Torsion pendulum clock

The name derives from the Drehpendeluhr is a torsion pendulum that rotates like a balance in a horizontal plane. Typical representatives of this type of watches are the so-called " Anniversary Clocks " that reach a duration of several months to over a year with an elevator. They came to the beginning of the 20th century in large numbers and were particularly common in the United States, England and Germany.

As the inventor of Drehpendeluhr applies Johann Anton Harder (1811-1888), who on September 16, 1877 received a patent for a torsion pendulum along with the watchmaker Lorenz Jehlin. After failed attempts, the watch company A. Willmann & Co. and Gustav Becker, both based in Freiburg in Silesia, the end of August 1881 treasure was awarded the contract to manufacture watches years, resulting in later years developed the watch factory in Triberg. After expiry of the patent rights then took some leading German watch manufacturer this type of watch on the program.

The movements are round or square pillar works with Graham or pin inhibition. Early copies had partly also a verge escapement. It is driven by a tension spring in the barrel. The pendulum mass initially consisted of a solid brass plate, and later Bimetallreife with adjustable weights and mercury compensation pendulum were used to compensate. Younger specimens have 4 steel balls as the pendulum weights.

The pendulum is suspended from a fine steel wire which is twisted around its axis and acts as a torsion spring. The vibrations of the torsion pendulum is isochronous. For a complete cycle of oscillation are approximately between 15 and 30 seconds, which is a comparatively long time is needed. Due to the slow rotation speed of little energy is lost by the air resistance of the torsion pendulum, so long run times can be achieved even with a small energy storage. Disadvantages of the design is its sensitivity to shocks and generally only moderate accuracy. This adds up in conjunction with the long transition period to a higher gear deviations.

With modern replicas models are commonly used, although externally the same rotational pendulum clocks, but in which the pendulum rotates independently from the movement and has no influence on the transition of the clock.

Replica with balance and rotating ornamental pendulum