| Number | Name | Date | Kind |
|---|---|---|---|
| 2969565 | Levy | Jan 1961 | |
| 3861101 | Whisson | Jan 1975 | |
| 4056985 | Worrallo | Nov 1977 | |
| 4535577 | Tenser et al. | Aug 1985 | |
| 4682457 | Spencer | Jul 1987 |
| Number | Date | Country |
|---|---|---|
| 248701 | Jan 1963 | AUX |
| Entry |
|---|
| Foga System, 1982, 40 pages. |
| Gold Bond Building Products (undated), 7 pages. |
| Giltspur (undatd), 9 pages. |
| Rotolock (undated), 2 pages. |
| Syma Systems, Inc. (undated), 1 page. |