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Responsive and precise The flyback function and the precisely jumping minute counter

Der 1815 CHRONOGRAPH BOUTIQUE-EDITION mit Flyback-Funktion

In 1999, A. Lange & Söhne introduced the DATOGRAPH, its first manufacture chronograph of the modern era. It was endowed with two additional useful complications that today are still integrated in many Lange chronograph models: the flyback function and the precisely jumping minute counter.

Sketch of flyback mechanism

A function invented in the early days of aviation

The so-called flyback function allows an ongoing time measurement to be interrupted and a new one to be started instantaneously by merely pressing a button. It combines three steps – stop, reset to zero, and restart – into one. In chronographs without the flyback function, these three steps must be executed consecutively.

The concept behind this complex function dates back to the era when flight-deck crews still navigated with maps and watches and often had to react very quickly to suddenly occurring events. With the triumph of electronic measuring instruments, this classic function, mainly used by pilots, sank into oblivion. In Lange chronographs, the flyback mechanism is experiencing a renaissance – with a newly developed design.

Sketch of the precisely jumping minute counter

Precision even at the top of the minute

Many chronographs have a minute counter that advances minute by minute rather than continuously. The switching process sometimes takes one or two seconds. If such a watch with a delayed-action minute counter is stopped in the vicinity of a full minute, it is often unclear whether the counter hand has already incremented forward or not.

The precisely jumping minute counter, however, advances by one graduation exactly after 60 seconds have elapsed, even if the time measurement is stopped at that very moment. This useful mechanism was already incorporated in historic pocket watches and high-end wristwatches crafted during the last century. But Lange’s calibre engineers refined it in an ingenious way: a patented switching lever now allows the watchmaker to precisely determine the timing of the minute counter jump without having to disassemble the movement.

The mechanism of the precisely jumping minute counter

Display: Accurate to the mark. The precisely jumping minute-counter. Under a transparent representation of the DATOGRAPH UP/DOWN the precisely jumping minute-counter mechanism is shown and correctly positioned. After removal of the watch outlines, the operation of the mechanism is shown several times from different perspectives. The minute-counter lever sweeps the rotating stepped snail. After a lapse of a minute, the lever’s feeler-tooth is tripped by the step. The pawl at the other end of the minute-counter lever pulls the minute-counter wheel, and with it the minute-counter, round by one division. At the end, the individual parts of the mechanism are named.

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