Granted Patent
Utility
US 6,209,440 · App. 09/284,328
Hydraulic double telescopic prop
Inventors:
Friedrich Wilhelm Dannehl, Werner Reinelt
Patented Case
View Patent ↗
Granted: Apr 3, 2001
Filed: Apr 12, 1999
Inventors
Friedrich Wilhelm Dannehl
Werner Reinelt
Assignee (at issue)
DBT Deutsche Bergbau-Technik 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.