Granted Patent
Utility
US 4,799,862 · App. 07/073,823
Impellers
Inventors:
John F. Davidson, Keshavan Niranjan, Aniruddha B. Pandit
Patented Case
View Patent ↗
Granted: Jan 24, 1989
Filed: Jul 15, 1987
Inventors
John F. Davidson
Keshavan Niranjan
Aniruddha B. Pandit
Assignee (at issue)
NATIONAL RESEARCH DEVELOPMENT CORPORATION
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.