| Number | Date | Country | Kind |
|---|---|---|---|
| 8906123 | Aug 1989 | DEX |
| Number | Name | Date | Kind |
|---|---|---|---|
| 728656 | Bausch et al. | May 1903 | |
| 2439671 | Ott | Apr 1948 | |
| 2643579 | Jacoby, Jr. | Jun 1953 | |
| 2822726 | Blum | Feb 1958 | |
| 3832923 | Lossmann et al. | Sep 1974 | |
| 3913903 | Seward et al. | Oct 1975 | |
| 3975977 | Mornberg | Aug 1976 | |
| 4207790 | Endo | Jun 1980 |