Granted Patent
Utility
US 4,640,455 · App. 06/846,835
Method of making a metal seal for flanged joints and a seal made by said method
Inventors:
Lutz Grein, Gunter Matthiensen
Patented Case
View Patent ↗
Granted: Feb 3, 1987
Filed: Apr 1, 1986
Inventors
Lutz Grein
Gunter Matthiensen
Assignee (at issue)
Leybold-Heraeus GmbH
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.