As mentioned in connection with the Thiel chess clock, the Thiel family was expropriated after WWII in 1945 by the Russian forces and their clockworks in Ruhla and Apolda continued business under the name "Awtowelo". After the establishment of the GDR, the Russian forces handed over the enterprise to the GDR government, which continued the business under the name "VEB Klement Gottwald Uhren- und Maschinenfabrik Ruhla" or short "UMF Ruhla" (with "VEB" being the abbreviation of "Volkseigener Betrieb" = publicly owned company). In the beginning, the chess clocks produced there were still distributed using the old brand "Thiel". In 1960, however, the company developed a new clockwork, based on a variation of the caliber 6 alarm clock movement, and shortly after that a new and bigger chess clock, which was introdced under the name "Gardé", which was first presented at the 1960 Chess Olympiad in Leipzig. The UMF Ruhla Gardé became the most well known chess clock and was the last mechanical chess clock used in a world championship (1993 Nigel Short vs. Garry Kasparov). The early versions of the clock have the "UMF" or "ruhla" logo imprinted on the clock face. Later versions, which are sold until today, have a "Gardé" logo imprinted, but are less reliable as they are not equipped with the traditional inhouse movement produced by UMF Ruhla.

I managed to get hold of an extremely nice early version of the UMF Ruhla Gardé from 1964 in its original case and with the original warranty certificate and operation manual. A similar clock is depicted on the very informative and recommendable website https://ostalgieruhla.wordpress.com/ruhla-clocks/ruhla-chess-clock-schachuhr/, from which I also took some of the pictures.