Granted Patent
Utility
US 6,286,352 · App. 09/453,743
Stretch roll forming apparatus using frusto-conical rolls
Inventor:
Gerald Hackstock
Patented Case
View Patent ↗
Granted: Sep 11, 2001
Filed: Dec 2, 1999
Inventor
Gerald Hackstock
Assignee (at issue)
Pullman Industries, 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.