| Number | Name | Date | Kind |
|---|---|---|---|
| 2705820 | Torrence | Apr 1955 | |
| 3456410 | Olson et al. | Jul 1969 | |
| 4508301 | Nicholson | Apr 1985 | |
| 4691887 | Bessinger | Sep 1987 | |
| 4765575 | Bergl | Aug 1988 | |
| 5064158 | Brazier | Nov 1991 |
| Entry |
|---|
| Fit-All Pricing Corporation Catalog, pp. 3, 17 and 22; publication date unknown but prior to Sep. 28, 1994. |