GearHeads Corner

Hi Art
I would like to build an actual clock using the Chrono Escapement.  I'm sure I can do this however since there is a balance wheel instead of a pendulum - is there any way to predict the oscillations of a balance wheel.

My present thinking is to simply build a 6 inch balance wheel and mess with the rim weight and a "hair" springt until I get something reasonable.  I would like to get a one second or half second oscillation but I don't know if that can be done.  Once I have some idea of the oscillations I'll be able to design the rest of the gear train. 

Any ideas?

John

John:

Interesting question. Turns out your cycle time is equal to

2 * PI * SquareRoot( WheelsInertia / k )

k is the springs strength..  The Inertia is in Kilogram/meters . I imagine it woudl be quite difficult to
calculate it directly without a lot of complexity.. Inertia changes with shape.. So Id run an experiment
and scale it. If you keep the springs between two models the same ( thus a constant k ), then you can
compare two systems and consider the weight of the balance wheel to be a linear ratio of the smaller
model.  Or so Id think.. ( and I could be way off on that assumption..

Art


Art

Hi Art,
Thanks for the information.
I can certainly calculate or closely approximate the inertia of the wheel but I have no idea of what spring I'll end up with - might even be home made so I think I'll save the paper and pencil and use intuition and see where it leads me.

Thanks again

John

Exactly what Id do.. :)

Art