| Number | Name | Date | Kind |
|---|---|---|---|
| 3522943 | Swanson | Aug 1970 | |
| 3680854 | Daily et al. | Aug 1972 | |
| 3718217 | Stobb et al. | Feb 1973 | |
| 3858490 | Heisler | Jan 1975 | |
| 3982749 | Stobb | Sep 1976 | |
| 4364554 | Akers | Dec 1982 | |
| 4531343 | Wood | Jul 1985 | |
| 4588180 | Ballestrazzi et al. | May 1986 | |
| 4618136 | Pessina et al. | Oct 1986 |
| Entry |
|---|
| Advertisement, Portec Inc. Flomaster Division, Canon City, CO., perspective view enclosed and dated Jun. 7, 1966. |