In the past years we have often written about the Armin Strom Mirrored Force Resonance, a wristwatch that we are especially fond of (you can read our full review here).
This model is equipped with a sophisticated dual regulator mechanism with the primary goal to increase precision and rate stability by taking advantage of the resonance phenomenon.
It utilizes two independent mainsprings, gear trains, escapements, and balances, each connected by a rack and pinion to allow fine tuning of the distance between them.
The precise adjustment of the distance between the two regulators is necessary to incite resonance, resulting in the two balances finding a concurrent rhythm in opposite directions so as to continuously average out errors for maximum accuracy.
Mechanical resonance is a physical phenomenon which can affect most objects. In fact, any object free to vibrate has its own specific vibration rate. This is called the object's natural frequency or resonant frequency and it depends on several variables, including size, shape, and composition of the object.
Due to resonance, even a relatively weak vibration in one object could drive another object to oscillate with greater amplitude when the frequency of its oscillations matches the object’s natural frequency.
An example of resonance is provided by a car engine that causes vibration in another component of the car. These vibrations occur because that component has a natural frequency equal to the frequency of the vibrations set up by the engine. The component is said to be in resonance with the engine.
Especially in seismic zones, buildings are constructed to take into account the oscillating frequencies of expected ground motion. Generally, structures are designed to resonate at frequencies which do not typically occur.
Some resonant objects have more than one resonance frequency, particularly at harmonics (multiples) of the strongest resonance. It will vibrate easily at those frequencies, and less so at other frequencies. It will "pick out" its resonance frequency from a complex excitation, such as an impulse or a wideband noise excitation.
In watchmaking only few watchmakers attempted to take advantage of this phenomenon to improve accuracy, precision and rate stability of a timepiece.
Christiaan Huygens (1629–1695), the Dutch mathematician and physicist who invented the pendulum clock, first reported the phenomenon of resonance by observing the oscillations of two pendulums hanging on a wall in close proximity.
No matter how the pendulums on these clocks began, within about a half-hour, they ended up swinging in exactly the opposite direction from each other.
Although at that time Huygens did not have the proper mathematical knowledge (differential calculus had not been invented yet) for explaining this behaviour which he described as an "odd kind of sympathy", he realized that the responsible for the phenomenon could be the small vibrations of the wooden bar on which the clocks were hanging.
At the end of the 18th century, French clockmaker Antide Janvier (1751-1835) had the idea to build two complete movements with two precision escapements and to place them close to each other, ensuring that the two pendulums were hanging from the same construction. Just as he imagined, the pendulums recovered the energy dissipated by each other and began to beat together, thus entering into resonance and enhancing precision.
Thirty years later, Abraham-Louis Breguet created his famous double pendulum clock. Resonance was used to lock the two pendulums in anti-phase, that is, swing in opposite directions. Once locked into anti-phase, each pendulum will correct errors in the other, should they occur.
More recently, François-Paul Journe decided to pay tribute to the research conducted on resonance by the great 18th century watchmakers.
In 1983, he took up the challenge with a first creation in the form of a pocket-watch, which did not yet perform according to his expectations. After fifteen more years of research and development, he was finally able to present his Chronomètre à Resonance, the first resonance wristwatch.
The movement had two completely separate gear trains leading to the twin oscillators with individual escapements.
In 2005, Beat Haldimann also took advantage of resonance to increase precision but with a different approach. In fact, for his H2 Flying Resonance the twin flying tourbillons rotating around a shared central axis were powered by just one gear train. Nonetheless, each balance had its own escapement, hence acting as separate resonant mechanical systems.
If we look at the implementation that Armin Strom introduced at the end of 2016 for the Mirrored Force Resonance model and its hand-wound Calibre ARF15, we notice two independent mainsprings, gear trains, escapements, and balances, each connected by a rack and pinion to allow fine tuning of the distance between them and brought to the front face of the watch.
The resonance clutch spring is a fundamental element of this complex mechanical system. Its shape is so sophisticated that the brand’s team, led by technical director Claude Greisler, had to create it in-house. It took two and a half years perfecting the spring, until it had the optimal form to connect Armin Strom’s two sets of oscillators.
The possibility to precisely adjust the distance between the two regulators is a fundamental feature to tune such a sophisticated system and incite resonance.
When the two balances find a concurrent rhythm in opposite directions, there are at least three main advantages: a stabilizing effect on timekeeping, a conservation of energy (think of a cyclist riding in the shadow of another cyclist in a racing situation), and a reduction of negative effects on timekeeping accuracy due to outside perturbation.
For example, an outside shock that slows one of the balances down increases the speed of the other one by the same amount; both balances will strive to get back in resonance, thereby averaging and minimizing the effects of the outside influence as they find their rhythm.
If the 48-hour power reserve has been exhausted and the movement requires to be wound again, the twin balance wheels will need approximately 10 minutes to become synchronous. In case of any outside influence in the form of shock, it takes only a few minutes for the two balances to find their resonant rhythm once again.
This behaviour is explained by the fact that the resonance clutch spring connects the balance spring studs which receive the impulses rather than the balance wheels.
While improving the watch’s overall precision, the beauty of the resonance implementation used by Armin Strom also stands in the possibility to observe this phenomenon, and admire how the two resonant regulators work in a sympathetic manner, while wearing the watch on the wrist.
This model is equipped with a sophisticated dual regulator mechanism with the primary goal to increase precision and rate stability by taking advantage of the resonance phenomenon.
It utilizes two independent mainsprings, gear trains, escapements, and balances, each connected by a rack and pinion to allow fine tuning of the distance between them.
The precise adjustment of the distance between the two regulators is necessary to incite resonance, resulting in the two balances finding a concurrent rhythm in opposite directions so as to continuously average out errors for maximum accuracy.
Mechanical resonance is a physical phenomenon which can affect most objects. In fact, any object free to vibrate has its own specific vibration rate. This is called the object's natural frequency or resonant frequency and it depends on several variables, including size, shape, and composition of the object.
Due to resonance, even a relatively weak vibration in one object could drive another object to oscillate with greater amplitude when the frequency of its oscillations matches the object’s natural frequency.
An example of resonance is provided by a car engine that causes vibration in another component of the car. These vibrations occur because that component has a natural frequency equal to the frequency of the vibrations set up by the engine. The component is said to be in resonance with the engine.
Especially in seismic zones, buildings are constructed to take into account the oscillating frequencies of expected ground motion. Generally, structures are designed to resonate at frequencies which do not typically occur.
Some resonant objects have more than one resonance frequency, particularly at harmonics (multiples) of the strongest resonance. It will vibrate easily at those frequencies, and less so at other frequencies. It will "pick out" its resonance frequency from a complex excitation, such as an impulse or a wideband noise excitation.
In watchmaking only few watchmakers attempted to take advantage of this phenomenon to improve accuracy, precision and rate stability of a timepiece.
Christiaan Huygens (1629–1695), the Dutch mathematician and physicist who invented the pendulum clock, first reported the phenomenon of resonance by observing the oscillations of two pendulums hanging on a wall in close proximity.
No matter how the pendulums on these clocks began, within about a half-hour, they ended up swinging in exactly the opposite direction from each other.
Although at that time Huygens did not have the proper mathematical knowledge (differential calculus had not been invented yet) for explaining this behaviour which he described as an "odd kind of sympathy", he realized that the responsible for the phenomenon could be the small vibrations of the wooden bar on which the clocks were hanging.
At the end of the 18th century, French clockmaker Antide Janvier (1751-1835) had the idea to build two complete movements with two precision escapements and to place them close to each other, ensuring that the two pendulums were hanging from the same construction. Just as he imagined, the pendulums recovered the energy dissipated by each other and began to beat together, thus entering into resonance and enhancing precision.
An astronomical, 3 week-going, weight-driven, "resonance" double pendulum wall regulator with two independent trains produced by Antide Javier. Image courtesy of Antique Clocks Price Guide
Thirty years later, Abraham-Louis Breguet created his famous double pendulum clock. Resonance was used to lock the two pendulums in anti-phase, that is, swing in opposite directions. Once locked into anti-phase, each pendulum will correct errors in the other, should they occur.
The Breguet No. 3671, also known as the double pendulum clock.
Made for King George IV, this clock is still in possession of the British royal family. Breguet made only two other double pendulum clocks, of which one remains in the Musée des arts et métiers in Paris and the other was burnt in the 1871 fire that destroyed the Palais des Tuileries.
Image courtesy of the Royal Collection © HM Queen Elizabeth II
Made for King George IV, this clock is still in possession of the British royal family. Breguet made only two other double pendulum clocks, of which one remains in the Musée des arts et métiers in Paris and the other was burnt in the 1871 fire that destroyed the Palais des Tuileries.
Image courtesy of the Royal Collection © HM Queen Elizabeth II
More recently, François-Paul Journe decided to pay tribute to the research conducted on resonance by the great 18th century watchmakers.
In 1983, he took up the challenge with a first creation in the form of a pocket-watch, which did not yet perform according to his expectations. After fifteen more years of research and development, he was finally able to present his Chronomètre à Resonance, the first resonance wristwatch.
The movement had two completely separate gear trains leading to the twin oscillators with individual escapements.
In 2005, Beat Haldimann also took advantage of resonance to increase precision but with a different approach. In fact, for his H2 Flying Resonance the twin flying tourbillons rotating around a shared central axis were powered by just one gear train. Nonetheless, each balance had its own escapement, hence acting as separate resonant mechanical systems.
If we look at the implementation that Armin Strom introduced at the end of 2016 for the Mirrored Force Resonance model and its hand-wound Calibre ARF15, we notice two independent mainsprings, gear trains, escapements, and balances, each connected by a rack and pinion to allow fine tuning of the distance between them and brought to the front face of the watch.
When the two balances find a concurrent rhythm in opposite directions, there are at least three main advantages: a stabilizing effect on timekeeping, a conservation of energy (think of a cyclist riding in the shadow of another cyclist in a racing situation), and a reduction of negative effects on timekeeping accuracy due to outside perturbation.
For example, an outside shock that slows one of the balances down increases the speed of the other one by the same amount; both balances will strive to get back in resonance, thereby averaging and minimizing the effects of the outside influence as they find their rhythm.
If the 48-hour power reserve has been exhausted and the movement requires to be wound again, the twin balance wheels will need approximately 10 minutes to become synchronous. In case of any outside influence in the form of shock, it takes only a few minutes for the two balances to find their resonant rhythm once again.
This behaviour is explained by the fact that the resonance clutch spring connects the balance spring studs which receive the impulses rather than the balance wheels.
While improving the watch’s overall precision, the beauty of the resonance implementation used by Armin Strom also stands in the possibility to observe this phenomenon, and admire how the two resonant regulators work in a sympathetic manner, while wearing the watch on the wrist.
