Granted Patent
Utility
US 4,131,830 · App. 05/876,004
Position control and obstruction detector apparatus for a motor-driven door operator
Inventors:
Maw H. Lee, Barry V. Prehodka
Patented Case
View Patent ↗
Granted: Dec 26, 1978
Filed: Feb 8, 1978
Inventors
Maw H. Lee
Barry V. Prehodka
Assignee (at issue)
Clopay 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.