The 5 1⁄2 ligne ladies’ watch form movement Kasper 1120, whose origins date back to the mid 1950ies, is one of the smallest form movement with center second and additionally even one of the very few ladies’ watch form movements with center seconds at all.
It exact release date cannot be determined, it was probably in the mid 1960ies. Unlike its predecessor, the caliber 1100 beats already with contemporarily fast 21600 A/h.
The base plate of this 17-jewels movement shows a speciality: All important bearings contain rubies, except center minute wheel and mainspring barrel. This is pretty usual, but the fact, that the change wheel on the dial side is ruby-beared is really odd. No idea, what’s the reason for that unusual detail.
We have the classical gear train here with directly driven center minute wheel, followed by the third wheel, seconds wheel and escape wheel. The third wheel is a double one, the lower gear interferes with the seconds wheel, the upper one drives (no visible in the photo) the center second wheel.
In the side view, you can see the double third wheel.
The screw-less anular balance, which beats with 21600 A/h, is beared in two Incabloc shock protections and regulates a traditional swiss pallet lever movement. There’s no regulator arm, the precise frequency has to be fine-tuned with the hairspring key directly.
Escape wheel, seconds whee and minute wheel are beared below the lower gear train bridge, the minute wheel has got a ruby bearing only here and not on the dial side.
The double executed third wheel and the center seconds arbor and beared under a second bridge, which sits on top of the gear bridge and is locked with a single screw only. You can easily spot the bearing for the screw between the two rubies of escape wheel and seconds wheel.
The dial side looks like almost all dial sides of 5 1⁄2 ligne form movements: On top the Incabloc bearing of the balance, one the left the cutouts for the escape wheel, which makes it easy to oil the output pallet. Down is the rather large mainspring barrel cutout and on the right the yoke winding system.
|Number of jewels:||17|
Nickel anular balance|
|Balance bearing / direction hairspring:||Counterclockwise|
|Adjust mechanism:||Hairspring key|
|Construction type:||solid construction|
|Winding mechanism:||yoke winding system|
|Setting lever spring:||3 hole(s)|
|Functions:||hour, minute, second|
|Size:||5 1/2''' (measured: 13,0 x 15,1mm)|
Flume: K3 78|