Double and quadruple tourbillons Tourbillon

greubel forsey double tourbillon technique, example of won 2011 international chronometry competition held horological museum in le locle

robert greubel , stephen forsey launched brand greubel forsey in 2004 introduction of double tourbillon 30° (dt30). both men had been working since 1992 @ renaud & papi, developed complicated watch movements. double tourbillon 30° features 1 tourbillon carriage rotating once per minute , inclined @ 30°, inside carriage rotating every 4 minutes.

in 2005, greubel forsey presented quadruple tourbillon à différentiel (qdt), using 2 double-tourbillons working independently. spherical differential connects 4 rotating carriages, distributing torque between 2 wheels rotating @ different speeds.