Pendulum lens
The lens- shaped pendulum body is referred to as the pendulum lens (also lens of the pendulum ) in pendulum clocks in several styles .
description
Common style clocks of this type in the 19th century are the Viennese Laterndluhr (around 1900) and their cheaper replicas with wooden pendulums, the old German pendulum clocks and, in the 18th century, the French cantilever clocks.
The flat lens shape is on the one hand a decorative element due to its metallic sheen, on the other hand it is advantageous for the accuracy of the watch. Because the air resistance of the swinging pendulum is relatively low, which is why changes in air pressure have little influence. For precision pendulum clocks of this type, the pendulum rod could be equipped with temperature compensation using suitable metal rods and the case could be partially evacuated.
There is a regulating nut under the pendulum lens to regulate the clock rate . The oscillation amplitude can be determined on an angle scale and brought into symmetry by changing the inclination of the watch case, which also improves the rate.
literature
- Viktor Pröstler: Callwey's handbook of clock types , Callwey-Verlag, Munich 1994
Web links
- Pendulum lens. UhrenLexikon, accessed December 11, 2013 .
Individual evidence
- ↑ Fritz von Osterhausen: Callweys lexicon. Munich 1999, ISBN 3-7667-1353-1 , p. 241
- ↑ Rudi Koch (Ed.): BI-Lexicon - clocks and time measurement. VEB Leipzig, 1986, ISBN 3-323-00100-1 , p. 132