| Number | Name | Date | Kind |
|---|---|---|---|
| 2772800 | Brady | Dec 1956 | |
| 3015402 | Norton et al. | Jan 1962 | |
| 3272364 | Mindrum et al. | Sep 1966 | |
| 4029229 | Hobson | Jun 1977 | |
| 4936732 | Naab et al. | Jun 1990 |
| Number | Date | Country |
|---|---|---|
| 0235784 | Apr 1985 | EPX |
| 1059353 | Jun 1959 | DEX |
| 1882477 | Sep 1963 | DEX |
| 1919085 | Jul 1965 | DEX |
| 3024659 | Feb 1982 | DEX |
| 3543224 | Oct 1986 | DEX |
| 3902177 | Jun 1990 | DEX |
| 1545555 | May 1979 | GBX |
| Entry |
|---|
| Soviet Inventions Illustrated of Feb. 22, 1984. |
| Containerrumschlag Derwent Publications Ltd. DE-Z: Fordern und Heben 37, 1987 Nr. 12, S. 892 FIGS. 7,9. |
| European Search Report of Mar. 21, 1990. |