Granted Patent
Utility
US 4,865,489 · App. 07/229,699
Mine roof anchor having adjustable resin retaining washer
Inventors:
John C. Stankus, Eugene H. Stewart, Glen S. Grissinger
Patented Case
View Patent ↗
Granted: Sep 12, 1989
Filed: Aug 8, 1988
Inventors
John C. Stankus
Eugene H. Stewart
Glen S. Grissinger
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.