Issued Patents All Time
Showing 1–11 of 11 patents
| Patent # | Title | Co-Inventors | Date |
|---|---|---|---|
| 6481033 | Multiple module mattress system with depressions accomodating inserts of differing firmness | — | 2002-11-19 |
| 6192538 | Modular mattress system with a removable liquid filled insert | — | 2001-02-27 |
| 5568659 | Mattress having integrated thermal layer for reflecting body heat | — | 1996-10-29 |
| D341052 | Cushion-like mattress coverlet | — | 1993-11-09 |
| 5092006 | Non-electrical reversible thermal cushion for a mattress or other body support surface | — | 1992-03-03 |
| 4771491 | Reinforced wall soft side waterbed | Donald W. Keefer | 1988-09-20 |
| 4715076 | Waterbed motion reduction and hydraulic enhancement system | Donald W. Keefer | 1987-12-29 |
| 4597120 | Waterbed utilizing dual fluid-filled mattresses and having improved surface continuity | Donald W. Keefer | 1986-07-01 |
| 4506397 | Waterbed construction | Donald W. Keefer | 1985-03-26 |
| 4204289 | Waterbed mattress | — | 1980-05-27 |
| 4192031 | Waterbed mattress | — | 1980-03-11 |