Hi L,
It depends on how you want the ‘rubber strip’ to behave during animation but I think your best option is with an IK setup.
Either a normal IK or with a spline IK.
From your sketch it looks like the rubber strip will just fold around onto itself kind of like it is a clam shell so a normal IK would suffice.
Start the rigging with all the parts straight (not in the final position)
Then create a chain of bones for your rubber section (this will be the IK section), Parent the start to a bone that deforms “A” and then create a IK target to a bone that deforms “B”. (All your bones can be part of the same armature but make sure the IK target is not parented to any bone in the chain.)
Make sure you weight the bones. You probably won’t need a pole target if it bends like your sketch however if you build the IK chain perfectly straight it won’t know which direction to solve so introduce a small bend downwards in this chain.
I hope that makes sense – let me know if you need more help.
