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Posted by Si Ballenger on March 10, 2006, 7:24 pm
wrote:
>Hello,
>A project I'm working on entails a medical skeleton's forearm, laying
>flat on a table, which needs to rotate left and right in order to point
>to various items on the table. Currently, I have a hole drilled in the
>tabletop, with an extra-strength servo mounted underneath. The servo
>gear sticks up through the hole, where it is screwed to the 'elbow' of
>the skeletal arm, and can motivate the arm as needed.
>So far so good, but the servo has to overcome an awful lot of friction
>when pointing the arm at something. Would anyone be able to recommend
>some kind of turntable or other setup, which could support the arm up
>off the table, just high enough to eliminate most of the friction,
>while allowing a servo gear to still attach at the 'elbow' and do its
>job? I'm guessing that an extension of some kind might also be needed
>to make the connection from the servo up through the middle of the
>turntable to the arm....
>Thanks in advance,
>--Alex
WalMart has a plastic lazy susan gizmo for ~$2.50 that lays flat
and is ~10" across (roller bearings are around the outside edge).
For projects needing to rotate heavier objsects I've looked at
spacing it up off the surface around its edges such that a servo
could be underneath and rotate it 180 deg with out the servo
having to support the weight above it.
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> A project I'm working on entails a medical skeleton's forearm, laying
> flat on a table, which needs to rotate left and right in order to point
> to various items on the table. Currently, I have a hole drilled in the
> tabletop, with an extra-strength servo mounted underneath. The servo
> gear sticks up through the hole, where it is screwed to the 'elbow' of
> the skeletal arm, and can motivate the arm as needed.
> So far so good, but the servo has to overcome an awful lot of friction
> when pointing the arm at something. Would anyone be able to recommend
> some kind of turntable or other setup, which could support the arm up
> off the table, just high enough to eliminate most of the friction,
> while allowing a servo gear to still attach at the 'elbow' and do its
> job? I'm guessing that an extension of some kind might also be needed
> to make the connection from the servo up through the middle of the
> turntable to the arm....
> Thanks in advance,
> --Alex
>