Granted Patent
Utility
US 5,960,882 · App. 08/787,688
Dual-ended apparatus for cutting openings in lined conduits
Inventor:
Richard C. Polivka
Patented Case
View Patent ↗
Granted: Oct 5, 1999
Filed: Jan 23, 1997
Inventor
Richard C. Polivka
Assignee (at issue)
Insituform (Netherlands) B.V.
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.