Granted Patent
Utility
US 4,664,561 · App. 06/895,705
Combined resin-mechanical mine roof bolt anchor
Inventor:
Jerry E. Frease
Patented Case
View Patent ↗
Granted: May 12, 1987
Filed: Aug 12, 1986
Inventor
Jerry E. Frease
Assignee (at issue)
The Eastern 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.