Granted Patent
Utility
US 6,793,441 · App. 10/297,360
Tunnel waterproofing method
Inventors:
Sachio Shimizu, Keiichi Kosuge
Patented Case
View Patent ↗
Granted: Sep 21, 2004
Filed: Dec 5, 2002
Inventors
Sachio Shimizu
Keiichi Kosuge
Assignee (at issue)
W.R. Grace & Co. Conn.
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.