Granted Patent
Utility
US 5,294,253 · App. 08/056,821
Carbon black system and improved rubber stock
Inventors:
Douglas W. Carlson, William David Breach
Patented Case
View Patent ↗
Granted: Mar 15, 1994
Filed: May 3, 1993
Inventors
Douglas W. Carlson
William David Breach
Assignee (at issue)
Hydril 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.