Granted Patent
Utility
US 4,452,311 · App. 06/423,151
Equalizing means for well tools
Inventors:
Steven C. Speegle, Michael B. Vinzant, Vinson D. Sullivan
Patented Case
View Patent ↗
Granted: Jun 5, 1984
Filed: Sep 24, 1982
Inventors
Steven C. Speegle
Michael B. Vinzant
Vinson D. Sullivan
Assignee (at issue)
Otis Engineering Corporation
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.