Granted Patent
Utility
US 5,647,447 · App. 08/662,725
Bit retention device for a bit and chuck assembly of a down-the-hole percussive drill
Inventor:
William Jones
Patented Case
View Patent ↗
Granted: Jul 15, 1997
Filed: Jun 10, 1996
Inventor
William Jones
Assignee (at issue)
Ingersoll-Rand Company
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.