Granted Patent
Utility
US 4,601,402 · App. 06/259,932
Steerable concentric ring segment supported lift crane
Inventors:
Percy R. Helm, James G. Morrow, Sr.
Patented Case
View Patent ↗
Granted: Jul 22, 1986
Filed: May 4, 1981
Inventors
Percy R. Helm
James G. Morrow, Sr.
Assignee (at issue)
The Manitowoc Company, 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.