ok for the ampersand.
For the angle limits in pin connection, this is exactly what my relations do but I set the min angle through a parameter.
As for the curve solution, can you move the chain on the fly if it is constraint on a curve ? I need to make an animation of a complete system so I really need to "mimic" the machine.
Back to my file, does it make any difference if you declare the part flexible before integrating it into an assembly (through "model properties"/"flexibility"/"change") or if you make it flexible from inside the assembly ?
thanks again !