| Number | Name | Date | Kind |
|---|---|---|---|
| 3833199 | Frake | Sep 1974 | |
| 4227672 | Cunningham | Oct 1980 | |
| 4722541 | Carlson et al. | Feb 1988 | |
| 5174909 | Ward | Dec 1992 |
| Number | Date | Country |
|---|---|---|
| 216404 | May 1924 | GBX |
| 259037 | Oct 1926 | GBX |
| Entry |
|---|
| "Pilaster Forming", Symons Corporation, Mar. 1988. |
| "Pilaster Forms", Symons Corporation, undated. |