Granted Patent
Utility
US 4,244,588 · App. 06/127,999
Shear seal assembly
Inventor:
Stewart A. Langewisch
Patented Case
View Patent ↗
Granted: Jan 13, 1981
Filed: Nov 5, 1979
Inventor
Stewart A. Langewisch
Assignee (at issue)
Caterpillar Tractor Co.
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.