| Number | Name | Date | Kind |
|---|---|---|---|
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| 4360034 | Davila et al. | Nov 1982 | A |
| 4589433 | Abe | May 1986 | A |
| 4620559 | Childers et al. | Nov 1986 | A |
| 5097934 | Quinlan, Jr. | Mar 1992 | A |
| 5123873 | Rasmussen | Jun 1992 | A |
| 5647469 | Yamagishi et al. | Jul 1997 | A |
| 5980089 | Weis | Nov 1999 | A |
| 6155398 | Sagady | Dec 2000 | A |
| 6179704 | Suzuki | Jan 2001 | B1 |
| Entry |
|---|
| Pepperl+Fuchs Group, http://www.pepperl-fuchs.com.* |
| Schan Electric Corp., http://www.schanelecsz.com/m12m18.html. |