Granted Patent
Utility
US 4,880,058 · App. 07/194,132
Stage cementing valve
Inventors:
Hiram E. Lindsey, Jr., Richard Adams
Patented Case
View Patent ↗
Granted: Nov 14, 1989
Filed: May 16, 1988
Inventors
Hiram E. Lindsey, Jr.
Richard Adams
Assignee (at issue)
Lindsey Completion Systems, Inc.
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.