Granted Patent
Utility
US 4,984,944 · App. 07/177,187
Drill bit blade for masonry and rock drill
Inventors:
Donald C. Pennington, Jr., John D. Knox
Patented Case
View Patent ↗
Granted: Jan 15, 1991
Filed: Apr 4, 1988
Inventors
Donald C. Pennington, Jr.
John D. Knox
Assignee (at issue)
Vermont American Corporation
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.