Granted Patent
Utility
US 4,502,901 · App. 06/543,174
Manufacture of gypsum board from FGD gypsum
Inventor:
Edward A. Burkard
Patented Case
View Patent ↗
Granted: Mar 5, 1985
Filed: Oct 19, 1983
Inventor
Edward A. Burkard
Assignee (at issue)
National Gypsum Company
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.