Granted Patent
Utility
US 5,031,691 · App. 07/600,484
Multi-lance tube cleaning system having sliding plate
Inventor:
Thomas B. Boisture
Patented Case
View Patent ↗
Granted: Jul 16, 1991
Filed: Oct 19, 1990
Inventor
Thomas B. Boisture
Assignee (at issue)
Ohmstede Mechanical Services, 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.