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First I should start with a basic overview of what a sonnerie is, and what differentiates it from other striking watches. Unlike a repeater watch that strikes the time (hour, quarter, minute, and other variations) only upon demand, the sonnerie is capable of striking totally upon its own, similar to a clock. Hence sonnerie watches are often called “clock watches”. There are many different types of sonnerie watches, but they all share one similarity in that they are capable of striking at least the hours without user interaction, automatically or in-passing you might say. Some sonnerie watches called “grand sonnerie” are capable of striking not only the hours but also the quarter hour on-passing. Generally a grand sonnerie has three modes; silence (no striking), grand (striking the hours and quarter hours), and petite (striking only the hours).
The Credor Sonnerie falls into a category that reflects its Japanese heritage. It is capable of striking the hours or being silent as is the case with sonnerie watches in general. But it also has a special function called “Original” that enables it to strike three times every three hours. In other words the watch will strike dong-dong-dong at 12:00, 3:00, 6:00, and 9:00 while the other hours are silent. This Original mode is a most intriguing aspect of the Credor Sonnerie and had me baffled for a short period of time trying to figure how they accomplished the task.
At this point I’d like to move ahead with a detailed technical review of the Credor Sonnerie pointing out its unique mechanical achievements and giving you at least a basic idea of how complicated it is to produce a sonnerie watch. I’ll try to keep the message simple, but that’s not always easy in this case…
All sonnerie watches have a second barrel with mainspring “A” to power the on-passing (automatic) strike. The power from this barrel is passed in two different directions. The wheels “B” deliver power to the silent governor “C”. It is the silent governor that is quite special in this watch as it silently regulates the speed of the striking. In the other direction power is transferred via wheels “D” to the release/return mechanism “E”. Rack assembly “F” drops finger “G” onto snail “H” to signal the number of hours to be struck, and Hammer “J” strikes the bell in indication of the hours.
Another characteristic feature of a sonnerie watch is the release/return mechanism, sometimes called a ratchet. As it is that the sonnerie is capable of striking automatically there needs to be an automatic method of releasing power from the striking mainspring barrel to accomplish the striking sequence. It’s the release/return mechanism that is responsible for this automatic action and in my opinion is the heart of a sonnerie watch, not to mention the most complicated component. Finger “A” is in charge of the release function. On the left it is in a static position as it is most of every hour, and on the right it is in the act of pushing the release ratchet 25 degrees, as it does near the end of each hour, until pin “B” raises click “C” high enough to release ratchet “D” allowing the hour rack to fall (not shown yet).
In this example the release mechanism has not released yet. Rack assembly “A” is being held back, finger “B” has not contacted hour snail “C”, and a long tooth “D” of the strike ratchet (unlike the other 12 teeth “E”) is holding the strike hammer “F” away from the bell. This later holding back of the hammer prevents the hammer from striking the bell if the watch is being used during vigorous activity.
At this point, exactly on the hour, the release mechanism has released hour rack “A” allowing finger “B” to contact hour snail “C” at the 6
th lobe, or 6:00 o’clock. Also notice that the strike ratchet has rotated CW allowing 6 teeth “D” to pass past the hammer trip “E”. The “release” has taken place and the watch is ready to strike, now the “return” operation will commence…
Let the music begin. Now it’s time for the release/return mechanism to reverse roles and begin the “return” process. The hour rack has fallen onto the hour snail and the number of hours to be struck is determined, as well the hammer has been released and is now in much closer proximity to the bell (but not quite touching). At this stage the 6
th tooth “A” of the strike ratchet is about to engage the hammer trip “B” lifting the hammer until…
…their engagement is completed and the hammer falls, striking the bell to record each hour of the sequence until the hour rack and hammer have been returned to their resting positions. (Notice that the hammer has been retracted, cocked, in order to make the strike).
Of course the sonnerie can be summoned at any time by simply pushing gently on the button located along the outside of the case at the 8:00 position. But that’s almost too simple, isn’t it?
One of the most intriguing things about the Credor Sonnerie is its ability to be shifted from full sonnerie mode to original mode easily (do you remember what “Original” mode is?). With most sonnerie watches, such as a grand sonnerie, silencing the hour and/or quarter hour strike is accomplished by a series of blocking levers. But the Credor is very different in that it goes from striking every hour in the sonnerie mode to only three strikes every third hour in the Original mode. It took me two or three minutes to realize that two different snails were needed for this to be possible. It took another minute or two to comprehend that the two different snails needed to be located in exactly the same space within the watch. So it is that the Credor Sonnerie has two different snails, one for sonnerie mode and another for original mode that are located concentrically on the same shaft and shifted up or down as required.
Above we see the two snails, the sonnerie mode snail “A” with 12 steps (one for each hour), and the original mode snail “B” with 4 steps (one for each 3 hour increment) mounted on the same assembly “D”. A split fork “C” moves the snail assembly up or down on shaft “E”, as seen left and right, to facilitate the required strike mode. Is this intelligent or what?
OK, I’d love to continue this conversation and possibly write a book. But I’m sure by this time you are falling asleep or your boss is looking over your shoulder. Hopefully I’ve shed some light on the attributes of the Credor Sonnerie and the extreme complexity of sonnerie watches in general.
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