Granted Patent
Utility
US 4,235,109 · App. 06/058,084
Stem seat for piston and cylinder type thermal device
Inventor:
Warren G. Williamson
Patented Case
View Patent ↗
Granted: Nov 25, 1980
Filed: Jul 16, 1979
Inventor
Warren G. Williamson
Assignee (at issue)
ROBERTSHAW CONTROLS PRIVATE LIMITED
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.