Granted Patent
Utility
US 4,457,681 · App. 06/274,132
Volume ratio control means for axial flow helical screw type compressor
Inventor:
Milton W. Garland
Patented Case
View Patent ↗
Granted: Jul 3, 1984
Filed: Jun 16, 1981
Inventor
Milton W. Garland
Assignee (at issue)
Frick Company
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.