| Number | Name | Date | Kind |
|---|---|---|---|
| 2174779 | Delorme | Oct 1939 | A |
| 2874649 | Pelletier | Feb 1959 | A |
| 2937095 | Zitin | May 1960 | A |
| 3653776 | Geisel | Apr 1972 | A |
| 3850183 | Gruska | Nov 1974 | A |
| 4202879 | Shelton | May 1980 | A |
| 4291018 | Oeda et al. | Sep 1981 | A |
| D344017 | Lang et al. | Feb 1994 | S |
| 5733058 | Hofmann | Mar 1998 | A |
| 6102600 | Bedol | Aug 2000 | A |
| Entry |
|---|
| Hornung, Clarence P. Handbook of Designs and Devices, (New York: Dover Publications, Inc.. 1959). p. 152: top row, shape # 1361. |