A. Lange Sohne - LANGE 31

Innovative Features

In 2007 A. Lange & Sohne introduced a novel timepiece - LANGE 31 -featuring a few horological breakthroughs. The manual-wind timepiece offers a power reserve of a whole month, having suggested the watch's name. LANGE 31 features one more innovation - a constant-force escapement. The escapement is responsible for uniform power delivering during all the period of 31 days. Lange has also redeveloped the venerable key winding mechanism.

The power of 31 days means the owner of the LANGE 31 will have to wind the watch for just 12 times a year. The continuous rate stability provided by the escapement during the whole month implies the proper accuracy of timekeeping.

Two stacked mainspring barrels have been applied by A. Lange & Sohne watchmakers for storing the necessary amount of energy. Their inside diameter is 25 mm. The twin barrels need 3/4 of space of the movement's footprint. The length of every barrel is 1,850 mm. As a result, the two mainsprings are 5-10 times longer than those applied in other wristwatch movements.

If to unite the energy of the mainsprings, it will be enough to lift a Swiss chocolate bar of 100 grams over 10 feet. The brand's watchmakers witnessed one more problem - the components of a common winding crown train are too delicate for winding such strong mainsprings. The decision was suggested by the 'key technology' of the brand's historic pocket watches. A square socket key was interposed through a special aperture in the sapphire-crystal case back. It transmits the energy to the spring barrels. The key was provided with a built-in backstop ratchet. This way it becomes possible to wind the timepiece smoothly as with a regular crown. At the same time, a torque limiter keeps the springs from occasional over-tightening.

Adolph Lange's Heritage

The brand's founder, Ferdinand Adolph Lange, was working upon the constant-force issue. In 1866, the watchmaker invented a 'one-second remontoir' that represented a constant-force escapement with jumping seconds. The invention was used for Lange's precision pocket watches. Later, Lange developed a similar appliance to be used for for the large house clock featured at the brand's headquarters. At present day, the clock with an impressive 10-meter long pendulum, tells Lange workers and Glashutte citizens the precise time.

More than 140 years later Lange's watchmaking descendants used the founder's discoveries to develop the new caliber L034.1 movement offering the biggest power reserve - 31 days. LANGE 31 is aimed for daily use. Having comprised useful innovations, it provides convenient timekeeping, displaying the accurate time longer than any other hand-wound watch.

LANGE 31's Peculiarities

LANGE 31 is housed in a platinum case measuring 46 mm in diameter and 15.9 mm in hight. The circular 31-day power-reserve indicator is located in the right-hand half of the solid-silver dial. The last segment of the indicator in red, reminding the timepiece's owner when it is time for watch-rewinding.

The large Lange date window is placed on the left side of the dial - it adds the necessary harmonious balance to the face. The watch displays the time in hours, minutes, and small seconds, with stop seconds. The sapphire-crystal back showcases the inner workings of the timepiece. The movement's plates and bridges are produced from untreated German silver. The movement comprises 406 thoroughly hand-finished individual parts. Its balance cock is hand-engraved. There are four screwed gold chatons.

LANGE 31 goes with a hand-stitched crocodile leather strap featuring Lange prong buckle in solid platinum.