Lorsa 237BC

Description

The 10 1/2 ligne Lorsa 237BC is a commonly constructed windup movement from France, where the base caliber was extended by a simple pointer date indication.

The execution of this movement is well, all important bearings contain rubies, so that in total, it uses the contemporarily common 15 jewels.

There are no surprises on the gear train, which consists of the mainspring barrel, that drives the center minute wheel. Following are third wheel, decentral seconds wheel with prolonged axle on the dial side at position 6 o’clock and finally the filigree steel escape wheel.

The monometallic two-leg screw balance is of course not yet shock protected. It beats with 18000 A/h, which can be adjusted with a long regulator arm and an unusual +…- scale.

As escapement, a traditional swiss pallet lever escapement is used.

On the yet empty dial side, you can see the signature of the base caliber, 237B, which itself is a modified version of the caliber Lorsa 237.

Yoke winding system (unfortunately with a broken setting lever spring on this specimen) and a partial minute dial for adjusting purposes can be seen, too.

The simple calendar mechanism is mounted with three screws onto the dial side of the base plate. The hour wheel drives a 24h wheel at position 10 o’clock, which carries a pin near its center to engage once per day with the center date wheel.

The center date wheel has got 31 teeth and carries a pointer hand on the dial. Theoretically, it could also carry a date disc, but due to the decentral seconds indication, its diameter would be quite limited.

In the lab

Technical data

Usage gallery