Granted Patent
Utility
US 4,315,505 · App. 06/137,626
Tracheostomy tube with disposable inner cannula
Inventors:
Norman C. Crandall, Robert C. French
Patented Case
View Patent ↗
Granted: Feb 16, 1982
Filed: Apr 7, 1980
Inventors
Norman C. Crandall
Robert C. French
Assignee (at issue)
Shiley Incorporated
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.