Granted Patent
Utility
US 4,227,573 · App. 05/961,139
Reinforced seal unit for pumpdown pistons or well swabs
Inventors:
Joseph L. Pearce, Thomas W. Ray, Donald F. Taylor, John H. Yonker
Patented Case
View Patent ↗
Granted: Oct 14, 1980
Filed: Nov 16, 1978
Inventors
Joseph L. Pearce
Thomas W. Ray
Donald F. Taylor
John H. Yonker
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.