One of the oldest and nicest exhibits of the movement archive is this, unfortunately unmarked, pocket watch movement from Ch.H.Meylan, which at least to the case can be dated back to the year 1906.
It has got a diameter of 32.3mm, which equals 14 1/3 lignes.
On many details, you can see the high quality of this movement.
Already on the base plate, you can see, that a high number of bearing rubies were used, in addition with the lever pallets and the balance ellipse, no less that 18 jewels were used, much more, than it was usual at the beginning of the 20th century.
The movement with the serial number 69669 can be assigned to the swiss manufactury Charles Henri Meylan due to the lion hallmark (which is out of focus on the photo, sorry…).
The mainspring barrel uses an (unfortunately not completely preserved) stop wheel (Maltese cross), which allows the restrict the usage of the mainspring to a defined range, in which its force is more or less constant. This leads to a better accurancy.
The classical constructed gear train with mainspring barrel (whose ratchet wheel uses a wolf teething for petter power transmission as well, as the crown wheel), directly driven minute wheel, third wheel, seconds wheel opposite to the crown and steel escape wheel was the optimum that time.
The escape wheel is beared below an own cock. Minute-, third and fourth wheel are all located below the same small bridge.
The highly polished lever with its kind of tentacles is very beautiful. These tentacles restrict the deflection of the lever and protects the delicate lever pallets and the fine teeth of the escape wheel.
The large bimetal compensation balance beats with 18000 A/h and regulates a classical swiss pallet lever movement. Of course, it is not yet secured by a shock protection.
The effective length of the hairspring with Breguet overcoil can be adjusted by a long regulator arm on a scale.
On the dial side, you see the keyless works with its yoke winding system. The setting lever, which switches by a handle between winding and time setting, is at the same time its own spring. At 2 o’clock you can see this.
|Number of jewels:||18|
Guillaume screw balance|
|Balance bearing / direction hairspring:||Counterclockwise|
|Adjust mechanism:||Long regulator arm|
|Construction type:||solid construction|
|Winding mechanism:||yoke winding system|
|Functions:||hour, minute, decentral second|
|Size:||14 1/3''' (measured: 32,3mm)|