Sonceboz ES 54

 
Sonceboz ES 54

Sonceboz ES 54

Description

Somewhere around 1975, Sonceboz launched a series of simple, Roskopf-inspired pillar movements, some of them with a pallet lever escapement, some of them, like the one here, with a pin lever escapement.

The base plate of this 12 ligne movement, which is stamped with “5400” and thus gives an indication for the caliber number, is well made, nickel plated and equipped with ruby bearings on all important positions.

base plate

base plate

The gear train reminds of a Roskopf movement, not only because of the missing center minute wheel, but because of the hands, which are driven on the dial side by a gear, which is connected with a slipping clutch to the mainspring barrel. Unlike on a real Roskopf movement, only the cannon pinion engages with the wheel on mainspring barrel, but not the hour wheel, and so a reduction wheel for the hour pinion is required.

mainspring barrel with slipping clutch

mainspring barrel with slipping clutch

The gear train is contemporarily modern, with a second wheel, driven by the mainspring barrel, followed by third wheel, directly driven center seconds wheel and finally the steel escape wheel.

gear train

gear train

As escapement, the caliber ES 54 uses a pin pallet escapement.

side view of the gear train

side view of the gear train

The balance, of course screw-less, beats slowly with 18000 A/h and can be regulated only with the hairspring key directly.

balance

balance

On the specimen shown here, no shock protection of the balance wheel is used, because the slanted arms of the balance should absorb shocks.

This principle was made popular several decades ago by Wyler, under the term “Incaflex”.

empty dial side

empty dial side

On the yet empty dial side, you see besides the yoke winding system how the slipping clutch mounted driving wheel of the mainspring barrel will engage with the cannon pinion.

A bit odd, and probably due to the “magical” number of 17 jewels, which had to be reached, are the two non-detachable cap jewels for the lever axle and the axle of the escape wheel and mainly the bearing ruby for the change wheel, at position 7:30 near the center of the movement.

Technically, a ruby bearing for such a slowly turning wheel is not really useful, but for marketing purposes, of course, it is.

dial side with cannon pinion and change wheel

dial side with cannon pinion and change wheel

As on a normal lever movement and not like on a Roskopf movement, the hour wheel is driven by an own change wheel and not by the mainspring barrel.

calender mechanism

calender mechanism

The calendar mechanism is very simple - a 12 teeth switching wheel engages with the 6 teeth star wheel of the hour wheel and thus revolves once a day.

cover calendar mechanism

cover calendar mechanism

The (in the specimen shown here most probably incomplete) calendar mechanism is secured by a cover, which bears the spring, which is responsible for the snapping of the date ring.

Sonceboz ES 54: Dial side

Sonceboz ES 54: Dial side

Technical data

Manufacturer:Sonceboz
Caliber:ES 54
Size:12''' (measured: 26,4mm)
Height:4,90mm
A/h:18000
Number of jewels:17
Escapement:Pin lever
Balance types: monometallic anular balance (two legs)
Shock protection(s): Incaflex
Balance bearing / direction hairspring:Clockwise
Moveable stud:no
Adjust mechanism:Hairspring key
Construction:
  • lever
  • escape wheel, seconds wheel, third wheel, large driving wheel, mainspring barrel
Construction type:pillar construction
Winding mechanism:yoke winding system
Setting lever spring:1 hole(s)
Features:
  • SCD (direct center seconds)
  • QG (date indication (aperture))
Inventory number:21037

Usage gallery

Etor gents watch

Etor gents watch

This movement and watch is a kind donation from Lars Schröder to the movement archive. Thank you very much for your great support!

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