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A. Lange & Sohne Zeitwerk

May 10, 2009


A Lange & Sohne recently introduced a new model, the Lange Zeitwerk. It features a jumping numerals mechanism that displays hours and minutes in a larger format - for excellent legibility. Inside is a manufacture calibre L043.1 that utilizes a constant-force escapement and a patented barrel.

Jumping Numerals


"The manufacture calibre L043.1 features a jumping numerals mechanism for hours and minutes. Designed according to the Lange principle, it consists of two minute discs and a large hour ring. Precisely once a minute, a constant-force escapement generates the necessary switching impulse. Viewed through the caseback, the movement presents a host of further forwarding-looking inventions."

Patented Barrel


"The patented mainspring barrel delivers a large amount of energy, especially when all three discs need to be simultaneously advanced at each full hour. As the mainspring relaxes, the barrel rotates in the minimized friction bearing. Conversely, the mainspring barrel bearing with the higher friction rating is involved while the watch is being wound. Thus, a slightly greater effort is required when winding the watch, but in return, more of the energy stored in the mainspring remains available for powering the movement. Additionally, the size of the mainspring can be reduced without any concessions in terms of energy yield."

Constant-Force Escapement


"A constant-force escapement is positioned between the barrel wheel and the balance. This patent-pending mechanism has two crucial functions. On the one hand, it generates the switching steps for the instantaneous jumps of the hour and minute displays, using the strike-train principle with warning followed by drop-and-release as often found in striking clocks. Never before has such a mechanism been integrated in a wristwatch. On the other hand, the constant-force escapement drives the balance with nearly uniform power during the entire autonomy period and thus enhances the rate stability of the movement."

First Impression

The Zeitwerk's level of complication is quite remarkable. It features a patented mainspring barrel that stores up to 36-hours of power reserve (displayed at 12 o'clock). A "constant-force" escapement converts the mainspring energy equally to power the analog seconds subdial (at 6 o'clock), as well as the mechanical-digital jumping hours (at 9 o'clock) and minutes (at 3 o'clock). The jumping numerals disc design is so precise, that the switching action actually allows an attentive listener to acoustically distiguish between a single minute advance (1416 times a day) and a collective progression at the full hour (24 times day). This allows you to hear the time, similar to a minute repeater.


Technical Specifications:

Lange manufacture calibre L043.1, manually wound, crafted to the most exacting Lange quality standards, decorated and assembled by hand; precision-adjusted in five positions; threequarter plate made of untreated German silver; balance cock engraved by hand; jumping minutes; constant-force escapement

Number of movement parts


Screwed gold chatons

Lever escapement

Oscillation system
Shock-resistant glucydur balance with eccentric poising weights; superior-quality balance spring manufactured in-house with patent-pending attachment system (balance spring clamp), frequency 18,000 semi-oscillations per hour, precision beat adjustment system with lateral setscrew and whiplash spring

Power reserve
36 hours when fully wound

Jumping hours and minutes, small seconds hand with stop seconds, power-reserve indicator

Operating elements
Crown for winding the watch and setting the time

Case dimensions
Diameter: 41.9 millimetres
Height: 12.6 millimetres

Movement dimensions
Diameter: 33.6 millimetres
Height: 9.3 millimetres

Solid silver

Ref. Nos.
140.021 Yellow gold case, champagne dial
140.029 White gold case, black dial
140.032 Pink gold case, argenté dial
140.025 Platinum case, rhodié dial

Time bridge
German silver, untreated (YG and PG case) or rhodiumed (WG and Pt case)

Glass and caseback
Sapphire crystal

Rhodiumed gold

Hand-stitched crocodile strap and Lange prong buckle in solid gold or platinum

A. Lange & Söhne

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