Granted Patent
Utility
US 5,642,891 · App. 08/665,826
Radially expandable locking device for a pipe seal
Inventor:
William O. Skinner
Patented Case
View Patent ↗
Granted: Jul 1, 1997
Filed: Jun 19, 1996
Inventor
William O. Skinner
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.