A. Lange & Söhne TOURBOGRAPH “Pour le Mérite”

A. Lange & Söhne’s third Lange tourbillon watch, the TOURBOGRAPH “Pour le Mérite” was launched on the occasion of the company’s twin anniversary on 7 December 2005. It was the second one endowed with a fusée-and-chain transmission and the first one with a fusée-and-chain transmission plus a rattrapante chronograph.

The world’s first one-minute tourbillon in a wristwatch format that features a fusée-and-chain transmission combined with chronograph and rattrapante functions is breathtaking.

Matching the A. Lange & Söhne TOURBILLON “Pour le Mérite” that was presented in 1994, this wristwatch again unites the two likely most complex mechanisms dedicated to enhancing long-term rate accuracy but it goes a step farther.

This exceptional watch integrates a timekeeping mechanism that even allows lap times to be measured. It is the second Lange watch with the attribute “Pour le Mérite”, an accolade for the superb horological skills of Lange’s master watchmakers.

The name alludes to the order of merit inspired by Alexander von Humboldt and sponsored by King Frederick William IV in 1842 for outstanding, predominantly scientific accomplishments. Indeed, the TOURBOGRAPH “Pour le Mérite” is the so far most complex and exclusive wristwatch ever made by A. Lange & Söhne.

A LANGE &SOHNE TOURBOGRAPH Pour le Mérite in Platinum, Ref. 702.025

So far, only one Lange watch of the new era had the prestigious attribute added to its name: It was the TOURBILLON “Pour le Mérite”, one of the first four Lange creations presented to the public in Dresden in October 1994.

It was the world’s very first wristwatch with a fusée-and-chain transmission. The ambitious project was launched in the early 1990s by Günter Blümlein, one of the watch industry’s most profound visionaries. He was also the co-founder of Lange Uhren GmbH and the company’s managing director for many years.

In view of the limited capacity of the then still very young Glashütte manufactory, Blümlein had secured the co-operation of horology specialists Renaud & Papi in Le Locle for development. Blümlein also sketched out the first ideas for the further evolution of the project with the TOURBOGRAPH in mind.

The intricate fusée-and-chain mechanism takes into account a circumstance subject to the laws of physics: The mainspring of a mechanical watch does not deliver the same torque when fully wound as when nearly unwound. The power in the final phase of unwinding weakens and can cause rate inaccuracies. For this reason, the mainspring barrel and the fusée in the A. Lange & Söhne TOURBOGRAPH “Pour le Mérite” are interconnected with a delicate chain. It alone consists of more than 600 parts.

While the watch is being wound via the crown, the chain is wound up on the tapered fusée and the spring in the barrel is tensioned. Then, the spring’s power is delivered to the movement via the fusée and thus with constant torque. When the mainspring is fully wound and exerts its full force, the chain pulls at the smaller circumference – or lever – of the fusée and when the mainspring’s power declines, it pulls at the larger circumference of the fusée.

This ingenious mechanism improves the rate accuracy of the watch across the entire power reserve range. But what good would it do if, in the crucial moment when the mainspring must be rewound, the movement were to stand still? This is why a planetary gear train composed of 38 parts – it has a diameter of only ten millimetres and is accommodated inside the fusée – was created. It keeps the movement running even while the mainspring is being wound.

The TOURBOGRAPH “Pour le Mérite” is the third Lange timepiece to feature one-minute tourbillon – a micromechanical marvel designed to protect the balance against the cumulative effects of gravity. The other models with this mechanism are the TOURBILLON “Pour le Mérite” and the LANGE 1 TOURBILLON, a wristwatch based on the legendary LANGE 1.

The one-minute tourbillon has a number of striking features, among others the decoratively curved, mirror-polished steel tourbillon cage which alone consists of 84 meticulously finished components. True to another Lange tradition, the staff of the filigreed cage is crowned on both sides with a diamond endstone. This is one of the remarkable details that dates back to Lange’s pioneering achievements of the distant past; it was a telling sign of “1A” quality.

The tourbillon contains the crucial escapement and rate-regulating elements such as the pallet lever, the balance, and the hairspring; this complex assembly rotates about its axis once a minute. Its purpose was originally to compensate for the influence of gravity on geometrical offsets of the balance. In other words, an error incurred in the first half of the tourbillon cage’s revolution was compensated in the second half.

In the past, Lange has repeatedly redefined the benchmark in the domain of horological complications, especially in the construction of exclusive chronographs. Two recent examples are the DATOGRAPH which was launched in 1999 and the LANGE DOUBLE SPLIT presented in 2004.

The exceptional TOURBOGRAPH borrows the second half of its name from this chronograph legacy. It features the very culmination of mechanical timing technology, the rattrapante function, modestly suggested by the third push piece at 10 o’clock.

The twin sweep seconds hands, delicate and superimposed, allow additive time measurements of up to 30 minutes as well as – concurrently – the measurement of any number of lap times. The TOURBOGRAPH “Pour le Mérite” features two classic column wheels in a very elaborate mechanical subsystem to dependably and precisely control the two chronograph functions.

The TOURBOGRAPH “Pour le Mérite” watch was proposed in a limited edition of 101 pieces: 51 in platinum and 50 in gold.

Technical details

Model: A. Lange & Söhne TOURBOGRAPH “Pour le Mérite”

Lange manufacture calibre L903.0, manually wound, crafted to the strictest Lange quality criteria, assembled and decorated largely by hand; precision-adjusted in five positions; plates and bridges made of untreated German silver; chronograph bridge engraved by hand; 30.0 millimetres in diameter; 8.9 millimetres high
Number of parts: 465 (w/o chain), of which tourbillon cage: 84
Number of chain parts: More than 600
Jewels: 43, of which 2 diamond endstones
Screwed gold chatons: 6
Balance: Shock-proofed glucydur-alloy screw balance,
Nivarox 1 hairspring with a frequency of 21,600 semi-oscillations per hour (3 Hertz).
Power reserve: 36 hours when fully wound

Hours, minutes, power reserve, one-minute tourbillon with fusée-and-chain transmission, chronograph with rattrapante function

Operating elements
Crown for winding the watch and setting the time, chrono push piece at 2 o‘clock, reset push piece at 4 o‘clock, rattrapante push piece at 10 o‘clock

Material: Platinum or 18K yellow gold
Diameter 41.2 millimetres
Height: 14.3 millimetres
Glass and caseback: Antireflection-coated sapphire-crystal glass(hardness 9)

Solid silver, argenté
Hands: Blued steel, chrono hands in gold-plated steel

Hand-stitched crocodile strap with Lange prong buckle in solid platinum

Limitation: 101 in total, of which 51 in platinum and 50 in gold

Courtesy: Lange Uhren GmbH

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