Granted Patent
Utility
US 6,708,448 · App. 09/849,887
Drive unit for doors, especially elevator doors having a non-rectilinear profile
Inventor:
Roberto Zappa
Patented Case
View Patent ↗
Granted: Mar 23, 2004
Filed: May 4, 2001
Inventor
Roberto Zappa
Assignee (at issue)
Sematic Italia S.p.A.
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.