Granted Patent
Utility
US 4,316,504 · App. 06/120,585
Check/relief valve for an inflatable packer system
Inventors:
Randy S. Baker, Gerald C. Eckmann
Patented Case
View Patent ↗
Granted: Feb 23, 1982
Filed: Feb 11, 1980
Inventors
Randy S. Baker
Gerald C. Eckmann
Assignee (at issue)
BJ-Hughes 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.