Granted Patent
Utility
US 4,725,215 · App. 06/946,493
Extruder with exchangeable filter for foamed plastic material
Inventors:
Udo Kreyenborg, Horst Koching
Patented Case
View Patent ↗
Granted: Feb 16, 1988
Filed: Dec 24, 1986
Inventors
Udo Kreyenborg
Horst Koching
Assignee (at issue)
KREYENBORG VERWALTUNGEN UND BETEILIGUNGEN GMBH & CO. KG
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.