Granted Patent
Utility
US 5,911,537 · App. 08/796,867
Parabolic cover for manhole
Inventor:
Mark Pulver
Patented Case
View Patent ↗
Granted: Jun 15, 1999
Filed: Feb 6, 1997
Inventor
Mark Pulver
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.