Granted Patent
Utility
US 4,434,860 · App. 06/326,470
Hoist pull down system for blast hole drill
Inventor:
Bruce Deyo
Patented Case
View Patent ↗
Granted: Mar 6, 1984
Filed: Dec 2, 1981
Inventor
Bruce Deyo
Assignee (at issue)
Dresser Industries, 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.