[petek]

This movie shows as far as I got with this problem. The links are actually constrained tangent to a hidden chain path (like J's famous "chainer"). It would lock up with more links and also when the three links got to the end of the straight path and tried to transition to the curve on the left end.

The links are actually "pulled" by a hidden block which is constrained to the path and is moved by the animator dial. Without the chain links holding it up, it would follow the whole path around.

This was done in Inventor 6 a couple of years ago, btw.