Granted Patent
Utility
US 6,237,686 · App. 09/326,053
Cementing plug
Inventors:
Robert Lawrence Ryll, Colin Reid
Patented Case
View Patent ↗
Granted: May 29, 2001
Filed: Jun 4, 1999
Inventors
Robert Lawrence Ryll
Colin Reid
Assignee (at issue)
Top Industrial, Inc.
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.