Granted Patent
Utility
US 4,548,443 · App. 06/627,354
Tunnel boring machine
Inventor:
John Turner
Patented Case
View Patent ↗
Granted: Oct 22, 1985
Filed: Jul 3, 1984
Inventor
John Turner
Assignee (at issue)
Robbins, 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.