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View picture in original size
Fig. 1

View picture in original size
Fig. 2

View picture in original size
Fig. 3

Eterna 52

stem wind and pin or lever set alarm
sub second

18''', Dm= 41.2mm, Do= 41.9mm
H= 7.3mm
(alarm stopwork +0.4mm)
F= 0.9mm
T= 3.5mm
11/15 jewels
f = 18000 A/h
Gangreserve 38h/57h
(alarm on/off)
alarm 10...15s

Balance staff U247

Stem W1662

1.90 x 1.20 / 0.35mm

Comments about the data

909-1931 (probably longer)
open face calibre
bimetallic screw balance with 4 adjustment screws
watch and alarm driven by a single barrel
alarm wheel with setting hand beared in dial (Fig.3)
ratchet on dial side, crown mechanism with singke-arm rocker bar
crown mechanism with set lever,
back crown for alarm setting

On dial and/or alarm bell mentioned patents:
Swiss Patent 47816:
mechanism making 2...3 revolutions of the barrel arbor available for the alarm
filed 04-29-1909, Gustav Häusler (DE), transfered to Eterna
Swiss Patent 42203:
bidirectional setting of the alarm time
filed 02-11-1908, Eterna, Schild Frères & Co (CH)

only 1909: alarm setting only counterclockwise
1909-1918: alarm setting bidirectional

Example, year: signature; shock device
1918: 2008958 - 958
(11 jewels)

Not for Sale!
The movements presented in this caliber finder are not for sale. This is only a data sheet for identification and evaluation of the movement calibre, as well as for approximate dating.

bidfun-db 21.3 © 02-08-15, mtr-Ranfft

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