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Unread 09-01-2005, 21:13
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petek petek is offline
What would Dave do?
AKA: Peter Kieselbach
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Re: Inventor Tetra Connector

I've attached our TH Connector Inventor part. I had to move the End of Part marker in the browser to get the file size below 100K. When you open the file, drag the End of Part marker to the bottom of the browser and save the file.

It took a little thought to lay out, but if you do it the way Inventor wants you to, it isn't all that hard - just a little time consuming. The way I made it I was able to fully constrain the tetrahedrons to the connector using Insert constraints for all but the very last mate, which I used a Mate of the hole centers for.

To make the connector "clover" I followed this procedure:

Use the Sheetmetal template and set the thickness to .098 (in Parameters).
Start by drawing the 2.55 and 1.25 layout circle constructions. I recommend using the Fix constraint to nail down the origin of these circles at the origin of the sketch axes.
Then draw construction lines at 30, 90 and 150 degrees, intersecting the origin.
Draw the top "petal" 1.95 circle at the intersection of the 2.55 circle and the vertical axis.
Next, draw a 0.093 circle at the intersection of the 30 degree line and the 1.25 circle. Repeat on the other side at the 150 degree line.
Draw a line tangent to the 1.95 petal and the 0.093 circle.
Repeat these steps for the other three petals.
Trim the "extra" from the 1.95 and 0.093 circles.
You should now have the outline of the part.
Draw the 0.375 hole circles.
Exit the sketch and save your work.
Use the Face feature to "extrude" the sheetmetal thickness. If this fails, go back in the sketch and make sure you can close the loop.
Create a new sketch on the face of the part and draw the fold line as shown in the PDF.
Exit the sketch and use the Fold feature tool to make your bend.
The 35.3 degree dimension on the PDF is rounded from the delta/2 (=arccos(1/3)/2) If you want your connector to mate to the tetrahedron ends, use 35.26438968 (or enter the formula in Parameters, like I did) - otherwise you'll get constraint errors.

By the way, check out Math Forum's Tetrahedron info for the formulas for this beast.
Attached Files
File Type: zip 2005-Arena-TH Connector.zip (81.8 KB, 165 views)
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Pete Kieselbach
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Last edited by petek : 09-01-2005 at 22:50.