Granted Patent
Utility
US 4,350,754 · App. 06/273,039
Blocked development restrainers
Inventors:
James R. Bartels-Keith, Anthony J. Puttick
Patented Case
View Patent ↗
Granted: Sep 21, 1982
Filed: Jun 12, 1981
Inventors
James R. Bartels-Keith
Anthony J. Puttick
Assignee (at issue)
Polaroid 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.