This application is a continuation-in-part of application for U.S. letters Pat., Ser. No. 961,684 filed on Nov. 17, 1978.
Number | Name | Date | Kind |
---|---|---|---|
2727036 | McDermott | Dec 1955 | |
3650771 | Wiener et al. | Mar 1972 | |
3966988 | Wilson | Jun 1976 |
Number | Date | Country | |
---|---|---|---|
Parent | 961684 | Nov 1978 |