Granted Patent
Utility
US 4,520,992 · App. 06/506,736
Slow-closing valve mechanism
Inventor:
Ralph L. Sheffer
Patented Case
View Patent ↗
Granted: Jun 4, 1985
Filed: Jun 22, 1983
Inventor
Ralph L. Sheffer
Assignee (at issue)
Adams Rite Products, 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.