Issued Patents All Time
Showing 1–18 of 18 patents
| Patent # | Title | Co-Inventors | Date |
|---|---|---|---|
| 11511936 | Portable tank | Darrell A. Oltman | 2022-11-29 |
| 10865040 | Portable tank | Darrell A. Oltman | 2020-12-15 |
| 9657855 | Combination flow control valve and reverse flow check valve | Darrell A. Oltman | 2017-05-23 |
| 8985145 | Combination flow control valve and reverse flow check valve | Darrell A. Oltman | 2015-03-24 |
| 8829373 | Three-axis acceleration switch array | Luke J. Currano, Collin R. Becker, Gabriel L. Smith, Brian Isaacson | 2014-09-09 |
| 8312889 | Combination flow control valve and reverse flow check valve | Darrell A. Oltman, Thomas P. O'Connell | 2012-11-20 |
| 6215978 | Position-sensitive educational product | Steven L. Ruzic, Patrick Rome | 2001-04-10 |
| 5161977 | School subject learning aid and tutor | — | 1992-11-10 |
| D320255 | Portable bulk storage tank | David L. Waltke | 1991-09-24 |
| 5018752 | Shaft seal | — | 1991-05-28 |
| 4932551 | Composite tank assembly | David L. Waltke | 1990-06-12 |
| 4921126 | Liquid supply system utilizing stacked tanks | David L. Waltke | 1990-05-01 |
| D305353 | Tank | — | 1990-01-02 |
| 4890814 | Discharge valve with handle lock | — | 1990-01-02 |
| D300074 | Combined pallet and containers therefor | — | 1989-02-28 |
| 4785965 | Apparatus for storing pressurized materials | — | 1988-11-22 |
| D298450 | Tank | David L. Waltke, Gary Gibson | 1988-11-08 |
| 4648521 | Composite metal and plastic tank | David L. Waltke, Gary Gibson | 1987-03-10 |