Granted Patent
Utility
US 6,742,564 · App. 10/165,005
Spring force safety locking system for sectional doors
Inventor:
David Martin
Patented Case
View Patent ↗
Granted: Jun 1, 2004
Filed: Jun 7, 2002
Inventor
David Martin
Assignee (at issue)
Martin Door Manufacturing, 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.