Thursday, February 26, 2015

Frictional winding

Due to the fact that the clock seems to need about 10 lb of weight, it seems like the endless chain mechanism I had intended to use probably won't work.  In particular, it basically requires doubling the drive weight, which doesn't seem like a good idea.  So instead, I've opted to try a simpler mechanism for winding.  Merely winding a few turns of cord around the drive pulley seems to give quite a bit of friction -- enough to hold the drive weight with a small amount of force on the other end. 


Specifically, it looks like if the drive weight is the 9 lb 8 oz from before, a 7.5 oz counterweight seems to hold it in place.  In this case, since there are two weights that need to be held clear of the pendulum and each other, I've used a pair of pulleys to run the cord.


This seems to work well enough, when the drive weight runs down, you can lift the drive weight and gently take up the slack with the counterweight.

No comments:

Post a Comment