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Open Source Equatorial Mount

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#51 Pinbout

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Posted 14 August 2013 - 10:31 AM

put it in sketchup

http://www.javelin-t...sw-to-sketchup/

#52 jhayes_tucson

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Posted 14 August 2013 - 12:30 PM

After taking a quick look at your design, I'll give you a few things to think about: You can get better load capability (both radial and axial) and zero out backlash by using tapered roller bearings. They need a preload, which can be done with a threaded nut bearing on the inner race along the axis. Shaft stiffness becomes a little more important but you want to pay attention to that anyway so you should look at the effect of hollow shafts on bending moments and torsional rigidity. In any case, you are wise to incorporate some way to add and control friction for each axis. With any kind of roller bearing, the motion will be way too smooth to balance without friction control. I believe that you are better off putting a mounting boss on the RA axis for a small alignment scope. Mount it with alignment pins and a quick release so that it can be easily removed. Putting a hole through the Dec axis to accommodate an alignment system isn't that good for rigidity; though it helps with weight. Finally, where do you put drives on this design?

John

#53 m. allan noah

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Posted 18 August 2013 - 03:39 PM

All these renderings just show us the same info over and over again. We all know what the outside of a black GEM looks like :)

We need a cutaway view to help you develop the idea further.

allan

#54 Adam Brunette

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Posted 19 August 2013 - 09:57 PM

Hello Allan,

I generated this one a few days ago, but didnt get a chance to post it yet.
Posted Image

And a high rez iso sectional:
https://lh3.googleus...AANIo/RL8upk...

The yellow rectangle with the notch is the worm wheel and the gold block with circle touching the worm wheel is the worm gear and mounting block. The grey block next to the worm block is the worm /servo mount.

The needle roller bearings are not shown on either axis so use your imagination where the cutouts are on the axis bearing preload shaft. The shaft inside the axis shaft is the clutch shaft for tightening the clutch.

-Adam






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