| Number | Date | Country | Kind |
|---|---|---|---|
| 3-055852 | Feb 1991 | JPX |
| Number | Name | Date | Kind |
|---|---|---|---|
| 1087352 | Cox et al. | Feb 1914 | |
| 1133700 | Basile | Mar 1915 | |
| 1810564 | Kelemen | Jun 1931 | |
| 2541893 | Speer | Feb 1951 | |
| 2949617 | Taylor | Aug 1960 |
| Entry |
|---|
| Japanese Utility Model Provisional Publication No. 28097/1988 (63-28097). |
| Japanese Patent Provisional Publication No. 26190/1987 (62-26190). |
| Japanese Utility Model Provisional Publication No. 22297/1988 (63-22297). |