Granted Patent
Utility
US 4,246,973 · App. 05/871,289
Controls for hydraulic percussion drill
Inventor:
James R. Mayer
Patented Case
View Patent ↗
Granted: Jan 27, 1981
Filed: Jan 23, 1978
Inventor
James R. Mayer
Assignee (at issue)
Cooper Industries Holdings
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.