Re: [CAD_CAM_EDM_DRO] Re: RotoBot hexapod

I've had bad luck with my posts not showing up, so I will make this one
brief and see if it goes.

Some ideas that come to mind for the traction ring:
1. Roll a gear rack into an arc or circle. Could be either an internal
or external gear, or even a face gear if the rack is not very wide. I
used to work at a company that did just that for an internal gear
segment. Probably most versatile
2. Wrap a bicycle chain around the drum, with a slot to hold it in
place to create an external chain "gear". The motors would then have
sprockets attached to them. Probably cheapest and easiest to implement
for a quick and dirty prototype.
3. Mount a milling head to a lathe crosslide (just did this with my
Sherline column onto my 14x40 lathe) and cut the external gear directly
onto the drum. Probably most precise, but size limited to lathe swing
and tooling clearance.

Regards,
Raymond Gage

Graham Stabler wrote:

>>Does anyone have any ideas on how to implement this approach, in a
>>home built machine? I mean, I could probably go to a machine shop
>>and have parts made, but that's just throwing money at it...I'm
>>thinking in terms of the way we build other small routers, truly >
>>hacking a solution. And, would any existing programs be able to
>>control it?
>>
>>
>
>I do think that this and the hexaglide/triaglide solutions are more
>realistic for the amateur. I have to say that although the
>rotational method looks elegant I can't think of a way of doing it on
>a real budget. You really want a rack around the circumference and a
>motor with pinion on each of the rotating arms. Fairly normal
>bearings in the middle and some sort of roller system to stop each of
>the arms from flexing upwards or downwards.
>
>The hard part would seem to be the ring shaped rack. Perhaps a
>timing belt could be glued into the inside of a ring. That is
>perhaps a little too much of a botch. Either that or you need a huge
>planetary gearbox to take to pieces.
>
>If it counts for anything, I'm up for it.
>
>If the machine is there, the software will follow.
>
>Graham
>
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