Granted Patent
Utility
US 4,386,486 · App. 06/253,592
Cover for concrete voids of lifting inserts
Inventors:
Neil L. Holt, William Gillis OLSEN
Patented Case
View Patent ↗
Granted: Jun 7, 1983
Filed: Apr 13, 1981
Inventors
Neil L. Holt
William Gillis OLSEN
Assignee (at issue)
Burke, 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.