UMF Ruhla Caliber 24 Movement
The UMF Ruhla Caliber 24 movement was designed in the early 1960s to ensure that materials for production could be sourced from within the German Democratic Republic or from other socialist nations to fit with the ideals of communism.
Ruhla described this movement, which was the mainstay of their watch production, as a “ruggedly designed mechanical type wristwatch which has been manufactured by the VEB Uhrenwerke Ruhla”. The movements were first produced in 1963.
The UMF Ruhla caliber 24 mainspring will power the watch for approximately 28 hours continuous running. The movement was adapted by the company to be produced in order to provide several different functions. It could be fitted with a sweep second wheel, sweep second wheel and date indicator, eccentric second wheel or a moon phase indicator.
The movement has a yoke type winding mechanism, a pin-pallet escapement with a safety blade and roller. the pallet as well as the balance are located under separate cocks, this providing for easy repairability. The barrel can be easily removed separately. The tension on the spring can be relaxed from the rear of the movement.
The size of the caliber 24 movement gave the Ruhla watch factory the flexibility to use the movement in men’s, women’s and children’s watches. It was also used for pocket watches and small size alarm clocks such as the Sumatic and Midimatic clocks.
From 1973, the factory automated the production of the caliber 24 movement and applied strict quality controls to ensure consistent quality watches.
Know your Calibre 24!
Escapement: Pin Pallet Escapement with a Safety Blade and Roller
Balance Spring: Temperature Compensating
Accuracy: +240 sec/ – 120 sec/day
Number of Beats per Hour: 18,000
Diameter of movement: 24mm
Height of movement: 6mm
24 – Punktuhr using clear discs with dots to display hour and minutes
30 – no seconds
31 – small seconds
39 – Battery powered alarm clock Sumatic and Midimatic
Central second hand
Central second hand and date
Digital display for mens mechanical digital
Chronograph stop mechanism
Digital display for women’s mechanical digital