Granted Patent
Utility
US 4,718,444 · App. 06/938,150
Valve seat retraction method and apparatus
Inventor:
Leon W. Boelte
Patented Case
View Patent ↗
Granted: Jan 12, 1988
Filed: Dec 4, 1986
Inventor
Leon W. Boelte
Assignee (at issue)
KF Industries, Inc.
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.