Granted Patent
Utility
US 4,474,381 · App. 06/489,495
Metal pipe joint seal ring with port to control erosion
Inventors:
Robert Lee Wilkins, Eugene J. Cegielski, James P. McEver, Edward J. Szymczak
Patented Case
View Patent ↗
Granted: Oct 2, 1984
Filed: Apr 28, 1983
Inventors
Robert Lee Wilkins
Eugene J. Cegielski
James P. McEver
Edward J. Szymczak
Assignee (at issue)
Cameron Iron Works, 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.