I think I saw a rigging tool for that at creative crash once. Not sure, though. Other than that, I think this is rather complicated to rig, you could probably have a joint chain follow the whole spring till the ground and then try to drive these maybe with a bend and a stretch modifier (just brainstorming right now, I'm not even sure if that works) or even just an IK handle? that could actually work

Its not so complicated as it is time consuming. Mainly because of the weights. So, in this picture, the blue and red dots on the right are the joints, then the % numbers are how much that section of the spring should be weighted to each joint. This should be a smooth transition. very very smooth, going form 100% all the way down to zero when it reaches the next joint.



Thats just the very basic spring, if you wanted to animate it as a spine. But, if you want just 1 control on the top, then you`ll need to make the joint chain an IK solver with stretchy on it, and offsets in the middle. thats where it gets complicated.

Ummm, it might a little bit. fakepivots way certainly does. To minimize the stretch, you could put another joint where the 50% is, and parent constraint it to the red and blue, above and below it. Set the parent constraint to 50 / 50. Then instead of going from 100% - 0% from the red to blue, you do 100 - 0 between the red and new parented joint. if that makes sense at all.

Honestly, id just download one though. lol

Icwutudidthar

Create a nurbs spiral, skin that to a set of bones and then extrude a cirlce along that curve. It'll be easier to skin.

For the joints, create a simple IK spine setup with a controller on each end so each end locks down, and a controller in the center to adjust the curve.
Tons of tutorials for the spine I think, but none I can think of, off the top of my head. Essentially a splineIK with three clsters attached to control curves.
. It'll be a b*tch to animate but that's really it. Good Luck