Precision Electronic Levels

I'm interested in the electronic levels mentioned in the thread "Surface plate maintenance (19 March 2009 et seq), specifically the Talyval from Taylor Hobson. This is the Mahr unit. I've been trying to find the original patents (long expired), but have struck out, probably because the US Patent Office only has searchable text back to 1976. I think it was Jon Elson who mentioned these patents.

What I have found is US Patents 4,023,413 and 5,022,264 from Wyler AG is Switzerland, a competitor. This is capacitive, not inductive like the Talyval unit.

Anyway, does anyone know the patent numbers, or the inventors name? Or an article or book reference? I have found only a number of truncated references or descriptions, but nothing with real meat on it.

Thanks,

Joe Gwinn

Reply to
Joseph Gwinn
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Search assignees for "Taylor Hobson"?

Reply to
Richard J Kinch

Reply to
Charles Lessig

Google patents goes back more than 100 years. Go to google search to more, even more, and the light bulb icon. You can search by words, date, names or number. It is free and you can print it out. OCR gets a few titles garbled but it is quite good. Charlie

Reply to
Charles Lessig

I have used Google Patents before, but had a lot of trouble with OCR-induced garbles defeating search. But it's worth a try, as the USPTO search only goes back to 1976.

I did search on "taylor hobson", "rank", "federal products", "mahr", and so on both as patent assignees and on Google. Complicated corporate history here.

The only possible inventor name I've found so far is "Richard E Reason" who is named in a book on instrumentation as the brain behind other Taylor Hobson mechanical sensors at that time. But no hits at the USPTO.

One of those books also cited a book in German as the reference on the Taylval. I've requested the book, and will see if my schoolboy German is up to the task. Actually, the references the book cites may be sufficient, and many will be in English.

Joe Gwinn

Reply to
Joseph Gwinn

Only thing I know is that the original Talyvel was made in the early

1960's, to guess from the appearace of the unit.

But, the technology is not real complex. You need a pair of opposed, well-matched proximity sensors that are not subject to differential drift. You suspend a very light platform from insanely tiny wires. I suspect it has an aluminum vane that hangs between magnets for damping. The display box reads the difference between the two sensors. Now that I've seen the inside of one, I'll bet I could make one myself that would actually work. Of course, making it work as WELL as the Talyvel, even under various slants on the cross-axis, is not so easy.

Jon

Reply to
Jon Elson

I gather that the Talyvel Clinometers went through a number of generations, and the latest generation was built differently than you describe, although it is still pretty simple. The current generation is numbered 5, it appears.

Google for "The Electronic Level ­ Device of Many Uses" by GEORGE J. SCHUETZ, Director of Precision Gages, Mahr Federal Inc., Providence, Rhode Island. The drawing he gives is what is in the textbooks as the Talyvel.

The current Talyvel5 from Mahr has a different diagram, but this may be an oversimplification of Schuetz's diagram: search for "talyvel_5.pdf" .

Research continues.

Joe Gwinn

Reply to
Joseph Gwinn

the same basic principle is used in aircraft gyro heading instruments to detect angular deflection and provide feedback for flight directors and autopilots.

John

Reply to
John

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