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