In the late 1950ies, UMF Ruhla planned the superseding resp. further development of their standard pin lever movements, the UMF M54 / Thiel Start, which were too large and high, especially for ladies' watches.
This development, called “UMF Champion” or UMF M 23, was planned to be available in different versions, starting from a simple zero-jewels movement with decentral second hand up to a 23 jewel selfwinding movement. It was a 10 1/2 ligne movement with pin lever escapement.
Actually, only four different versions were produced, among them the UMF 23-32, the UMF 24-42 the other version with short axle.
1963, after only two years, the production was ceased in favor for the success movement, the caliber 24.
The caliber 23-42 has got no bearing jewels for the gears and the escapement lever, only the balance with her ruby ellipse got a double pair of bearing jewels (cap jewel and jewel bearing).
It is a simple pillar construction with a small special feature: The height of the balance wheel cock is adjustable with a screw (at 1:30 o’clock) which bends it more or less - a really simple but efficient construction.
The UMF 23-42 has the classical gear train with directly driven center minute, third wheel, fourth wheel (which could carry the decentral second center hand on the dial side - this would be caliber 23-41 then) and the escapement wheel.
The center second is indirectly driven by the third wheel. The center second and minute wheel bearing is a bent part of the top plate. The third wheel must be located in the tiny gap beween that bearing and the top plate, which makes it quite difficult to correctly place the wheels.
The non shock protected anular balance of this rather high building movements beats with 18000 A/h and regulates a conventional pin lever movement. In the side view, you can easily spot the screw for height adjustment of the balance wheel cock.
On this movement, the ratchet is on the dial side, as well, as the rocking bar winding system. The ratchet wheel is only pinned on the mainspring barrel, but it is secured by a cover with two screws - a pretty complex solution.
|Size:||10 1/2''' (measured: 23,7mm)|
|Number of jewels:||5|
Nickel anular balance|
|Balance bearing / direction hairspring:||Clockwise|
|Adjust mechanism:||Hairspring key|
|Construction type:||pillar construction|
|Winding mechanism:||rocking bar winding system|
|Setting lever spring:||2 hole(s)|
|Production period:||1961 - 1963|
Flume: K3 66|