Granted Patent
Utility
US 4,742,773 · App. 06/914,785
Blasting signal transmission tube delay unit
Inventors:
Stephen W. Bartholomew, Daniel C. Rontey, William J. Necker, Craig F. Adams
Patented Case
View Patent ↗
Granted: May 10, 1988
Filed: Oct 3, 1986
Inventors
Stephen W. Bartholomew
Daniel C. Rontey
William J. Necker
Craig F. Adams
Assignee (at issue)
The Ensign-Bickford 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.