| Number | Name | Date | Kind |
|---|---|---|---|
| 2257219 | Bath | Sep 1941 | |
| 2811850 | Clary | Nov 1957 | |
| 3379031 | Lewis, Jr. | Apr 1968 | |
| 3405534 | Sullivan | Oct 1968 | |
| 3538719 | Pradel | Nov 1970 | |
| 3621671 | Ullrich | Nov 1971 | |
| 3721418 | Vincent | Mar 1973 | |
| 3751935 | MacCracken et al. | Aug 1973 | |
| 3771891 | Nirenski et al. | Nov 1973 | |
| 3946529 | Chevaux | Mar 1976 | |
| 4191243 | Donzis | Mar 1980 | |
| 4394817 | Remillard | Jul 1983 | |
| 4513583 | Watt | Apr 1985 | |
| 4551985 | Kovach | Nov 1985 | |
| 4703597 | Eggemar | Nov 1987 | |
| 4782889 | Bourne | Nov 1988 | |
| 4979373 | Huppee | Dec 1990 | |
| 5027613 | Pare | Jul 1991 | |
| 5087030 | Jones | Feb 1992 | |
| 5251689 | Hakim-Elahi | Oct 1993 | |
| 5327737 | Eggemar | Jul 1994 |
| Number | Date | Country |
|---|---|---|
| 1285728 | Jul 1962 | FRX |
| 1 281 455 | Oct 1968 | DEX |
| 2 038 080 | Apr 1971 | DEX |
| 29 40 945 A1 | Apr 1981 | DEX |
| Entry |
|---|
| Popular Science Magazine, Home Technology, Phillips, William G., Heating "Hot Feet," Apr. 1998, p. 43. |