A very rare movement from Bifora is their 7 3⁄4 ligne manual wind movement Bifora 734. It was launched in the early 1950ies and produced until 1958.
Because of its small diameter and its multi-storey construction is looks stocky and is not easy to service. The hairspring has to be positioned in a very small gap between two dials and the balance wheel.
On the base plate, you see, that all important bearings are ruby beared, except those of the minute wheel. In total, you count 15 jewels.
Like many of the better movements from the 1950ies, the Bifora 734 uses a directly driven center minute wheel.
The Bifora 734 uses the contemporary gear train with center minute wheel, third wheel, large center second wheel and escapement wheel. Due to the large diameter of the gears, it has to use a multi storey construction with large height:
The not yet shock protected screw balance beats with contemporarily slow 18000 A/h and regulates a classical pallet lever movement of swiss type. Its frequency can be adjusted by a long regulator arm with scale.
One problem of that construction is, that the two center wheel, almost reach to the escapement wheel axle, so there’s few space for fiddling in the balance, especially, since the hairspring has to be located in the small space below the two wheels above the balance wheel. Maybe that complicated and difficult to service construction was the reason, why that movement is not (more?) often to find.
On the dial side, you see the markings of the movement and the yoke winding system. Since the balance wheel is not yet shock protected, there’s just a cap jewel for its bearing.
|Number of jewels:||15|
Nickel screw balance|
|Balance bearing / direction hairspring:||Counterclockwise|
|Adjust mechanism:||Long regulator arm|
|Construction type:||solid construction|
|Winding mechanism:||yoke winding system|
|Setting lever spring:||2 hole(s)|
|Functions:||hour, minute, second|
|Size:||7 3/4''' (measured: 17,3mm)|
|Production period:||1950 - 1958|
Flume: 1952 2|