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Jeambrun 23C

Jeambrun 23CJeambrun 23C

Description

The Jeambrun 23C is one of the last french cylinder movements and was made probably in the 1940ies. With its brige shape and the stripes decoration is appears quite modern, but technically it was already out of date, when it was made.

 base platebase plate

Even when the Jeambrun 23C was probably quite cheap at that time, its execution with a non-pillar construction and bearing rubies for balance and escapement wheel weren't usual for low-end movements at that time.

gear traingear train

The gear train is typical for a cylinder movement: The non shock-protected annular balance beats slowly with 18000 A/h, and its cylinder controls the flat cylinder wheel with its sharp teeth, which is located beyond an own cock.

That wheel are following fourth wheel (for the subseconds indication a "6 o'clock"), second wheel and the center minute wheel, all directly driven.

side view of the gear trainside view of the gear train

The advantage of a cylinder movement over a lever movement is, that not only one critical part (the lever) is saved, but due to the much larger fourth wheel, one transmission step less is used, so there's no need for a third wheel.

The disadvantage (and the reason, why those movements are obsolet) ist, that the precision is pretty bad since the sharp teeth of the cylinder wheel always stay in contact with the metal cylinder of the balance, preventing the balance from swinging freely. And additionally, this construction is very prone to magnetism.

Jeambrun 23C dial sideJeambrun 23C dial side

On the dial side, there's only a rocking bar winding mechanism with a very simple ratchet, which consists only of a spring, that intervenes directly with the teeth of the mainspring barrel.

 

 Technical data

ManufacturerJeambrun
Caliber23C
Number of jewels7
Escapementcylinder
BalanceNickel
Shock protection(s)none
Balance cock directionclockwise
Hairspring studfixed
Regulator typeLong regulator arm
Movement constructionCenter second pinion
Fourth wheel, Third wheel, Center wheel
Mainspring barrel
Construction typesolid construction
Winding mechanismRocking bar
Setting lever spring3 holes
Featuress
FunctionsHour, minute, small second
Beats per hour18000
Size101/2''' (measured: 23,2 mm)
Image in Flume Werksucher K1 -
Jeambrun 23CJeambrunJeambrun23C10 1/2'''Jeambrun 23C7 Jewels, 10 1/2''', 18000 A/h, s
Factsheet

 

Usage gallery

anonymous mens' watch around 1940anonymous mens' watch around 1940