Granted Patent
Utility
US 4,148,111 · App. 05/856,133
Temperature compensating hydraulic door closer
Inventor:
Sideny Lieberman
Patented Case
View Patent ↗
Granted: Apr 10, 1979
Filed: Nov 30, 1977
Inventor
Sideny Lieberman
Assignee (at issue)
Reading Door Closer Corp.
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.