| Number | Name | Date | Kind |
|---|---|---|---|
| 2988036 | Mooneyhan et al. | Jun 1961 | |
| 3280997 | Pioch | Oct 1966 | |
| 3520429 | Andersson | Jul 1970 | |
| 3818852 | Lewis et al. | Jun 1974 | |
| 4049131 | Schrader et al. | Sep 1977 | |
| 4898112 | McGlew et al. | Feb 1990 | |
| 5526766 | Armstrong et al. | Jun 1996 |
| Number | Date | Country |
|---|---|---|
| 4316677 | Nov 1993 | DEX |
| Entry |
|---|
| "Shugart: Who We Are", Shugart Manufacturing, available to applicant in approximately Oct., 1997. |
| "Shugart: Barges", Shugart Manufacturing, available to applicant in approximately Oct., 1997. |