Number | Name | Date | Kind |
---|---|---|---|
1375092 | Hanson | Apr 1921 | |
1395706 | Greve | Nov 1921 | |
2979143 | Kandle | May 1958 | |
2998084 | Johnson et al. | Jul 1957 | |
3009521 | Failing | Jul 1958 | |
3126063 | Pitt et al. | Jun 1960 | |
3404741 | Gheorghe et al. | Oct 1968 | |
3464507 | Alexander et al. | Sep 1969 | |
3766991 | Brown | Oct 1973 | |
3857450 | Guier | Dec 1974 | |
3915244 | Brown | Oct 1975 | |
4126193 | Brown | Nov 1978 | |
4147215 | Hodge et al. | Apr 1979 | |
4421179 | Boyadjieff | Dec 1983 | |
4437524 | Boyadjieff | Mar 1984 | |
4449596 | Boyadjieff | May 1984 | |
4458768 | Boyadjieff | Jul 1984 | |
4610315 | Koga et al. | Sep 1986 | |
4625796 | Boyadjieff | Dec 1986 | |
4800968 | Shaw et al. | Jan 1989 | |
4865135 | Moses | Sep 1989 | |
4878546 | Shaw et al. | Nov 1989 | |
5038871 | Dinsdale | Aug 1991 | |
5107940 | Berry | Apr 1992 | |
5211251 | Woolslayer | May 1993 | |
5251709 | Richardson | Oct 1993 |
Number | Date | Country |
---|---|---|
157230 | Jan 1982 | NOX |
164557 | Mar 1983 | NOX |
Entry |
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World Oil, "DC Electric Power Swivel Can Save Time and Money", pp. 36-39, Jan. 1972. |
World Oil, "More About New Equipment", p. 257, Apr. 1979. |