| Number | Name | Date | Kind |
|---|---|---|---|
| 1661873 | Buxbaum | Mar 1928 | |
| 2816672 | Facchini | Dec 1957 | |
| 4007993 | Schwartz | Feb 1977 |
| Entry |
|---|
| Publication "The Kee Klamp System of Pipe Construction", by Gascoigne Industrial Products, 1980 copyright. |
| Publication "Kovar Klamps", by Klamp-It Industries. |
| Publication "Hollaender Structural Pipe Fittings", by Hollaender Manuf. Co., Aug. 1982. |