Granted Patent
Utility
US 4,564,544 · App. 06/556,969
Fire-resistant gypsum board
Inventors:
Edward A. Burkard, James J. Segada
Patented Case
View Patent ↗
Granted: Jan 14, 1986
Filed: Dec 1, 1983
Inventors
Edward A. Burkard
James J. Segada
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.