Re: [CAD_CAM_EDM_DRO] Re: A "simple" Hexapod project - Joints

Graham,
I would go for a ball joint.
If you place compression springs between the plate and the base, you can
adjust
stiffness of it.
Alex

----- Original Message -----
From: Graham Stabler <eexgs@...>
To: <CAD_CAM_EDM_DRO@yahoogroups.com>
Sent: Tuesday, June 17, 2003 3:06 PM
Subject: [CAD_CAM_EDM_DRO] Re: A "simple" Hexapod project - Joints


> Although I am undecided as to whether or not to build a 3 axis or 5
> axis machine I have decided on a vertical slide type set up. This
> means no actuators as such to design, just bog standard rails and
> leadscrews. See files section "hexapod ideas" if you don't know the
> configuration.
>
> This means the mechanics consist of a stiff frame, 6 (for a full
> hexapod) or 3 (for a triaglide) linear slides, 3 or 6 leadscrews, 6
> fixed struts a table/router mount. And 12 joints.
>
> Carl has used gimbles and these have the advantage that they are
> simple to make and decent bearings can mean they have little slop. I
> am just wondering what other possibilities there might be, looking at
> large machines doesn't seem to help much as the joints are often
> covered or are mysterious ball joints that don't seem to be holding
> enough ball.
>
> I have just seem some ball joints on the web where the ball is held
> by a magnet, the largest was abotu 25mm in diameter and would hold
> 25kg.
>
> What about universal joints if also allowed to rotate?
>
> Another thing I have noticed is that sometimes joints are combined.
> Struts that join at the moving table form a triangle with two pounts
> fixed so they can be jointed together and then both put in a ball
> joint of some sort.
>
> Ideas appreciated, especially good ones.
>
> Cheers,
>
> Graham
>
>
>
>
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