Granted Patent
Utility
US 4,953,639 · App. 07/404,601
Closed loop hydraulic drill feed system
Inventors:
Jeffrey W. Hamner, George P. Schivley, Jr.
Patented Case
View Patent ↗
Granted: Sep 4, 1990
Filed: Sep 8, 1989
Inventors
Jeffrey W. Hamner
George P. Schivley, Jr.
Assignee (at issue)
Ingersoll-Rand 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.