Granted Patent
Utility
US 5,752,787 · App. 08/783,569
Base of a manhole having a canal-bed liner
Inventor:
Julian P. Trangsrud
Patented Case
View Patent ↗
Granted: May 19, 1998
Filed: Jan 15, 1997
Inventor
Julian P. Trangsrud
Assignee (at issue)
Royal Anchor Systems, 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.