Granted Patent
Utility
US 6,440,171 · App. 09/795,611
Double D key locking prosthesis
Inventors:
Robert L. Doubler, John E. Hammill, Sr.
Patented Case
View Patent ↗
Granted: Aug 27, 2002
Filed: Feb 27, 2001
Inventors
Robert L. Doubler
John E. Hammill, Sr.
Assignee (at issue)
Hammill Manuf. Co.
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.