GearHeads Corner

Hi Art,
I want to use the ticker escapement to make a clock so instead of a neat kenetic  sculpture, I would like to use a flywheel and have it work like classic geneva wristwatch escapement.
1. I'm thinking that I'll need to make a "hairspring" - which won't be a problem - I can do that.
2. I should probably limit the rotation to about 270? an have the "flywheel" hit stops at that point.
3. I would like it to "tick" every 1/2 second but that may not be possible, it may have to be faster.

So where I would like to hear your opinion is on how heavy should the flywheel be in order to trigger the escape mechanism and what diameter of flywheel would you suggest as a starting point.

I know this will be a big trial and error exercise but perhaps your thoughts could cut down on wood wastage (failures).

John

Hi John:

  Funny really, Im just planning a similar project. I also intend to use a spring with a larger flywheel,
about 16" round. Im planning ( at this point anyway) to design it as a plant stand that rotates the plant
once every few hours so that a different part of the plant faces the sun each day. ( In truth Ill probably
be lucky to get a day from a wind...but we'll see.. trial and error as you said..)

 I wouldnt limit it with stops,sounds like wasted energy , greatest success in terms of time running will
be to have it run as a natural system, so let entropy based on the hairspring and rotational inertia guide its
rotation. If you wish 270 degrees ( Good number IMO), let the strength of the spring make it run to 270..
adding radius screws and mass to tune it to that speed and to help balance it. ) In my view, the slower the
better, the longer the device will work. Ideally, Id like a large wheel that takes 5 - 10 seconds to make a
period..but the math may be impossible .. I havent crunched anything yet..

   The period will be a function of the mass and the radius of the wheel and the spring. Look at a chrono and youll
see small  screws that can be set out or turned in, this changes the radius of the wheel and thus the rotational inertia and the
time of cycle and the balance. (Coupled with the spring used and the friction of the bearings and the wind resistance of the wheel...
alot of factors.
  So far Ive only drawn a rough diagram for myself, but Im planning a floor standing frame with a 16" or so wheel
on a chrono with a sprung clock spring as my hairspring.. Maybe 30" tall or so in total. I figure most wives who
wont hang a wall ticker would probably allow a standing plant stand that slowly ticks and rotates the plant.
, so its a viable project and allows for some artistic creativity.

     I only began the thought process a week ago, but heres a rough sketch of my thoughts on a
"Gearotic Plantstand for the Wife". First sketch, just a thought really..

 

Art

(Added snapshot showing gears on chrono escapement)