| Number | Name | Date | Kind |
|---|---|---|---|
| 3602870 | Willard | Aug 1971 | |
| 3609847 | Engler | Oct 1971 | |
| 3616497 | Esposito, Jr. | Nov 1971 | |
| 3629912 | Klopp | Dec 1971 | |
| 3914007 | Seidler | Oct 1975 | |
| 4040697 | Ramsay | Aug 1977 | |
| 4055800 | Fisk et al. | Oct 1977 |
| Entry |
|---|
| "A Simple and Adaptable Form of Electrical Contact", by W. P. White, Scientific American, p. 140, Feb. 11, 1911. |