A French Art Deco ambrolite Reutter patent atmos clock, circa 1935

Description

Reutter Patent Atmos

In 1927, Jean-Léon Reutter created his first prototype clock, with a driving spring that is wound by changes in temperature. After a number of adaptations and improvements, the design was patented in 1928. A commercial production line for the Reutter Patent Atmos was started in the middle of 1929. Several inventions made this technical marvel possible. He used a torsion pendulum, known from 400-day clocks, and by enlarging it, ensured a very low ticking count. He made the suspension wire from elinvar, an alloy insusceptible to temperature changes, which greatly improved precision. The movement was finely made and executed with ruby end stones, causing it to need very little energy. In fact, the clock only needs 1/1000th of the energy that a conventional movement requires. These improvements were combined with his winding mechanism, which consists of a drum that can turn between two blocking pins. Inside the drum there is a U-shaped glass tube filled with mercury and ammonia gas, of which one part is insulated. By changes in temperature, the ammonia gas expands or contracts compared to the gas in the insulated half of the tube. This causes the mercury to shift, and this motion turns the drum. This turning winds a spring which drives the mechanism. Between 1930 and 1938, these clocks were produced under the direction of Jean-Léon Reutter. In 1935, Jaeger-LeCoultre took over the patent and started plans to modify the winding mechanism. The production of the modified Jaeger-LeCoultre version commenced after the Second World War, in 1947. Because of these developments, the number of Reutter Patent clocks remained limited. The Reutter clocks were executed with different cases. Many of the Art Deco versions are fairly rare because they were too modern for the large public. Nowadays, these clocks are desired because of their fascinating technique and their iconic, timeless designs.

Atmos

The square 11-cm painted dial has Roman numerals and is signed ATMOS pendule perpetuelle and below VI BREVETS J.L. REUTTER made in France.

Pendule Perpetuelle

The movement is driven by a spring. This spring is wound by a mechanism which functions on changes in temperature and barometric pressure. It causes a drum to turn. This turning motion winds the spring. The exceptional movement requires very little energy to run. With only one degree Centigrade temperature difference, the clock can run for 48 hours. The clock is regulated by a large horizontal balance wheel with adjusting screws which has a thirty second oscillation time. Since there are always changes of temperature during the course of the day, the clock is wound continually and will run continually. That is why Reutter called ‘Pendule perpetuelle’ (perpetual clock).

Art Deco

The rectangular case is made of ambrolite a late 19th Century amber imitation plastic and has nickel plated brass mounts. The straight lines and canted base are typical for the designs of the Art Deco period, the unadorned but balanced style of the 1920’s and 1930’s.