There are many ways to rig one thing in 3D, and here Rigging Artist Arun Lingasamy shares one technique for creating a rig for a spring in Autodesk Maya. Quite often something will look simple, as in the case of rigging a spring, what you want is a scaling action along one axis, but doing so will also scale the form of the swept shape that makes up the spring.
A new way to rig spring in maya
Here, Arun Lingasamy shows how to make all the proper connections, and shows how to use a joint for the scale action, and sets everything up into a easily created and usable rig.
For a more in-depth look at the underpinnings of creating accurate spring rigs in Maya, Paul Atkinson offers a comparison of rigging techniques side-by-side complete with loads of nerdy code. Comparing Techniques for Rigging Accurate Working Springs in Maya.