Granted Patent
Utility
US 4,821,646 · App. 07/116,707
Delay initiator for blasting
Inventors:
Donald C. True, Raymond L. Carriere
Patented Case
View Patent ↗
Granted: Apr 18, 1989
Filed: Nov 4, 1987
Inventors
Donald C. True
Raymond L. Carriere
Assignee (at issue)
CXA LTD./CXA LTEE
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.