Granted Patent
Utility
US 4,754,543 · App. 07/094,942
Method of making expandable and collapsible mandrel
Inventor:
Paul L. Spivy
Patented Case
View Patent ↗
Granted: Jul 5, 1988
Filed: Sep 10, 1987
Inventor
Paul L. Spivy
Assignee (at issue)
Dayco Products, LLC
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.