Granted Patent
Utility
US 4,258,750 · App. 05/960,248
Labyrinth trim valve
Inventors:
Ira H. Schnall, John A. Brighton
Patented Case
View Patent ↗
Granted: Mar 31, 1981
Filed: Nov 13, 1978
Inventors
Ira H. Schnall
John A. Brighton
Assignee (at issue)
Copes-Vulcan, 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.