Granted Patent
Utility
US 4,016,621 · App. 05/584,375
Device and method for launching and/or retrieving pipeline scrapers
Inventors:
Maurice Slegers, John D. Muchow
Patented Case
View Patent ↗
Granted: Apr 12, 1977
Filed: Jun 6, 1975
Inventors
Maurice Slegers
John D. Muchow
Assignee (at issue)
Willis Oil Tool Co.
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.