Number | Name | Date | Kind |
---|---|---|---|
567231 | Glauber | Sep 1896 | |
850023 | Lewis | Apr 1907 | |
925762 | Eager | Jun 1909 | |
1722676 | Parker | Jul 1929 | |
2086007 | Tompkins | Jul 1937 | |
2215318 | Bristol | Sep 1940 | |
2449754 | Seitz | Sep 1948 | |
3598157 | Farr et al. | Aug 1971 | |
4898494 | Ellis | Feb 1990 | |
5007664 | Mann | Apr 1991 | |
5027665 | Hayward | Jul 1991 | |
5141255 | Hanaoka | Aug 1992 | |
5143408 | Holtsmark | Sep 1992 |
Entry |
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Brochure of Northern Pipe Products, Fargo, North Dakota, undated but admitted to be prior art. |