Christophe Claret DualTow Tourbillon Chronograph

The manufacture Christophe Claret is one of those organisations which for the last 20 years has been an undisputed force in high end watchmaking, but always undercover, making many of the movements used by the high end brands.  They are specialised in tourbillon and minute repeater movements.  Despite their vocation as a movement supplier they have at times sold watches under their own name.  This was the case at their 10th anniversary and now again for the 20th anniversary of the founding of the manufacture.

For their 20 years they have created a tourbillon chronograph dubbed the “DualTow”.  Special features include the hour and minute display on special rubber belts and the chrono coupling through differentials instead of the standard clutches.  The model was first introduced at the Basel fair this year where working prototypes where presented.  After several improvements on those prototypes since April, including using ceramic ball bearings instead of standard rubies in the belt units and optimising the return to zero of the chrono, production units will soon be leaving the manufacture. 

The day I had a chance to visit the manufacture the cases were all out of house for some final retouching, but I did get to see, photograph and touch working movements in their movement holders.  So you get an idea of the final product I have included a press photo of one of the watches seen in Basel.

First some impressions of the dial side of the movement.  Almost all of the mechanism is visible through the sapphire dial (the production of which will be seen in a later instalment).
The time of day is shown on the belts left and right.  The chrono displays of seconds, minutes and hours above the tourbillon with the chrono crown wheel that controls the functions in the middle at the top.  A major visual element is the control arms going from the crown wheel to the brakes on the differentials and the return to zero hearts.  These arms change their position according to the mode of operation as I will show below giving a somewhat spider-like effect.

Now for the dance of the spider legs,
step 1, chrono not running, reset to zero

2) Chrono running

3) Chrono stopped

4) Stopped and reset to zero

From the back of the movement we can see the gong and hammer which is sounded each time the chrono button (it is a mono-pusher) is pushed.  An impressive feat of craftsmanship is the heat bluing of the gong.  The entire length to the same color without a blemish.

As you have seen in the pictures above the return-to-zero cams have an unconventional snail shape.  The developers thought this would be advantageous causing the differentials to always turn in the same direction.  Testing has shown, however, that at the release of the reset the hands do no remain motionless and to improve that more conventional heart shaped cams have been tested and will be included in the production units.  The parts are already finished and ready to be exchanged.

The other change made since the Basel Fair introduction is the use of ceramic ball bearings in the belt assemblies instead of ruby jewels.  This allows tightening the belts more without increasing the energy required to turn the belts.  Below one of these new belt assemblies ready for installation.

All these parts are made in the manufacture Christophe Claret.  The next instalment shows some of the in-house the parts manufacturing capabilities of the manufacture seen during a tour of the plant with Mr. Claret.



This message has been edited by AnthonyTsai on 2009-06-07 09:39:27 This message has been edited by AnthonyTsai on 2009-06-11 19:11:18