Granted Patent
Utility
US 4,581,828 · App. 06/737,772
Spirit level
Inventors:
Milton E. Handler, Richard Sylvan, Michael Peterson
Patented Case
View Patent ↗
Granted: Apr 15, 1986
Filed: May 29, 1985
Inventors
Milton E. Handler
Richard Sylvan
Michael Peterson
Assignee (at issue)
The Hirsh Company
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.