Granted Patent
Utility
US 4,328,541 · App. 06/152,884
Fail-safe digital comparator
Inventor:
Richard D. Campbell
Patented Case
View Patent ↗
Granted: May 4, 1982
Filed: May 23, 1980
Inventor
Richard D. Campbell
Assignee (at issue)
American Standard Inc.
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.