Granted Patent
Utility
US 5,738,140 · App. 08/773,779
Adjustable height extension stem and valve box assembly
Inventor:
Jerry T. Mann
Patented Case
View Patent ↗
Granted: Apr 14, 1998
Filed: Dec 26, 1996
Inventor
Jerry T. Mann
Assignee (at issue)
AMERICAN Cast Iron Pipe Company
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.