Granted Patent
Utility
US 5,794,516 · App. 08/520,801
Piston for a self-lubricating, fluid-actuated, percussive down-the-hole drill
Inventors:
Dale R. Wolfer, Leland H. Lyon
Patented Case
View Patent ↗
Granted: Aug 18, 1998
Filed: Aug 30, 1995
Inventors
Dale R. Wolfer
Leland H. Lyon
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.