| Number | Name | Date | Kind |
|---|---|---|---|
| 2018261 | Holdsworth | Oct 1935 | A |
| 3053410 | Eaddy | Sep 1962 | A |
| 4133079 | Kriechbaum et al. | Jan 1979 | A |
| 5237726 | Gartenmann et al. | Aug 1993 | A |
| 5446946 | Leifeld | Sep 1995 | A |
| 5450656 | Ueding et al. | Sep 1995 | A |
| 5575040 | Leifeld et al. | Nov 1996 | A |
| 5829100 | Stentenbach | Nov 1998 | A |
| 5937484 | Sramek et al. | Aug 1999 | A |
| 6182425 | Ficker et al. | Feb 2001 | B1 |
| Number | Date | Country |
|---|---|---|
| 0255880 | Feb 1988 | EP |
| 0344484 | Dec 1989 | EP |
| Entry |
|---|
| Patent Abstract of Japan, Mar. 7, 1995. |
| German Patent Office Search Report, Jan. 10, 2001. |