Granted Patent
Utility
US 5,340,199 · App. 07/946,338
Method and machine for excavating drifts, tunnels, stopes, caverns or the like
Inventors:
Wilfried Piefenbrink, Walter Weber, Hermann Hamburger
Patented Case
View Patent ↗
Granted: Aug 23, 1994
Filed: Nov 6, 1992
Inventors
Wilfried Piefenbrink
Walter Weber
Hermann Hamburger
Assignees (at issue)
HDRK Mining Research Limited
Wirth Maschinen-und Bohrgerate-Fabrik GmbH
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.