Granted Patent
Utility
US 5,009,549 · App. 07/363,274
Expansion assembly for mine roof bolts
Inventor:
John C. Stankus
Patented Case
View Patent ↗
Granted: Apr 23, 1991
Filed: May 22, 1989
Inventor
John C. Stankus
Assignee (at issue)
Jennmar 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.