The Eggcrate Center Ankle

I have designed a center ankle assembly built using an eggcrate frame for the non-structural parts of the ankle structure. Because I'm not comfortable with the idea of tapping threads into styrene, even though I've done it, I incorporated a barrel nut (sometimes called a dowel nut) into the structure to anchor the ankle to the frame.

This is the full center ankle (with only the edge skins missing)

The image links to a 3d pdf file, click on it if you want to be able to rotate the image around and examine it from other angles. (Note, the 3d.pdf file opens in a new window. If you have problems with the 3d feature you may have to upgrade to the latest version of Adobe Reader).

After 'activating' the 3d mode by clicking on the display
select a part by left clicking on it (the part will be highlighted)
then right clicking brings up a window.  Follow the sequence
-> part options -> part render mode -> transparent
to make the outer parts transparent and the inner
details visible.

Or you can use the views below which also link to .pdf files.
This is a partial view of the center ankle with parts made transparent so you can see the barrel nut.

The image, like the one above, links to a 3d pdf file.

As with any design, there are limitations to what can be reasonably accomplished by CNC machining.  You might have noticed the red lines in the curved part with Skin drawing above. Those are the edges of the ribs 'sticking' thru the skin. I had a choice. I could make them the hight of the rings but then you'd only get support on the edge. Instead I made them higher. They will have to be filed down to match the contour of the rings. See the Assembly Instructions for the highlights of what you'll have to do by hand.

The design drawings are available as both Autocad .dwg files and Adobe .pdf files download drawing files with the understanding that the drawings are copyright to Media-Conversions and are not to be used commercially. (That note also appears on each of the drawings). I've also put together a set of assembly instructions to help you put the legs together. Don't want to cut your own? You can try this parts source.
Please use the Contact Form to send me comments, questions, or suggestions on making the design better.