| Number | Name | Date | Kind |
|---|---|---|---|
| D216691 | Bates et al. | Mar 1970 | |
| D220958 | Marsh | Jun 1971 | |
| D238363 | Polens | Jan 1976 | |
| D265227 | Jolley | Jun 1982 | |
| 4320004 | Schecter | Mar 1982 |
| Number | Date | Country |
|---|---|---|
| 703439 | Apr 1987 | JPX |
| 6342053 | Jan 1988 | JPX |
| 6342054 | Jan 1988 | JPX |
| Entry |
|---|
| Mechantronics Design News, vol. 8, no. 2, 1983, p. 15. |