Granted Patent
Utility
US 5,489,187 · App. 08/300,995
Impeller pump with vaned backplate for clearing debris
Inventor:
Robert B. Ray
Patented Case
View Patent ↗
Granted: Feb 6, 1996
Filed: Sep 6, 1994
Inventor
Robert B. Ray
Assignee (at issue)
Roper Industries, Ltd.
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.