Rotary pendulum clock
The name given to the rotary pendulum clock is a torsion pendulum that rotates in a horizontal plane similar to a balance wheel. Typical representatives of this type of clock are the so-called "annual clocks", which have a running time of several months to over a year with an elevator.
history
Rotary pendulum clocks appeared in large numbers at the beginning of the 20th century and were particularly widespread in the United States , England and Germany. Its inventor is Johann Anton Harder (1811–1888), who, together with the watchmaker Lorenz Jehlin, received a patent for a torsion pendulum on September 16, 1877. After failed attempts by the watch companies A. Willmann & Co. and Gustav Eduard Becker , both based in Freiburg, Silesia , at the end of 1881 August Schatz was commissioned to manufacture annual clocks, which later became the annual clock factory in Triberg in the Black Forest . After the patent rights expired, some leading German watch manufacturers added this type of watch to their range.
mechanics
The clockworks are round or square pillar movements with Graham or pin escapement . Some early specimens also had a verge. It is driven by a tension spring in the barrel . The pendulum mass initially consisted of a solid brass disc, later bimetal rings with movable weights and mercury compensation pendulums were also used for compensation . Younger specimens have four steel balls as pendulum weights.
The pendulum weight is suspended from a fine steel wire that is twisted around its axis and acts as a torsion spring . The oscillations of the torsion pendulum are isochronous . A complete cycle of an oscillation takes between 15 and 30 seconds, i.e. a comparatively long time. Due to the slow speed of rotation, only little energy is lost through the air resistance of the rotary pendulum, so long running times can be achieved even with a small energy store. Disadvantages of the construction are their sensitivity to vibrations and the generally only moderate accuracy. In connection with the long running time, this can add up to larger rate deviations .
Replicas
In modern replicas, models are widespread that look like rotating pendulum clocks, but in which the pendulum turns independently of the mostly battery-operated clockwork and thus has no influence on the accuracy of the clock.
mechanical rotary pendulum clock
electric rotary pendulum clock
Rotating pendulum clock without winding or battery
literature
- Hans-Heinrich Schmid : Lexicon of the German watch industry 1850–1980. Company addresses, production program, company logos, brand names, company stories. Ed .: German Society for Chronometrie eV; ISBN 978-3-941539-92-1
Web links
Individual evidence
- ↑ DRP No. 2437
- ↑ Old clocks. Callwey Verlag, Munich. Issue 1, 1982. pp. 30ff.
- ↑ UH Activities Restoration Restoration of a chronometer. In: uhrenhanse.de. Retrieved August 7, 2012 .
- ↑ a b c Eric Smith: Repairing Old Watches . Callwey, Munich 1983, ISBN 3-7667-0673-X .
- ↑ Fritz von Osterhausen: Callweys lexicon . Callwey, Munich 1999, ISBN 3-7667-1353-1 .