LANGE 31 Power pack in white gold and classic grey For nearly a decade, the LANGE 31 has been the first and only mechanical wristwatch with a power reserve of 31 days and a patented constant-force escapement that continuously delivers uniform torque. Located between the mainspring barrel and the going train, this ingenious mechanism assures the ultimate in precision. At SIHH 2017 in Geneva, A. Lange & Söhne is presenting a new design variation in white gold with a grey dial. It is limited to 100 watches. LANGE 31 in white gold with a grey dial At first sight, the sleek grey dial of the LANGE 31 in the 45.9-millimetre white-gold case does not reveal any sign of the power hidden inside its manually wound calibre. Only the white 31 at the upper end of the large power-reserve indicator and the small inscription beneath the Lange outsize date modestly refer to the fact that when fully wound, the movement will run for an entire month. It is a formidable technical challenge to endow a mechanical watch with a power reserve of 744 hours – and so is assuring superb rate accuracy from the first to the last day. This is because the twin mainspring barrel with its two 185- centimetre-long springs delivers an enormous amount of torque at the beginning when Glashütte, January 2017
fully wound, which then gradually declines toward the end of the power-reserve period. Thus, a separate technical device is needed to guarantee constant force delivery in the interest of maximised rate accuracy. The device is referred to as the constant-force escapement. In the LANGE 31, this device between the twin mainspring barrel and the going train delivers a constant amount of energy to the escapement every ten seconds, so consequently, the balance always oscillates with the same ideal amplitude. The result is superior precision from the first to the thirty-first day when a limiter mechanism stops the movement. The function of the constant-force escapement is readily observable. A look through the sapphire-crystal caseback reveals the triangular cam attached to the fourth-wheel arbor. It controls the mechanism with an ingeniously designed pivoting lever to recharge the remontoir spring with fresh energy every ten seconds. The powerful mainsprings are tensioned with a separate key that inserts in a square socket in a recess of the sapphire- crystal back. Its technical features include an integrated backstop ratchet for smooth and easy winding as well as a torque limiter that prevents unintentional overwinding of the springs. The artisanal finissage of the horological power pack lives up to all of the expectations that connoisseurs around the world associate with the A. Lange & Söhne brand.
About A. Lange & Söhne Dresden watchmaker Ferdinand Adolph Lange laid the cornerstone of Saxony’s precision watchmaking industry when he established his manufactory in 1845. His precious pocket watches remain highly coveted among collectors all over the world. The company was expropriated after World War II, and the name A. Lange & Söhne nearly vanished. In 1990, Ferdinand Adolph Lange’s great-grandson Walter Lange had the courage to relaunch the brand. Today, Lange crafts only a few thousand wristwatches in gold or platinum per year. They are endowed exclusively with proprietary movements that are lavishly decorated and assembled by hand. With 59 manufacture calibres developed since 1994, A. Lange & Söhne has secured a top-tier position among the world’s finest watch brands. Brand icons such as the LANGE 1 with the first outsize date in a regularly produced wristwatch and the ZEITWERK with its precisely jumping numerals display, rank among the company’s greatest successes. Sophisticated complications such as the LANGE 1 TOURBILLON PERPETUAL CALEDAR, the ZEITWERK MINUTE REPEATER or the TOURBOGRAPH PERPETUAL “Pour le Mérite” reflect the manufactory’s determination to achieve ever-new pinnacles in horological artistry.