Granted Patent
Utility
US 4,075,715 · App. 05/742,006
Helmet having anti-lift device
Inventor:
Duane W. Cowgill
Patented Case
View Patent ↗
Granted: Feb 28, 1978
Filed: Nov 15, 1976
Inventor
Duane W. Cowgill
Assignee (at issue)
Sierra Engineering 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.