Granted Patent
Utility
US 4,253,452 · App. 06/042,092
Ear plug assembly
Inventors:
William Robert Powers, III, William Lotter
Patented Case
View Patent ↗
Granted: Mar 3, 1981
Filed: May 24, 1979
Inventors
William Robert Powers, III
William Lotter
Assignee (at issue)
Specialty Composites, LLC
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.