Granted Patent
Utility
US 4,934,828 · App. 07/362,696
Apparatus for mixing viscous materials
Inventor:
Robert Allen Janssen
Patented Case
View Patent ↗
Granted: Jun 19, 1990
Filed: Jun 7, 1989
Inventor
Robert Allen Janssen
Assignee (at issue)
Ciba-Geigy
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.