1815 “Homage To Walter Lange” - Technical Review

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1815 “Homage To Walter Lange” - Technical Review - A. Lange & Söhne
A.Lange & Söhne have produced a very special line of timepieces, with just one steel example set to be auctioned off for charity on 13 May, in Geneva.

“The Homage To Walter Lange” is powered by an entirely new movement equipped with a central “jumping seconds” hand and regular subsidiary seconds at 6 o’clock.

1815 “Homage To Walter Lange” – Revue technique

 

“Flirt and Star”

The jumping seconds complication is mounted above the train / barrel bridge as opposed to being built into the movement and is controlled by a “flirt and star” mechanism. The escape wheel has a five-pointed star shaped wheel (star) fixed to the top of its central axis which both make a complete revolution once every 5 seconds. There is a tensioned lever (flirt) which makes contact with the star wheel at one end and has a pinion attached at the other.

1815 “Homage To Walter Lange” – Revue technique

 

Once every second the lever in contact with the star wheel makes its way to the very tip of the tooth, the spring is released and completes one full revolution causing the attached pinion to also turn. That pinion then engages with an intermediate wheel which turns the wheel the jumping seconds hand is attached to. The centre seconds hand then makes a complete one second jump with this process being completed every second, when the “flirt” comes into contact with the tip of the “star”.

Powering the jump

The jumping seconds complication must of course receive power the same as the rest of the movement does. A normal gear train is powered by a mainspring and to effectively operate the jumping seconds without a separate mainspring some of that power needed to be borrowed. This is achieved via a wheel (ratchet wheel) that is mounted concentrically on a train wheel already receiving power from the mainspring, that power is then transferred to the jumping seconds hand via a series of independent wheels.

1815 “Homage To Walter Lange” – Revue technique

Start/stop function

The movement is fitted with a start/stop mechanism for the jumping hour complication which when operated does not affect the running of the watch. When the pusher to control the complication is pressed, a lever, activated by a column wheel, blocks the “flirt” or pushes it out of the way of the star wheel, ensuring the star wheel doesn’t trip the lever and cause the jumping seconds hand to advance.

This technical feature could potentially cause problems, forcing the whole watch to come to a halt. Imagine putting a metal pole into a series of gears, the whole mechanism would stop not just the one section, so to avoid this happening two clicks or slipping gears are used. When the jumping seconds is stopped, the ratchet wheel mounted on the train wheel will continue to run as it is powered by the base movement, the clicks will then “slip” on the teeth of the ratchet wheel allowing the power to escape, ensuring the jumping seconds stays stopped and the movement continues to function.

A fitting tribute to a great man.

1815 “Homage To Walter Lange” - Technical Review

 

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