Granted Patent
Utility
US 4,258,853 · App. 05/899,433
Extensible boom for cranes
Inventors:
Stephen H. Gill, Theodore B. Hogg
Patented Case
View Patent ↗
Granted: Mar 31, 1981
Filed: Apr 24, 1978
Inventors
Stephen H. Gill
Theodore B. Hogg
Assignee (at issue)
Caterpillar Tractor Co.
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.