| Number | Name | Date | Kind |
|---|---|---|---|
| D229896 | Bemel | Jan 1974 | |
| D237780 | Bemel | Nov 1975 | |
| 2614349 | Barnes | Oct 1952 | |
| 3511735 | Lindley | May 1970 | |
| 3804323 | Bemel | Apr 1974 | |
| 4281762 | Hattemer | Aug 1981 | |
| 4359358 | Hattemer | Nov 1982 | |
| 4479838 | Dunsirn | Oct 1984 | |
| 4537586 | Gale et al. | Aug 1985 | |
| 4545781 | Carl et al. | Oct 1985 | |
| 4726171 | Kreager et al. | Feb 1988 | |
| 4767654 | Riggsbee | Aug 1988 | |
| 4837088 | Freedman | Jun 1989 | |
| 4909636 | De Matteis et al. | Mar 1990 | |
| 5009518 | Faltynek | Apr 1991 | |
| 5011466 | De Matteis et al. | Apr 1991 | |
| 5019436 | Schramer | May 1991 |
| Number | Date | Country |
|---|---|---|
| 2218541 | Nov 1989 | GBX |
| 2221422 | Jul 1990 | GBX |
| Entry |
|---|
| Lytel, Allan "Photoelectric Register Controls" Industrial Electronics, (Jan., 1960) pp. 38.gtoreq.42. |