Granted Patent
Utility
US 4,245,637 · App. 05/923,346
Shutoff valve sleeve
Inventor:
Robert L. Nichols
Patented Case
View Patent ↗
Granted: Jan 20, 1981
Filed: Jul 10, 1978
Inventor
Robert L. Nichols
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.