A. LANGE & SÖHNE
The Lange 31
No other watch runs longer: The new manually wound A. Lange & Söhne timepiece has a power reserve of one month. That is why it has been named the Lange 31. Another innovation, a constant-force escapement, assures that power delivery is uniform throughout the entire 31-day period. Additionally, Lange reintroduces the venerable key winding mechanism.
The construction of a mechanical wristwatch with a power reserve of a whole calendar month, not to mention constant rate accuracy across the entire period, was one of the few as yet unmastered horological feats. Now, it is reality: the Lange 31. With it, the horological year is now subdivided into 12 “winding sessions”. To store this amount of energy, the Lange 31 features two stacked mainspring barrels with an inside diameter of 25 millimetres. The prominent twin barrels occupy three quarters of the movement’s footprint. Each measuring 1,850 millimetres in length, their combined energy is enough to lift a 100-gram bar of Swiss chocolate 320 centimetres – more than 10 feet. The leverage delivered by a key makes it possible to choose a transmission ratio that would be inconceivable with a crown. A square key, inserted through an aperture in the sapphire-crystal caseback, delivers the energy to the spring barrels. The key features a built-in backstop ratchet to allow smooth winding as with a regular crown, and a torque limiter prevents accidental over tightening of the springs.
It stands to reason that a movement with such an extraordinary power reserve cannot constantly run at a stable rate without special technical precautions. So Lange’s engineers sought – and found – a different solution: the constant-force escapement. It is based on an auxiliary spring that is periodically rewound by the mainspring and always builds up the same torque, regardless of the state of wind of the mainspring. As it relaxes, this pretensioned so-called remontoir spring on the fourth-wheel arbour always delivers the same amount of energy to the escape wheel. Every ten seconds, this spring, attached to a stud, is retensioned by 60 degrees at its outer end.
The motion sequence of the constant-force escapement can be observed through the sapphire-crystal caseback. A transparent sapphire jewel reveals the fascinating interaction of the three-point cam with the pivoting lever. On the bottom line, the constant-force escapement prevents the waning torque provided by the mainspring barrel from diminishing the rate accuracy of the watch. The result: uniform energy delivery, constant amplitude, same rate accuracy from the first to the thirty-first day on which a shutoff mechanism halts the movement.
The platinum case of the Lange 31 has an impressive diameter of 46 millimetres and an overall height of 15.9 millimetres. After all, it takes space to store so much time. And the circular 31-day power-reserve indicator that occupies nearly the entire right-hand half of the solid-silver dial requires space as well. It is the hallmark of a true breakthrough in horology. The last segment, in red, reminds the owner that after a full month has elapsed, it is finally time to rewind the watch. The Lange outsize date on the left side harmoniously balances the face. Needless to say, the Lange 31 also showcases all of the quality features that make timepieces by A. Lange & Söhne so coveted around the world. A glance through the sapphire-crystal back reveals the screw balance, the whiplash precision index adjuster on the hand-engraved balance cock, screwed gold chatons, and lavishly decorated elements in the classic Lange style.
Jules Audemars Jumping Hour Minute Repeater
The hours sing out once more on the new Jules Audemars watch from Audemars Piguet. They also dance across the dial with its jumping display and elegant blued Arabic numerals. Combining two in-house specialities – the Minute Repeater and Jumping Hours – this marvel of precision and harmony perpetuates Audemars Piguet’s supreme expertise in the field of complicated watches. With its case and dial featuring a new take on classical styling, it gives a fresh boost to the Jules Audemars collection. This delightful new model will be music to the ears of connoisseurs the world over.
The Audemars Piguet Calibre 2907 driving the new Jules Audemars Jumping Hour Minute Repeater is clearly inspired by the movement of the historical 1992 model, whereas the architecture has been entirely redesigned to match the new case dimensions. Audemars Piguet has implemented innovative solutions to accommodate the relatively large movement and the complex striking mechanism within a diameter of just 43 mm. Blending traditional expertise and cutting-edge technologies, the Manufacture has also endowed the audible mechanism with all the fine-tuned technical details. In particular, the movement has been equipped with a device that does eliminate any audible gap when the watch does not need to strike a quarter (e.g. 9:13); the sequence of 9 hours and 13 minutes is thus struck smoothly and without any interruption.
In terms of aesthetics, Audemars Piguet has redesigned the round case of the Jules Audemars collection in a resolutely contemporary spirit. The slimmer bezel ensures maximum dial opening, creating a fine impression of space and lightness. The shimmering reflections of the finely polished and brushed pink gold or platinum surfaces emphasise the pure lines of the case featuring two lugs smoothly integrated with the bracelet. The dial also reinterprets the signature Jules Audemars classicism in a beautifully balanced composition. Its opaline base is adorned with a minute track and applied blued Arabic numerals radiating a modern and dynamic appeal. The hour aperture with its disc jumping instantly from one figure to another every sixty minutes is distinguished by a bevelled opening. The minutes are displayed in the dial centre by a flame-blued steel hand in the “Poire Paris” style. The small seconds tick away on a snailed subdial at 6 o’clock with a hollowed structure highlighted by a track motif and an original hollow-tipped baton hand.
A sapphire crystal caseback enables one to admire the hand-wound Calibre 2907 with its 412 parts and its balance beating at 21,600 vibrations per hour. All parts are finely bevelled and rhodium-plated and, depending on the specific part, decorated with “côtes de Genève” or stippled. In an exquisitely refined styling detail, the “côtes de Genève” adorning the bridges are lined up with the three gear-train jewels. This beautiful mechanical symphony is surrounded by the two Minute Repeater gongs that are struck by the two small hammers.