GearHeads Corner

Hi y'all,

So this the first use I've made of the Gearotic designs. Its the first iteration of a drive design for a sculpture I'm working on.

http://www.youtube.com/watch?v=c4Cp8wWFn58

Mechanism goes like this: Geneva wheel (with positive lock groove on the driver) to 1:2 gear chain to Scotch yoke.

Still need to work on the housing and coupling the yoke to an angle doubling mechanism.

Gotta say Gearonics takes soooooo much of the pain out of gear chain design thankyou very much!!

Nice mchanism. What triggers its reverse motion?

Glad to see GM used for such things. Im working on allowing more
kinetic art type of mechanisms as well.

Thx
Art

There's a wheel attached to the back of the smaller gear (made it transparent in the video so you could see the gears) which has a pin which is in turn inside the slot of the Scoth yoke. As the pin wheel does a half rotation it pushes the yoke one way & on the second half rotation pushes the yoke the other way. The move & dwell cycles of the gears are curtesy of the Geneva wheel

If that makes sense :D

:)

Yes, that makes sense. Amazing how our language just isnt compatible
to explain such things..

Art

LOL yeah thats what I was thinking when I typed that out.

Nice Job Nic...


Cheers
Bob ;)

Thanks.

When I get the full mechanism designed I'll post a walk through. There will be 4 of the above modules couped via bevel gears to a prime mover.

Honestly cant express how much easier you guys have made this, thanks again for the great software.

OK so here are two of the drive modules in their housing...

http://www.youtube.com/watch?v=CpclBWJ5KME

Its a shame about the bevel gear export in Gearotic :(

Will have to find another way to couple my prime mover the drive modules.

Nic:

  Very nice.

  Is the problem on the bevels output just a bad stl? Ive done some work on it recently to close holes and such,
but we'll see how the next version works for you. Im in the process of adding a special type of geneva gear, so
you should have that to play with at about the same time on next release.

Thx
Art

Thx,

Yeah the STL is too rough to use also the 3D DXFs (which would be great) are incomplete only giving some of the surfaces and no complete volume. I was wondering if it would be possible to output the stack of contours tha DXF appears to be using without any surface inerpolation and then doing the volume rendering myself in SW?

Cant wait to see what you've done for the Geneva wheels.

Nic:

  Ill see if I can do it instead with a stack of contours. It wont be immediately as its a tough job. As you can imagine, the bevels use a lot of triangulation,
and they arent really built using contours..which I probably should have done, but instead use an algorithm that makes them in triangle form without a contour step. Ive added most of the code I need to triangulate contours directly, then use quads as the contour joining method.
  Ill likely focus on that as soon as I finish this geneva code. The Geneva's I opted for are a single level rather than a normal dual level geneva, so they can be cut in 2.5 D with no problem or pocketing, and these ones can have a staggered time sequence in them. I call them Rythmic Geneva's as the user will be able to set a rythmic sequence to the rotation of the pinion. They should be out within a week if Im lucky ( or industrious. ) :)

Art

Yeah I appreciate that 3D geometry can be a nightmare when you have to force it into a particular file format. Have you considered IGES or Parasolid?

Oh its not the file format, its the geometry itself. Just abit of a bitch making a parametric bevel in a closed form, triangulation of tigth contours
without losing res can be troublesome unless I do something liek a delauney on it, which tends to take too long to process. At any rate,
revisiting the solids is something I do intend to redo at some point..

Art

Ahhh I see, may be worth taking the computational hit for a more robust algorithm. Anyway good luck that quite a challenge.

More geary goodness! Have now added bevel gear train to the mechanisms, simplified version in video below...

http://www.youtube.com/watch?v=v4F5MtpvXq0