Print this piece with no supports and break away the bottom rectangle and the center triangle where the chain would connect to. I created the supports so that slic3r doesn't have to.

This was a quick prototype, and it seems to work really well, the only thing is the first chain that is connected to the nema sleeve needs to be glued into a fixed position so that it rolls back perfectly straight depending upon your orientation.

I have uploaded the solidworks part file, i encourage you to make it better!