| Number | Name | Date | Kind |
|---|---|---|---|
| 1382668 | O'Rourke | Jun 1921 | |
| 3075359 | Clark | Jan 1963 | |
| 3298155 | Byfield et al. | Jan 1967 | |
| 3466883 | Drenkel | Sep 1969 | |
| 3550344 | Maier et al. | Dec 1970 | |
| 3558124 | McMichael | Jan 1971 | |
| 3735546 | Newman | May 1973 | |
| 3863420 | Peiffer et al. | Feb 1975 | |
| 4363202 | Kenyon | Dec 1982 | |
| 4450666 | Trumbull et al. | May 1984 | |
| 4584812 | Miskolczi, Jr. | Apr 1986 |
| Entry |
|---|
| Pneumat-O-Ring International, Inc., "Expand-O-Ring" Brochure. |
| Rock Products, p. 94, Pneumat-O-Ring International, Inc. Advertisement, Apr. 1990. |