Granted Patent
Utility
US 4,328,147 · App. 06/202,206
Roofing asphalt formulation
Inventors:
Irving B. Chang, Robert E. Beckwith, Jr.
Patented Case
View Patent ↗
Granted: May 4, 1982
Filed: Oct 30, 1980
Inventors
Irving B. Chang
Robert E. Beckwith, Jr.
Assignee (at issue)
ALLIED CONSULTING, 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.