Granted Patent
Utility
US 3,990,507 · App. 05/622,427
High temperature perforating apparatus
Inventor:
Roy R. Vann
Patented Case
View Patent ↗
Granted: Nov 9, 1976
Filed: Oct 14, 1975
Inventor
Roy R. Vann
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.