Granted Patent
Utility
US 4,770,639 · App. 07/020,938
Channelized jackfield
Inventor:
Frederick L. Lau
Patented Case
View Patent ↗
Granted: Sep 13, 1988
Filed: Mar 2, 1987
Inventor
Frederick L. Lau
Assignee (at issue)
Switchcraft, Inc.
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.