Granted Patent
Utility
US 5,575,451 · App. 08/434,042
Blowout preventer ram for coil tubing
Inventors:
Kenneth W. Colvin, William L. Carbaugh
Patented Case
View Patent ↗
Granted: Nov 19, 1996
Filed: May 2, 1995
Inventors
Kenneth W. Colvin
William L. Carbaugh
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.