SIHH 2014: A. Lange 1815 Tourbillon with Stop Seconds and Zero-Reset
by Kyle Stults on January 20, 2014
Pinit

A. Lange 1815 Tourbillon Pink Gold

Presenting the A. Lange & Soehne 1815 Tourbillon with stop-seconds mechanism and zero-reset.  Available in platinum (limited edition 100 pieces, Ref 730.025) or pink gold case (non-limited, Ref 730.032).  For the very first time, an A. Lange & Söhne timepiece unites the stop-seconds mechanism for the tourbillon with the zero-reset function (more on how this works, below).  The interaction between the two patented mechanisms makes it possible to stop and set the new 1815 Tourbillon with one-second accuracy.  This is useful, of course, it is impossible to exactly set most watches equipped with a tourbillon because the tourbillon can not be stopped.

A. Lange 1815  Tourbillon with Stop Seconds and Zero-Reset

Limited edition 100 pieces platinum / non-limited in pink gold

39.5mm x 11.1mm platinum or pink gold case, on alligator strap with platinum or pink gold buckle

A. Lange 1815 Tourbillon Platinum Closeup

The combination of Arabic numerals with the classic railway-track minute scale is reminiscent of historic A. Lange & Söhne
pocket watches.

A. Lange 1815 Tourbillon Pink Gold Dial Closeup

In comparison with earlier versions, the diameter of this tourbillon was increased by nearly one millimetre to 13.2 millimetres.  You can see the arbor of the tourbillon carries the subsidiary second hand; in the interest of visibility it is crafted from blued steel:

A. Lange 1815 Tourbillon Pink Gold Tourbillon Closeup

 Lange manufacture calibre L102.1

manually wound, 72 hrs power reserve, crafted to the most exacting Lange quality standards, decorated and assembled by hand; precision-adjusted in five positions; plates and bridges made of untreated German silver; seconds bridge engraved by hand

A Lange Caliber L102.1

 

A Lange Caliber L102.1 Closeup

The hairspring and balance wheel are crafted in-house – Lange is one of the few with such production capability.

Stopping the Tourbillon

In 2008, Lange’s calibre designers put an end to this usse. At the time, they succeeded in braking the balance inside the rotating tourbillon cage directly and without delay. When the crown is pulled, a complex lever mechanism is activated which presses a movable V-shaped spring onto the balance  wheel and stops the balance instantaneously. The new 1815 Tourbillon is also endowed with this patented mechanism, which can partly be observed through the aperture in the dial. But this time, Lange’s product developers went a step further. They paired the stop mechanism with the also patented zero-reset mechanism. It causes the blued-steel hand of the subsidiary seconds dial to instantly jump to the zero position when the crown is pulled, thus facilitating the synchronisation of the watch by positioning the minutes hand exactly above a minutes stroke and starting the watch with one-second accuracy.

Druck

The interaction between two patented mechanisms enables the watch to be set with great accuracy. When the crown is pulled, the balance inside the tourbillon cage stops instantaneously and the seconds hand jumps to the zero position. The watch can now conveniently be synchronised with a reference watch or a time signal.