Central Impulse Chronometer: the Story Continues

As Bernhard Lederer marks his 63rd birthday this year, he continues to show that he's earned his place among the foremost contemporary watchmakers.

Bernhard Lederer introduced the Central Impulse Chronometer as a full-fledged watch this summer as a complete version of the prototype nominated in the Chronometry category at last year's GPHG (the prize was taken by Ferdinand Berthoud's Chronomètre FB 2RE.2).

The watch builds on the idea first put forward by Breguet who invention of échappement naturel (natural escapement) which was later developed by George Daniels in his double-wheel chronometer escapement. The devil's in the detail.

Lederer altered the construction using the double-wheel escapement by Daniels as a starting point. He changed the triangular central lever stone, replaced the steel escapement wheels with titanium ones, and increased the angle between the receiving pallets from 100 to 120 degrees, bringing them closer to the escapement wheels.

This means the wheels firmly but gently push the pallets over a longer course of joint traveling, which results in improved impulse transmission. The double-wheel escapement in Caliber 9012 was also given a remontoir d’egalité constant force mechanism, recharged in ten-second intervals.

The impressive movement powering the Central Impulse Chronometer is enclosed in a case measuring 44 mm in diameter and 12.2 mm in height. Its highlight is that the watch has two domed sapphire crystals.

This may be nothing new on the dial side, but a second crystal placed over the movement on the caseback certainly does look unusual. It's there for a good reason. The case has a rounded side and is essentially a glass vessel which offers lateral views of the movement.

A number of different versions of the Central Impulse Chronometer were initially presented, including one with a completely closed dial. The new version has a checkerboard of guilloché squares in the center (Lederer's proprietary pattern).

Two aperture openings form a stylized figure eight, where each circle has its own small seconds hand controlled by an independent remontoir. The Central Impulse Chronometer model was released in two 25-piece limited editions, one with a blue dial and the other with a rhodium-plated dial.