Granted Patent
Utility
US 4,655,303 · App. 06/801,178
Drill bit
Inventors:
Warren J. Winters, J. Ford Brett, Tommy M. Warren
Patented Case
View Patent ↗
Granted: Apr 7, 1987
Filed: Nov 22, 1985
Inventors
Warren J. Winters
J. Ford Brett
Tommy M. Warren
Assignee (at issue)
Amoco 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.