Granted Patent
Utility
US 4,720,884 · App. 07/009,143
Cleaning pig with debris flushing action
Inventor:
Gene R. Ralls
Patented Case
View Patent ↗
Granted: Jan 26, 1988
Filed: Jan 29, 1987
Inventor
Gene R. Ralls
Assignee (at issue)
T.D. WILLIAMSON
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.