A. Lange & Söhne, Glashütte i/SA, "LANGE 31 MONATS-WERK", Movement No. 69827, Case No. 179847, Ref. 130.025F, Cal. L034.1, 46 mm, 284 g, circa 2009
An extremely rare, large and heavy platinum Glashuette wristwatch in mint condition, with oversized date and 744 hours power reserve indicator - with original box, Lange booklet, operating instructions and guarantee
Case: platinum, sapphire glass screwed on back, "Lange" platinum deployant clasp. Dial: solid silver, rhodium-plated.
The LANGE 31 is the world’s first mechanical wristwatch with a power reserve of 31 days and a patented constant-force escapement. To deliver a power reserve of this magnitude, the movement must be able to store a large amount of energy. This task is handled by two mainsprings that are both 1850 millimetres long – about ten times as long as in mechanical wristwatches with a conventional power reserve.
Mainsprings of this length imposed considerable challenges on the engineers. The first obstacle was to transmit their tremendous energy to the movement in a gentle and uniform manner. For this purpose, they developed a patented constant-force escapement. The second challenge presents itself when winding the watch, a very time-consuming and cumbersome task, given the length of the springs. This is why the LANGE 31 is wound with a key. It generates much more leverage than a winding mechanism based on a crown.
机蕊 新款, 走動正常
机蕊 新款, 走動正常