Granted Patent
Utility
US 4,134,781 · App. 05/793,397
Method for controlling warp in the manufacture of corrugated paperboard
Inventors:
Ronald Carstens, William J. Butcher
Patented Case
View Patent ↗
Granted: Jan 16, 1979
Filed: May 3, 1977
Inventors
Ronald Carstens
William J. Butcher
Assignee (at issue)
Key Chemicals, 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.