Granted Patent
Utility
US 4,375,834 · App. 06/276,945
Casing perforation method and apparatus
Inventor:
Donald E. Trott
Patented Case
View Patent ↗
Granted: Mar 8, 1983
Filed: Jun 24, 1981
Inventor
Donald E. Trott
Assignee (at issue)
D & D
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.