| Number | Date | Country | Kind |
|---|---|---|---|
| 54-26043 | Mar 1979 | JPX | |
| 54-154196 | Nov 1979 | JPX |
| Number | Name | Date | Kind |
|---|---|---|---|
| 2226589 | Smyers | Dec 1940 | |
| 2728702 | Simon et al. | Dec 1955 | |
| 3814659 | Nadeau | Jun 1974 | |
| 3940517 | De Leon | Feb 1976 | |
| 4118533 | Hipchen et al. | Oct 1978 | |
| 4121958 | Koonts | Oct 1978 | |
| 4131518 | Fromson | Dec 1978 | |
| 4148980 | Narayan | Apr 1979 | |
| 4165414 | Narayan et al. | Aug 1979 | |
| 4166164 | Cenker et al. | Aug 1979 | |
| 4205136 | Ohashi et al. | May 1980 |
| Number | Date | Country |
|---|---|---|
| 900876 | Jul 1962 | GBX |
| Entry |
|---|
| UK Patent Application GB 2,007,590 A, Published May 23, 1979, 428-313. |