This application is a continuation-in-part of our pending application Ser. No. 117,401, filed Jan. 31, 1980, now abandoned.
| Number | Name | Date | Kind |
|---|---|---|---|
| 3055922 | Levinson | Sep 1962 | |
| 3502700 | Krakower et al. | Mar 1970 | |
| 3721687 | Elks et al. | Mar 1973 | |
| 3992422 | Green | Nov 1976 | |
| 4041055 | Shephard et al. | Aug 1977 |
| Number | Date | Country | |
|---|---|---|---|
| Parent | 117401 | Jan 1980 |