Granted Patent
Utility
US 5,112,933 · App. 07/686,102
Ether-based polyurethane elevator sheave liner-polyurethane-urea made from polyether urethane prepolymer chain extended with polyester/diamine blend
Inventors:
Hugh J. O'Donnell, Vincent J. Gajewski
Patented Case
View Patent ↗
Granted: May 12, 1992
Filed: Apr 16, 1991
Inventors
Hugh J. O'Donnell
Vincent J. Gajewski
Assignee (at issue)
OTIS ELEVATOR COMPANY
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.