pic: 114 2 speed Coaxial Crab Drive

[Greg Perkins]

Love this idea, I have some sick and twisted designs in my head that look like this. One question I have for you, ever think of making the four wheels orient in a square rather than a rectangle? That way you'd have a zero degree turning radius, and would be able to turn faster with more precision. That gearbox idea was similar to what I have thunked up, the only difference is you've got yours to cad allready. But I DO LOVE THE DESIGN!

[=Martin=Taylor=]

How are you going to tension the chain off of the globe. Are you planing on using one or two chains. I'd like to see a picture.

Keep up the good work.

Keep posting.

For the tensioning of the steering chain (the one that will be attached to the globe) I have a set idea: Two 1/4" plates, with two delrin rollers, running the chain to the steering sprocket. The two rollers will form a triangle with the globe sprocket, making a nice tensioning system, and giving the sprocket nice wrap.


Will post picture upon CAD completion of that system

[=Martin=Taylor=]

This is exactly what I have implemented into my own swerve design. I have had some bad experiences with Delrin chain tensioners, so I am wary of this approach. I may decide to use idler sprockets instead.

Have you considered timing belts? What are the pros/cons of using them.


(yeah, I'm too lazy to make a real chain in inventor (black-thing = chain))

I've used timing belts before... And had bad experiences with them. When doing a rapid change in direction, The belt tends to skip... aka bad stuff, bad noise, bad wear.

So chain seems like the better option... for this application, that is.

[lukevanoort]

I can't recommend idler sprockets enough, they're easy to work with, reduce your efficiency losses, and aren't too heavy. Here is a picture of our implementation of them on a u-bolt, this design can easily be mounted on some aluminum angle and can be used sideways (although the chain might be a bit more likely to fall off, but some sort of spacer on the u-bolt could solve that problem, if it occurs) a simple nut can adjust tension, or they can even be spring loaded, as I suggested here .