|
German Chamber Clock
Circa 1670
This clocks stands 18.5" in height, by 12" wide, by 10.5" deep. The clock was entirely
handmade by a Blacksmith or a person who could easily work with metal in Southern Germany.
If the clock were to run for 24 to 30 hours, it would have had to stand roughly 30 feet
high in a courtyard, as the weights fall an average of 7"/hour. The tips of the hands are
brass and reflect even the slightest light very early in the morning. The movement has a pig-tail
pendulum and a Crown Wheel escapement.
The correct length for the pendulum rod was calculated as follow:
The correct pendulum length was determined by calculating the number of beats per hour. My
calculations are based on:
- the First Wheel having 96 teeth, which engaged to a 16-tooth cog,
- this connected to a 48-tooth Second Wheel, which engaged a 6-tooth cog,
- this was connected to a 33-tooth Contrate Wheel, which engaged a 6-tooth cog.
Then all of this was finally connected to a 14-tooth Crown Wheel escapement.
The resultant calculation gives 7,392 beats per revolution of the First Wheel, which revolves
once per hour.
Therefore, the pendulum should be about 230 milimeters, or 9.1 inches long. Q.E.D.
I wrote to a Professor Dr. Richard Muhe at a Clock Museum in Germany (Deutsches Uhrenmuseum
Furtwangen-Schwarzwald) or German Clocks Museum. His response was as follows:
Your clock, an iron-wall clock, dates approximately from the late 17th century. It could have
been produced probably in Southern Germany, perhaps in the region of the city of Ulm, but also in
other regions of Europe. The clock has a verge escapement and a pendulum on the front side. It
seems, that some pieces, especially of the movement, may have been reconstructed or replaced.
Also, the hands, the numbers, the pendulum, which earlier could have been regulated by a balance
wheel, may have been replaced. The dial may be a little younger than the
clockwork, but that could also depend on variations in the painting. The small arabic numbers can be
original, because they were also usual in their time. Your calculations for the pendulum will be
correct. The driving weight should be chosen as low as possible. A price is very difficult to be
calculated, because of the different modifications during the life of the clock and because of the
uncertainty of the origin. But you may suppose more than 5000. - DM in Germany.
|
