Granted Patent
Utility
US 4,413,634 · App. 06/259,240
Low volume change detection
Inventor:
Robert J. Marchbanks
Patented Case
View Patent ↗
Granted: Nov 8, 1983
Filed: Apr 30, 1981
Inventor
Robert J. Marchbanks
Assignee (at issue)
NATIONAL RESEARCH DEVELOPMENT 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.