Granted Patent
Utility
US 4,558,994 · App. 06/627,328
Dual stage air compressor
Inventors:
Frank J. Viola, Erwin L. Schaub, Bernard C. Sharp, Raymond J. Evans
Patented Case
View Patent ↗
Granted: Dec 17, 1985
Filed: Jul 2, 1984
Inventors
Frank J. Viola
Erwin L. Schaub
Bernard C. Sharp
Raymond J. Evans
Assignee (at issue)
Parker-Hannifin 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.