Granted Patent
Utility
US 4,720,929 · App. 06/829,779
Trenching device
Inventor:
Gerald E. Umberson
Patented Case
View Patent ↗
Granted: Jan 26, 1988
Filed: Feb 14, 1986
Inventor
Gerald E. Umberson
Assignee (at issue)
Capitol Trencher Corporation
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.