Granted Patent
Utility
US 5,542,454 · App. 08/224,753
Free flow low energy pipe protector
Inventors:
Douglas W. Carlson, Stephen P. Simons
Patented Case
View Patent ↗
Granted: Aug 6, 1996
Filed: Apr 8, 1994
Inventors
Douglas W. Carlson
Stephen P. Simons
Assignee (at issue)
Hydril Company L.P.
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.