Granted Patent
Utility
US 4,403,448 · App. 06/331,974
Apparatus for closing and sealing a doorway
Inventor:
M. Kenneth Lesher
Patented Case
View Patent ↗
Granted: Sep 13, 1983
Filed: Dec 18, 1981
Inventor
M. Kenneth Lesher
Assignee (at issue)
Alco Standard Corporation
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.