen, Herman M. Kamphorst +3 more | 2009-03-31 |
| 6915857 | Non-seize material attachment for a drill slip system | Johannes Wilhelmus Henricus van Rijzingen, David Mason | 2005-07-12 |
| 6776070 | Iron roughneck | David Mason, George I. Boyadjieff, Johannes Kamp | 2004-08-17 |