Riefler pendulum

Precision pendulum clock from Clemens Riefler , which has a Riefler pendulum; with a rate deviation of ± 15 ms / day it is one of the most precise mechanical watches ever built.

The Riefler pendulum is a temperature-compensated pendulum for pendulum clocks , which was developed around 1880 by the physicist and precision watchmaker Sigmund Riefler .

He had a design patented that achieved temperature compensation more easily than the grate pendulum that was common up to that time .

description

The Riefler pendulum simplified the temperature compensation to achieve the accuracy of pendulum clocks to less than a tenth of a second deviation per day.

This was made possible by a pendulum rod made of the newly emerging Invar steel, which had such low thermal expansion that the compensation could be achieved with a much shorter length. Since the Invar steel could not yet be manufactured so precisely that a reproducible thermal expansion could be achieved, Riefler suggested using at least two compensating sleeves one behind the other and combining them from different materials depending on the required compensation. By keeping the total length the same, the compensation could be adjusted over a wide range without changing the pendulum length.

Further measures to improve the accuracy were the spring escapement (Sigmund Riefler 1889) and the gravity escapement by Clemes Riefler (1913). The watch cases were partially evacuated and vibration dampened.

Around 1900, when the astronomers and time services were aiming for an accuracy of 0.01 seconds per day, most of the moving parts and the dial (with adjustable pointer friction) were relocated to a synchronized slave clock and the master clock was completely evacuated, which in 1920 already resulted in an accuracy of only a few milliseconds of deviation per day. See Shortt clock .

literature

• Sigmund Riefler: The nickel steel compensation pendulum. Verlag Wolf, Munich 1902.
• Sigmund Riefler: Precision pendulum clocks and nickel steel compensation pendulums. Ackermann publishing house, Munich 1907.
• Karl Ramsayer : Geodetic Astronomy. Handbook of Surveying Volume IIa, § 33 (Pendulum Clocks). JBMetzler, Stuttgart 1970.

Web links

• Rediscovery and repair of the Riefler precision pendulum clock No. 711. Radiophil.com, accessed December 10, 2013 . 

Individual evidence

1. ↑ Sigmund Riefler: DRP No. 100870 Pendulum with nickel steel rod and several interacting compensation tubes. (PDF) Year 1897. German Patent and Trademark Office, accessed on December 10, 2013 .