06.14
Following on from their Calibre 360 chronograph movement shown at Baselworld in 2005, and the Monaco V4 movement shown last year, TAG Heuer unveiled another innovative concept for Baselworld 2010. The concept movement- called the Pendulum – is the first mechanical movement ever made for luxury watches that does away with the traditional spiral hairspring.
The Traditional Hairspring
The hairspring has been around since 1675 when it was created by Christiaan Huygens as a regulator for the transmission of stored energy in the mechanical movement. A spiral hairspring has essentially remained the only device used to give the torque required for the oscillation of the balance wheel and to regulate its frequency. And it has its limitations….
TAG set out to overcome the commonly accepted design limitations of the hairspring such as – the material it’s made of means it’s affected by variations in temperature and its mass that means it can be affected by the pull of gravity. In addition, inaccuracies in timekeeping occur due to the difference between the hairspring’s centre of gravity and it geometric centre. The second part of the challenge TAG set for themselves was to keep the movement entirely mechanical which meant they could not use electronics to take the place of a mechanical hairspring.
So what was TAG Heuer’s innovative solution?
TAG Heuer replaced the hairspring with a virtual spring that uses magnets to create a harmonic oscillator. The four magnets create a magnetic field that is controlled by geometric calculations. The result is the torque required for the balance wheel. TAG Heuer say that the oscillating period of the Pendulum movement is extremely stable and because of that, it makes a very accurate timekeeping movement. The movement effectively overcomes the inherent disadvantages of the traditional hairspring. And the magnet in the movement is fully mechanical requiring no electronics for their operation so they can produce power consistently for years and years.
When will see the Pendulum movement in a TAG Heuer watch?
One of the disadvantages of the hairspring that TAG haven’t been able to overcome yet with the Pendulum movement is that the magnets are affected by temperature. They admit that it may take a number of years before they can overcome this problem. Even if they do overcome it, TAG believe it is unlikely that Pendulum movements will replace the hairspring in their mainstream models anytime in the near future. The movement could however be used in high end limited edition timepieces.
At Baselworld, TAG Heuer showed off the Pendulum movement by putting it in a Grand Carrera case where the movement could be seen through an opening in the watch dial. Don’t ask the price however as it’s not for sale!














