Author Topic: A Gravity Escapement  (Read 13484 times)

Offline jrbeall

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A Gravity Escapement
« on: March 17, 2006, 02:48:00 PM »
I have been interested in the gravity escapement for some time and now I am about to finish a clock with that device.  Apparently this escapement was used mostly in tower clocks and tall case clocks.  I wanted to build a small shelf clock but this presented several problems.  The esape wheel usually has six teeth or arms.  I designed a double three arm wheel like the one shown in the book, "Clock and Watch Escapememnts" by W. J. Gazeley.  A three arm wheel will rotate once every six beats.  Of course this means that the  train needs another element if it is to run any length of time.  Since my clock is all wood I couldn't use very tiny wheels and pinions so I ended up with 50,  70, 80, 80 wheels and all 10 tooth pinions.  To further slow things down, I added a compound pendulum with a 4 second period.

     The beauty of the gravity escapement is that the pendulum beats independantly of the trains power.  Since I am still interested in using bows as power, which vary wildely in their strength between fully wound and nearly relaxed,  the gravity escapement seemd like a good bet.

     I had no measurements or information other than the picture in the book so I just drew it up, hoping it would work.  It does work very well although I havn't yet finished the compound pendulum.  The little constant torque spring motor I used to test the clock is too weak to run it but I can see that it wants to run and that is encouraging.

     I will post pictures as soon as I get the pendulum finished and figure out how I will poser it.

Offline jss

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fyi --gravity escapement in motion
« Reply #1 on: March 30, 2006, 09:25:14 AM »
The National Watch and Clock Museum
Learning Center Gallery
"The Beeler Escapements"
Six-Legged Gravity Escapement
1979---
http://www.nawcc.org/museum/nwcm/galleries/beeler/89_47_20.htm

Offline jrbeall

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A Gravity Escapement
« Reply #2 on: April 16, 2006, 10:54:35 AM »
Here are some pictures of my new clock with a gravity escapement.

JR