Issued Patents All Time
Showing 1–13 of 13 patents
| Patent # | Title | Co-Inventors | Date |
|---|---|---|---|
| 7650901 | Ball seat leveler | — | 2010-01-26 |
| 7152615 | Earthquake actuated horizontal valve with micro switch | — | 2006-12-26 |
| 6917004 | Earthquake actuated micro switch | — | 2005-07-12 |
| RE38220 | Earthquake actuated automatic gas shutoff valve | — | 2003-08-19 |
| 6213142 | Earthquake actuated automatic gas shutoff valve | — | 2001-04-10 |
| 6112764 | Automatic safety shutoff valve | Roger P. Engdahl | 2000-09-05 |
| 5307699 | Seismic initiator for earthquake shutoff valves and the like | Roger P. Engdahl | 1994-05-03 |
| 5209454 | Automatic safety shutoff valve | Roger P. Engdahl | 1993-05-11 |
| 5144598 | Intergrating, indicating, and controlling seismometer | Roland S. McGee, Roger P. Engdahl | 1992-09-01 |
| 4694304 | Earthquake displacement recorder | — | 1987-09-15 |
| 4684958 | Seismic displacement recorder for base-isolated structures | Roger P. Engdahl | 1987-08-04 |
| 4630483 | Peak accelerograph | — | 1986-12-23 |
| 4223319 | Passive multielement shock recorder | — | 1980-09-16 |