Jaeger-LeCoultre Atmos Clock Retailed by Türler

By Charlie Dunne

Introduced in 1928, the Atmos clock is not only Jaeger-LeCoultre’s longest continually produced timepieces, but it remains one of the most iconic clocks within horology. With such a unique history and breadth of models, it is perhaps the quintessential clock for watch collectors to add into their home/office. Like the later photoelectric (solar powered) clocks of Patek Philippe, the Atmos is also a timepiece that demands little upkeep, but can be purchased at a fraction of the cost.

Jean-Léon Reutter: Inventor of The Atmos Clock

The Atmos clock was invented by Jean-Léon Reutter, a Swiss engineer living in France. Reutter was quite a gifted individual by his mid 20s, having developed the initial iterations of the Atmos clock for several years before its official introduction in 1928. As early as 1926, Ruetter was filing several patents which lay the foundation for the clock to become a success.

Patent GB280536A

Patent GB331764A. “Means for re-winding clocks and like mechanism by the effect of variations in the temperature of the air”. (Applied Sept. 19, 1929. Approved July 10, 1930). Image credit: Espacenet.

GB356216A (Applied 1929-06-04. Approved 1931-09-04)

It appears Reutter would eventually license the clock through the prestigious manufacturer LeCoultre as early as circa 1935. This can be inferred by advertisements from retailers such as Türler highlighting the association with the Atmos (just one year after the merger between Jaeger and LeCoultre):

“1935: LeCoultre takes over the manufacture of the first "ATMOS" driven by "perpetual temperature fluctuations". The name LeCoultre is once again closely linked to progress in the watchmaking industry”.

“Was the perpetual clock invented?

They write to us: The latest issue of the "Journal suisse d'Horlogerie" brought us a surprise. The young engineer Jean-Leon Reutter, son of M . Max Reutter, finance director of the city of Neuchàtel, built, after patient research (they lasted more than ten years), a perpetual clock. The inventor imagined using variations in atmospheric pressure and temperature as a propelling force. This idea is not new, but what is good is that the watch movement will use this force a thousand times weaker than that of an ordinary spring movement. These pressure and temperature variations are detected by a fluted metallic box similar to that of aneroid barometers. This tiny force is stored in a coil spring which, after having served as a flywheel-regulator, applies this force to a very slowly oscillating torsion pendulum, suspended by an invar wire. A variation of one degree in temperature alone is enough to keep the clock running for 24 hours. A change in barometric pressure of 3 mm. of mercury produces an identical effect. The horioge made by M . Reutter has been working in a precise way since 9/11. According to forecasts, this clock, made up solely of unalterable materials, will be able to work for thousands of years, i.e. until the mechanism wears out.”

-Le Nouvelliste (January 26, 1928)

How It Works

Every machine requires energy for its operation, be it mechanical, electrical or heat. Our smallest machine, the clock, has been mainly powered by mechanical energy since the earliest times, and only recently by electrical energy. In the case of stationary clocks, it is primarily a weight that falls under the influence of gravity or the tension of an extended spring that performs the work required for operation. Recently, attempts have been made to use thermal energy to convert it into work. That's what happened with the AtmosVhr invented by engineer J.R. Reutter. This watch, manufactured by the prestigious Swiss watch factory Le Coultre in Le Sentier under the Atmos Jaeger-LeCoultre brand and distributed by the company A. Türler & Co. in Zurich and Berne, deserves thanks to its unique construction and the perfect mechanical execution a more detailed appreciation. ; The inventor of the Atmos clock uses two principles in its construction, one of which, the so-called torsion balance in physics known under the name of Coulomb's torsion balance, is ancient, as the first wheel clocks were already equipped with it several centuries before the invention of the pendulum clock . The second is the use of temperature fluctuations in the surrounding air to generate the necessary energy. Instead of the pendulum generally used as the regulating organ in table and wall clocks, the Atmos clock has a balance wheel of unusual dimensions suspended on a thin wire, which performs very slow rotary movements. A back and forth swing takes exactly one minute with a mathematical pendulum would require a length of 894.6 meters! and a point of the circumference describes 2XI/ revolutions, s 0 so that half the swing width, the amplitude, is 315-. Just as gravity causes the pendulum to oscillate in stationary clocks and the hairspring in transportable clocks, it is the torsional elasticity of the wire that keeps the balance wheel in constant rotation. But while pocket watches and chronometers oscillate 5 or 4 times per second, the Atmos clock has deviated considerably from previous practice The torque exerted by the wound spring is transmitted in the usual way to the wheel system, the minute and hour hands. Also noteworthy is the escapement required for every watch, which, as is well known, serves to ensure that the clockwork runs exactly in the rhythm prescribed for timekeeping. For the first time, the free anchor escapement was used in connection with the torsion pendulum, which otherwise only the most precise timepieces, the chronometers, have. Every 30 seconds, the anchor fork gives the otherwise completely freely oscillating torsion pendulum an extremely weak impulse so that the balance wheel always precisely maintains its prescribed swing width. As a result, the minute hand jumps every half minute.

The power requirement of the watch is exceptionally low, as the following comparison shows. The daily work required for operation (force X distance) is 78,000 cmg Astron with a Black Forest clock. Pendulum clock 10,000 cmg Pocket watch 1500—3000 cmg Atmos clock 30 cmg This extremely low power requirement of the Atmos clock is only due to the almost complete absence of pivot friction. The torsion pendulum with the 240 g balance has no track bearing at all, but only a locking device for transport purposes. The oiling of the watch has been completely dispensed with in order to avoid the resinification of the oil altogether, which is always associated with a considerable increase in the work of friction. The type of compensation for temperature fluctuations is also interesting. It is achieved using extremely fine wire of rectangular section (0.18X0.05 mm) made from “Elinvar”, a 28/nickel nickel steel alloy which, as the name suggests, has a fixed modulus of elasticity or torsion. (The “Invar” used for the pendulums of astronomical clocks with an invariable coefficient of expansion is an alloy of 64.3/steel and 35.7/nickel.) The coefficient of expansion is not equal to 0, but it is negligibly small. Since the massive balance wheel itself has no compensation, rate changes due to changes in the moment of inertia or the barometer reading are corrected in two ways. Rough adjustment is done by attaching small weights of /4 to 1 g to the balance, whereby the daily rate can be changed by 3 minutes per 1 g, fine adjustment by lengthening or shortening the suspension wire using a control knob. One rotation of the same causes a change in rate of 10 s, and that is to say that a shortening of the wire causes a movement and vice versa. In this way, the daily rate can easily be regulated to the nearest second. Finally, “some information should follow that will be of particular interest to technicians. The clock spring of 7X0.1 mm section has the respectable length of 1.7 m; it sits in a barrel with an internal diameter of 38 mm. Winded it makes 36 turns, relaxed 15 and lying freely on the table 6, so that 21 are available for the operation of the movement. The formula for the torque M is: M Eb d- 27xn 12 L this results in a torque of the wound spring of M 1500 mmg E modulus of elasticity (for clock spring 23.10 g/mm?) b width of the spring 7mm d thickness, :0.1 L— length, 1700.. n number of windings 30 The balance has a weight of G' it makes a simple oscillation in 30 seconds, as follows from the following formula for the oscillation time T: 22T oes V Mi directional moment, i. H. the torque exerted by the twisted wire when the balancer is rotated 1800 —— 857.30 E3 from the rest position. IJ— moment of inertia of the balance wheel (mr?) 40.885 g sec? mm? m mass of the balance - 0.02446 g g acceleration of gravity r— average radius Mi is to be calculated using the following formula: G dbM— 36 1 this results in: ; ; Mi * 0.44836 mmg G torsine modulus d thickness of the wire 0.05 mm b width ,„ 1 — length ,„ 110 mm As can be seen from formula 2), the swing width does not appear in it, in other words: the oscillations are isochronous, i.e. H. independent of the size of the deflection, which is a significant advantage compared to the pendulum, where this only applies to small deflections of a few degrees. The Atmos watch, a pinnacle of Swiss watchmaking, is interesting not only for technicians and physicists, thanks to the multiple problems it poses, but is sure to find the applause of a wider audience that appreciates its fully automatic and ultra-elegant execution will particularly appreciate.

-A. Steinbrüchel (Zürich)Neue Zürcher Zeitung (December 20, 1944).

Notable Atmos Owners

According to Jaeger-LeCoultre’s website “the Atmos was given to Presidents and other heads of state as an official gift. Fittingly it became known as the "President's Clock," a true showcase and symbol of Swiss precision and know-how. Whenever a President, Pope or famous actor visited Switzerland, they would receive an Atmos clock. England's Queen Elizabeth and Winston Churchill, France's Charles de Gaulle, American presidents John F. Kennedy and Ronald Reagan and Pope John Paul II, all received an Atmos clock adding to the piece's unrivalled legacy.”

Catalog

How It Works:

Certificate of Guarantee

The ephemera that accompanies timepieces are really a treasure to collect. Whether the catalogs or the buckles, these are very exciting to see. However, in my experience most items that are sold with JLC timepieces are incorrect and have been assembled to enhance the price. Most often it is American-market LeCoultre boxes, incorrect instruction/guarantee booklets with a wristwatch that is unrelated or from a different period. While I enjoy hunting for boxes, catalogs, and the likes, I will oftentimes be more cautious when I am evaluating a vintage timepiece that comes “full set” or with extra items. While the clock did need a service, the one year Certificate of Guarantee provided by Türler was out of date by over six decades.

Extract from the Archives

Upon receiving an email from Giuseppe Sciascia of Jaeger-LeCoultre’s Heritage Department, I was thrilled to see that the date on the Certificate of Guarantee would align with Extract from the Archives citing a production date of 1955. JLC would also mention this Atmos clock is designated as Model (or reference) “Classic V”. I personally have had a great appreciation for the Atmos over the years, and what I love about these Extracts is that they can often provide a small anecdote about a clock or watch that even the most passionate enthusiasts might not be able to know off the top of their head. The Extracts, just like the original ephemera, are very exciting elements for collecting Jaeger-LeCoultre and the service of sharing their information with collectors certainly elevates the brand.

Calibre 526

According to Atmos Atelier, the Classic V is powered exclusively by the calibre 526. The model/calibre was in production over the course of 1955-1984, lending insights that the Türler Atmos is an early example. The cal. 526 would also be used in the Atmos VIII (respectfully alongside the cal. 528, and cal. 528/1 ff).

Advertisements

Türler would be one of the strongest partnerships for Jaeger-LeCoultre. Throughout the years, many advertisements can be seen by the retailer highlighting JLC’s latest offerings (oftentimes including the Atmos). While many will focus on the more obvious Cartier, the close relationship with Türler should warrant more acclaim from collectors when it comes to Jaeger-LeCoultre timepieces with retailer or double-signed dials.

“Atmos, the clock that lives on air, is wound by minutest temperature changes.

Runs indefinitely.”

The dial features applied-Arabic numerals at 3, 6, 9 and 12, in addition to dauphine markers. This is the most consistent dial layout and also very common dial furniture from JLC during this period. One can notice the same approach in models like the reference 2975 and Memovox reference E 851.