The alarm stop wheel also acts as the click in a regular watch preventing the mainspring from unwinding. When fully wound the missing teeth in the stop wheel allow the arbor/mainspring to be wound further to power the going train. Under the ratchet wheel is the alarm stop wheel which controls the release of power when the alarm is triggered. When winding the watch the first four complete revolutions of the barrel arbor set up the power source for the alarm. In operation, the crown at 3 winds the mainspring and sets the time and the crown at 4 is used to set the alarm time and to enable/disable the alarm. The calibre also has an uncommon dial aperture showing the alarm state green for on, red for off. 230 is an unusual alarm calibre as it only has a single mainspring barrel powering both the alarm and the going train. As you can see above, the ratchet wheel screw had sheared off inside the barrel arbor and the ratchet wheel was rattling around inside the case. The watch arrived in non-running condition and the reason was immediately obvious. 230, a 21 jewel, manually wound alarm calibre with a beat rate of 18,000 bph. … and under the screwdown outer caseback is a sounding plate with a pin mounted on the inside which is struck by the alarm hammer, causing the plate to resonate when the alarm is ringing. Turning the watch over the caseback is unusual as it has a number of holes in it, effectively creating an echo chamber for the alarm…
1475 powered Manager model, making the Centinela something of a rarity. Introduced in 1954 the Centinela had a production run of just 2 years before being replaced by the less complicated, A.Schild Cal. The watch in this post is something of a ground breaker too as it was Fortis’ first ever alarm watch. Probably best known for their modern Flieger and aviation inspired chronograph watches, Fortis have an interesting vintage history which included working with English watchmaker John Harwood on the development and release of the first ever automatic watch in 1926, developing the first waterproof alarm chronometer in 1956 and the first Swiss made plastic cased watch, the Flipper, in 1967.
It’s been a while since I’ve written about an alarm watch on the blog, so let’s have a look at this Fortis Centinela.įortis was founded in 1912 in Grenchen by Walter Vogt who had developed his watchmaking skills whilst working for Eterna.
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