Product Description

A. Lange & Sohne – Tourbograph Pour le Merite
REF# 712.050

Limited & Numbered Edition Of 50 Pieces Worldwide!
Homage To F. A. Lange Tourbograph “Pour Le Mérit”.

1. The case material used is 18kt “HONEY” colored gold, exclusively developed for Lange & Sohne. The honey gold has a subtle warm hue to it & has a color somewhere between white gold & yellow gold. With a Vickers hardness of over 300, this gold is about twice as hard as other gold alloys, making it more scratch resistant.
2. “Fusee-and-chain transmission”: In the Lange & Sohne fusee-and-chain mechanism, the flow of power between the mainspring barrel and the going train is established indirectly by a 636-part chain. One end of the chain is attached to the barrel drum and the other to the fusee. As the mainspring barrel unwinds, the chain wraps around it and reels off the fusee. When the mainspring is fully wound and thus exerts great force, the chain pulls at the smaller radius of the fusee where the leverage is smaller. As the springs tension diminishes, the chain pulls at the larger radius with the higher leverage. Thus, regardless of the state of wind of the mainspring, the same amount of torque is delivered to the escapement, resulting in improved rate accuracy. In the fusee-and-chain transmission mechanism, there is one situation when the cone rotates backwards: as the mainspring is being wound. To prevent the watch from stopping while it is being wound, Lange’s master watchmakers integrated a marvel of miniaturization inside the fusee. It is a tiny planetary gear train that assures uninterrupted delivery of power to the movement. Additionally, it is endowed with a pretensioning mechanism that allows the characteristics of the mainspring and of the fusee to be perfectly harmonized. Finally, the elaborate construction includes a device that blocks the winding mechanism just before the mainspring is fully wound and stops the movement just before it is fully unwound. Overall, the fusee-and-chain transmission comprises more than 700 parts.
3. 60 Seconds Tourbillon: The Tourbillon was developed to offset the disruptive effects of gravity on the balance wheel. It consists of a cage containing the balance, the pallet lever and the escape wheel. The balance & escapement rotate around their common axis going through all positions once a minute to average out the errors & thus resulting in a more accurate & consistent timekeeping. The construction of the Tourbillon mechanism in the Tourbograph is a true work of art, it consists of 84 parts yet weighs a mere 0.5 grams.
4. There are only very few companies in the world that possess the technology and the know-how to produce balance springs, The Lange & Sohne factory in Glashutte is one of them. The production of top-quality balance springs is one of the most complex processes known in horology. It imposes extremely strict requirements on precision, both in the mechanical shaping operations and in the thermal treatment phases. One example: springs must be rolled to an accuracy of 100 nanometers. This corresponds roughly to one-hundredth of the diameter of a human hair.

Features

• Solid 18kt “HONEY” gold case. Bezel, lugs & corners all finished with a polished finish. Case edges, button tips & case back finished with a fine satin/brushed finish.
• Solid silver dial with a fine sunburst guilloche texture in the center of the dial.
• Painted black Arabic Numeral hour markers, minute track & Chronograph indicators.
• Blued hands.
• Rattrapante(Split Second) Chronograph:
  • Large central blued seconds counter with a silvered “split seconds” directly beneath.
  • Silvered outer flange with black painted 5 seconds, one seconds & 1/3rd of a second indicators.
  • 30 minute counter sub-dial located at the 9 o’clock position.
• Power Reserve sub-dial indicator located at the 3 o’clock position,
• Tourbillon cage located at the 6 o’clock position.
• Lange & Sohne Caliber L930.0, beats at 21,600 vph, composed out of 465 parts (not including Fusee-and-chain) of which 84 are for the Tourbillon cage, contains 41 ruby jewels & 2 diamond endstones jewels – total of 43 jewels & has an approximate power reserve of 36 hours. This watch has a total of over 1000 components!
• All components (even those buried deep inside the movement which are hidden from the eye) have been meticulously finished and have polished beveled edges. The chronograph bridge is hand engraved making each watch unique.

Watch is pre-owned in as new and unworn condition. Watch is very newly pre-owned and comes 100% complete with all presentation boxes, booklets and warranty information.

Please feel free to contact our sales office with any questions.