Granted Patent
Utility
US 4,833,797 · App. 07/046,511
Trencher attachment
Inventors:
Leslie J. Slunecka, Calvin H. Hansen, Leroy B. Stumpe
Patented Case
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Granted: May 30, 1989
Filed: May 6, 1987
Inventors
Leslie J. Slunecka
Calvin H. Hansen
Leroy B. Stumpe
Assignee (at issue)
Du-Al Manufacturing Company
This patent predates the USPTO's electronic file wrapper — prosecution documents from this era exist only in the Patent Office's paper records. A certified copy of the file history can be ordered from the USPTO's paper archives.