Granted Patent
Utility
US 4,755,669 · App. 07/016,014
Vacuum monitoring apparatus
Inventors:
Robert Bruce Grant, Joseph P. R. Jullien
Patented Case
View Patent ↗
Granted: Jul 5, 1988
Filed: Feb 18, 1987
Inventors
Robert Bruce Grant
Joseph P. R. Jullien
Assignee (at issue)
VG Instruments Group Limited
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.