Gravity Equal Force is the newest watch demonstrating an Armin Strom core principle: always be innovating. This watch takes the traditional mainspring barrel and turns it on its head by adding a stop-work declutch mechanism combined with automatic winding to create consistent power delivery to the balance. With a bold redesign of the movement, dial and case, Gravity Equal Force marks the launch of the new System 78 Collection, highlighting innovative watchmaking at a competitive price.
As a guiding principle, every watch that comes from the Armin Strom manufacture must include an innovation. The inspiration behind Gravity Equal Force was a desire to transmit equal force to the balance, thereby increasing the consistency of rate. Building upon the classic stop-works mechanism, Armin Strom developed an ingenious stop-works declutch system that operates inside the mainspring barrel to limit the torque delivered to the balance, providing smooth power delivery. This represents the first time a stop-works declutch mechanism has been added to an automatic winding movement.
Not content with one innovation, Armin Strom found insight in a pocket watch in need of repair from a U.S. collector, which contained a motor barrel design showing clear advantages over the standard going barrel. Inspired, the watchmakers designed a barrel operating in the reverse of a traditional mainspring barrel by driving the going train via the barrel arbour and winding the barrel housing, which both improves functionality and reduces wear.
This state-of-the-art design creates a stable, low-friction axis of rotation for the mainspring to deliver power from the barrel arbour, supported by precision jewel bearings. Though using only a portion of the mainspring by preventing it from completely unwinding, Armin Strom still achieved a power reserve of 72 hours. Wound by a unidirectionally winding micro-rotor visible from the dial, the mainspring bears a power reserve indicator on the barrel cover for reference.
With numerous small improvements to the going train and winding mechanism, the new Caliber ASB19 demonstrates Armin Strom’s commitment to continually questioning established theory and using in-house R&D to advance horological technology. Claude Greisler, the co-founder of Armin Strom, highlights the improved usability: “We have reinvented the whole functionality of an automatic watch movement to bring another level of precision and to offer our collectors more assurance for reliable daily wear.”
The new Gravity Equal Force also differs from previous models with a new off-centre dial and slimmer case with a smaller diameter. The highlight of the watch is now the triplet of bridges echoing the pocket watch inspiration behind the ASB19. The 41-millimetre case, a first for Armin Strom, should appeal to the more classically-inclined collector. The contemporary dimensions maintain the essence of Armin Strom DNA while shaping a new aesthetic that showcases a reduction to the essential. Moving to an off-centre dial, the Gravity Equal Force is more legible to maximize the user experience for discerning collectors.
The Armin Strom Gravity Equal Force is the first model of the new System 78 Collection. It features a stainless steel case and is priced at CHF 16,900.
Gravity Equal Force inspiration and development
Gravity Equal Force represents a drive to constantly improve Armin Strom watches with every model. As a creative watch brand focused on innovation, Armin Strom’s watchmakers and movement engineers routinely research and explore concepts across the horological landscape in search of ways to rethink theory and practice.
The Gravity Equal Force development began with a desire to deliver equal force to the regulating system. The result was a stop-works declutch mechanism incorporated into the barrel housing ensuring consistent power delivery to the balance and escapement.
Utilizing a Geneva wheel mounted to the barrel housing cover, the rotation of the mainspring barrel is limited to just 9 full turns out of a possible 12.5. This represents the central 72% of the mainspring’s potential torque curve, the flattest and most consistent portion. As the barrel housing unwinds around the arbour, a pin counts off the rotations on the Geneva wheel until it reaches the locked position and prevents further unwinding.
This limit keeps the power delivery to the balance as consistent as possible and the amplitude in the optimal range. Once it reaches the upper limit, the declutch mechanism guarantees the slip of the mainspring and allows the micro-rotor to turn evenly when fully wound.
A small declutch lever is attached to the Geneva wheel that marks its rotation and power reserve from full to empty. Sitting atop the barrel cover, the power reserve location will change as the watch is wound, providing some playful variation in the dial display.
The new stop-works declutch mechanism coincides with a complete reassessment of the mainspring barrel construction. When a U.S. client brought a vintage pocket watch to Armin Strom for repair, it created an opportunity to explore techniques that were common in earlier watches and update them for use in a modern movement.
Upon inspection, it was discovered that it bore a motor barrel whose barrel and winding mechanism are constructed opposite that of the standard going barrel. The standard design sees a central arbour often supported by jewel bearings rotating inside the barrel to wind the mainspring. Once fully wound, the arbour remains fixed while the mainspring pushes the barrel housing and so driving the going train.
A typical mainspring barrel doesn’t rotate in a precision jewel bearing but around the arbour, which means higher friction and less precise rotation. The Armin Strom motor barrel design reversed this so that the barrel housing stays locked after winding, allowing the well supported and more precise arbour to rotate and drive the going train.
This simple change goes against at least a century of tradition, yet, when assessed objectively, it is clear that it is a demonstrably better system as it is more precise and stable during operation of the movement. Armin Strom’s watchmakers built on this idea to create an entirely new watch that launches a brand-new collection.
The development of Caliber ASB19 sees continued improvement throughout all the components thanks to the technological advancement of the previous centuries. A new layout combined with improved geometry for the gear teeth and adjustments provides smoother operation and more robust functionality.
Armin Strom’s focus on innovation and development was kickstarted during the development of its groundbreaking Resonance Clutch Spring and has led to the watchmakers rethinking everything in an attempt to innovate where others stagnate. This isn’t limited to mechanics alone; the entirety of Armin Strom’s design aesthetic is evolving to build a new core moving forward.
The previous open-worked display has been replaced by a dial offset from the centre, providing a clear indication for the time to avoid any confusion. Retained are the visible barrel and micro-rotor, though now supported by clean geometric bridges harkening to pocket watches of the past. The entire presentation has the goal of reducing details to the essential for a cohesive package.
The previous case design has been trimmed down to create the first 41-millimetre case for Armin Strom. The iconic lip at 6 o’clock, which can be traced back to Mr. Armin Strom himself, is still present, though in a much more streamlined form. Armin Strom has taken the opportunity to improve finishing on every component throughout the movement, creating a new standard for Armin Strom calibres.
The entire philosophy of development at Armin Strom is reorganizing to focus on updating the aesthetic design to signify a new chapter for the brand. The intention is to take every opportunity to rethink watchmaking theory, improve each new watch, and take Armin Strom’s level of finishing ever higher.
System 78 – A new entry to Armin Strom
The Gravity Equal Force signals a new direction for the brand, launching the System 78 collection to replace the Single Barrel Collection. The collection is intended to be the entry point for Armin Strom, an haute horlogerie collection at a reasonable price point with impeccable finishing and constant invention.
“It’s not self-evident that we can present our watchmaking values and hunger for innovation to a broader audience. It was a big challenge to offer this level of perfection for that price” says Serge Michel, Founder of the Manufacture.
The name displays what the brand hopes to create, a System of fine watchmaking available to all who desire it. Every piece will feature an innovation as well as showcasing the watchmaking philosophy of Serge Michel and Claude Greisler, co-founders of the modern Armin Strom, both born in the same year, 1978. Thus the System 78 collection is born.”
Armin Strom Gravity Equal Force Ref. ST19-GEF.90.AL.M.35 Technical specifications
Hours, minutes, seconds, power reserve indicator
Armin Strom manufacture Caliber ASB19
Automatic winding with micro-rotor, Geneva-drive equal force barrel, offset display with subdial seconds
Regulating system: Balance wheel with 4 regulating screws
Power reserve: Geneva stop-work limited to 72 hours
Dimensions: 35.52 mm x 11.67 mm
Frequency: 3,5 Hz (25,200 vph)
Finishing: Hand-finishing to the highest quality level
Number of components: 202
Sapphire crystal and case back with anti-reflective treatment
Diameter: 41 mm
Height: 12,65 mm
Water resistance: 3ATM
Offset with subdial
Manufactured by Armin Strom – stainless steel with hand finishing
Delivered with a genuine black alligator leather strap and stainless steel ardillon buckle.
A stainless steel double-folding clasp is an option.
Gravity Equal Force Ref. ST19-GEF.90.AL.M.35 Price: CHF 16,900
Armin Strom today: Serge Michel and Claude Greisler in partnership
Children born in the same year growing up in a town like Burgdorf (population 15,000) are likely to know each other, either through school, family, or mutual friends. Such is the case with Serge Michel and Claude Greisler, who grew up in the town where Armin Strom, famous for his watch skeletonisation skills, had his watch shop and workshop. When the plastic Swatch watch was launched, having been developed and produced in the nearby city of Bienne, Serge was hooked and started collecting Swatches, following in the footsteps of his father, who is also a watch collector. It was a passion that would continue throughout his life. But while Serge went on to study marketing, Claude decided to become a watchmaker, first attending the watchmaking school in Solothurn before specializing in the restoration of vintage and complicated movements at the CIFOM technical school in Le Locle, concluding his studies there with a specialization in movement development.
Both Serge and Claude had known about watchmaker Armin Strom from a very young age. Serge not only remembers peering through the window of his store to look at the watches, but also the fact that Armin Strom was a local celebrity known for travelling far and wide to deliver his watches to customers. Claude had also known about Armin Strom from an early age, since his parents owned an optician’s shop right next to Armin Strom’s store in the historic centre of Burgdorf. In Serge’s case, Armin Strom became a family friend and at convivial dinners the talk would often turn to watches and watchmaking. It was hardly surprising, therefore, that the family friendship evolved into a business relationship in 2006 as Armin Strom was considering how to ensure the future of his name and reputation.
“I was convinced that this is a fantastic opportunity to maintain this tradition of skeletonizing watches and develop it for the future, and my family agreed,” says Serge. “That was back in 2006, but at the time we didn’t really have the knowledge about watchmaking. We had the passion, but we needed someone who was an expert on the watchmaking side of things, which is where Claude comes in. He joined me in 2007, and we started to set up the brand Armin Strom and change the direction from purely handmade skeletonised watches to a fully equipped manufacture, which we are today.”
For Claude Greisler, it was like a dream come true. “When Serge first called me and talked about taking the brand to the next level with a factory and taking the brand over from someone from the same town as us, it was the perfect mix. Armin Strom had always been interested in the mechanics of the movement, so to be able to take this philosophy forward was a fantastic opportunity.”
The core element in the vision of the duo was always to consider the movement as the very heart of the watch, which meant that the company would need to be a manufacture to produce its own movements. “This was not just a question of designing our own movements,” explains Claude, “but being able to take exactly the kind of brass that we wanted and the type of steel that we wanted to make the best possible plates, bridges, screws and pinions that we could and to do the electroplating and finishing, as well as the assembly, all in-house.”
Armin Strom: A fully integrated manufacture
While Armin Strom is a vertically integrated complete horological manufacture, no new watch movement would ever have seen the light of day were it not for Claude Greisler, who puts ideas such as the one for the revolutionary Mirrored Force Resonance movement down on paper before they are transferred to computer-aided design programmes to start modelling the movement. Like so many things at Armin Strom, all of this is done in-house, with the dimensions calculated down to a precision of one micron to provide the inputs for the machines that will eventually produce the smallest of components.
At Armin Strom, the majority of components in the movement, with the exception of the escapement and balance spring, are produced in-house. Small round components like screws, pinions and gear wheels are produced by profile-turning machines, which gradually whittle away long steel or brass rods from the side to cut teeth or axles. Larger components such as base plates and bridges are produced from brass on CNC machines, which are capable of machining along multiple axes consecutively using different tools for different operations, moving the component using robotic arms.
Particularly small and delicate components, such as smaller bridges, levers and springs, are produced using wire erosion. This involves threading a wire that is not much smaller than a human hair through a tiny hole in the metal. An electrical current running through the wire reacts with a solution in which the entire working plate is dipped, thus “eroding” minuscule amounts of the metal. This allows particularly delicate operations to be carried out while maintaining the structural integrity of the metal. In fact, Armin Strom does not produce any of its components by stamping because of the stresses that this places on the metal.
Once the raw components are manufactured, they are engraved, bevelled, polished and decorated with circular graining or Geneva stripes by hand before moving to the in-house electro-plating department. Here, all steel and brass components are first given a gold plating before a layer of nickel is added to prevent corrosion and harden the surface. After cleaning, the parts are then dipped in other electroplating baths to give them their final colour such as rhodium, ruthenium or rose gold. It is only thanks to its mastery of electroplating techniques inside its own workshops that Armin Strom can allow customers to choose preferred colours for the coating on different components.
Only then can the individual components of the movement be passed on to the watchmaker for assembly. After setting the jewels into the base plate and bridges, the watchmaker adds the gear train and mainspring. After the escapement and balance wheel are positioned, the movement finally comes to life…only to be completely disassembled, cleaned and dried before being re-assembled and lubricated. After several days of testing the precision, the watch is finally ready.