The RICHARD LANGE JUMPING SECONDS is characterised by an intelligent combination of two mechanisms that functionally complement each other: A one-second constant-force escapement ensures ultimate precision. The jumping mechanism guarantees crisp legibility of the time; it advances the large seconds hand by exactly 60 steps per minute. Thanks to the ZERO-RESET mechanism, equipped with a multi-disc clutch, the watch can be synchronised quickly and comfortably: When the crown is pulled, the seconds hand jumps to the zero position. The RICHARD LANGE JUMPING SECONDS is the latest model in a series introduced by A. Lange & Söhne in 2006, which has repeatedly leveraged innovative solutions to add new facets to the scientific observation watch.

The jumping seconds mechanism ranks among the classic complications in precision horology. Pocket watches featuring this technology were once used to determine sidereal or solar time as well as geographical longitude. But even in short-time measurements today, for instance when taking a pulse, it is convenient to be able to read the time in full seconds. The jumping seconds mechanism has played a pivotal role in A. Lange & Söhne's history. After all, Ferdinand Adolph Lange developed a "one-second movement with a jumping hand" as early as 1867. Ten years later, the newly founded Imperial Patent Office granted one of its very first patents for his invention to the manufactory.

A big stage for the jumping seconds

The rhodié-coloured regulator dial with its large seconds circle at the top draws the observer's attention to the smallest of the three units of time. The smaller hour and minute circles arranged beneath it are shifted to the left and right. The sleek platinum case with a diameter of 39.9 millimetres underscores the functional aesthetics of the dial architecture.

Ten-hour countdown on red

Ten hours before the power reserve is depleted, a red indicator – inside a triangular aperture in the dial where the hour and minute circles intersect – reminds the owner to rewind the watch.

Constant force from start to finish

The new L094.1 manufacture calibre masters all challenges that are associated with the development of a jumping seconds mechanism. Technically, it stands out with an ingenious arrangement that distributes constant-force generation and the seconds jump to two wheel trains, but also allows them to interact. The first wheel train extends from the mainspring barrel to the balance and, in one-second intervals, uniformly delivers energy to the escapement via a constant-force device. Visible through an aperture in the train bridge, the mechanism has a double function: It compensates not only the gradually waning force of the mainspring, but also offsets possible torque fluctuations while the seconds jump is executed. The result is a constant amplitude across the entire power-reserve range of up to 42 hours. Superior rate accuracy is guaranteed as well thanks to the balance wheel with eccentric poising weights and the free-sprung balance spring crafted in-house.

The secret behind the seconds jump

The mainspring barrel powers the jumping mechanism via the second wheel train. Its task is to convert the balance frequency of six semi-oscillations per second into one single step of the seconds hand. As was already the case with Ferdinand Adolph Lange's invention, this process is controlled by a five-point star attached to the escape-wheel arbor. It can be observed beneath a transparent sapphire-crystal disc as it rotates about its own axis, together with the escape wheel, once every five seconds. Every second, one point of the star liberates the so-called flirt. This long lever, powered by the mainspring, then executes an instantaneous rotation through 360 degrees, after which it is arrested by the next point of the star. The 360-degree rotation, transmitted by the wheel train connected to the fourth-wheel arbor, moves the seconds hand to the next full-second marker. At the same time, the jump switching impetus is used to deliver fresh energy to the remontoir spring of the constant-force escapement.

Reliably back to zero

The RICHARD LANGE JUMPING SECONDS is endowed with a ZERO-RESET mechanism. The clutch on the fourth-wheel arbor consists of three discs and a special hand-shaped spring. The clutch disc in the middle is secured to the fourth-wheel arbor; in the closed state, the spring firmly presses the top and bottom clutch discs together. The clutch thereby immobilises the large seconds hand between the abrupt acceleration and deceleration cycles that occur every second in the normal operating mode. Pulling the crown activates a complex system of levers that block the balance with a stop spring and open the clutch. This separates the fourth-wheel arbor from the wheel train and allows virtually frictionless zeroing. For this purpose, the ZERO-RESET lever is pivoted against the heart cam, thus instantly returning the seconds hand to the 12 o'clock position. Pushing the crown home closes the clutch and releases the balance again: The movement can restart.

Limited-edition masterpiece

The finissage of the 390-part, manually wound movement complies with the strictest Lange standards. The bridges made of untreated German silver and decorated with Glashütte ribbing, the hand-engraved balance cock, eight screwed gold chatons, as well as lavishly decorated and polished surfaces are some of the artisanal highlights that, in their sophistication, match the technical perfection of the limited 100-piece edition of the RICHARD LANGE JUMPING SECONDS in platinum.