Granted Patent
Utility
US 4,975,556 · App. 07/285,591
Butt welding machine
Inventors:
Archie Tan, Vernon R. Fencl
Patented Case
View Patent ↗
Granted: Dec 4, 1990
Filed: Dec 16, 1988
Inventors
Archie Tan
Vernon R. Fencl
Assignee (at issue)
Grotnes Metalforming Systems, 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.