http://www.youtube.com/watch?v=paTfImOEyps
Test thats part of a bigger project, but I was pretty pleased with the results so I decided to post just the rig as well 
really nice movement you got there!
WOw. I like that stuff! Any chance you can make a detailed tutorial how to make hydraulics/mechanics like this?
Yeah a tutorial or simple step-by-step would be awesome, the result was pretty damn cool, good job!
Well done !
It reminds me of this suspension rig here that i’ve worked on from a Wereaser file.
Any chance to see the rest of the rig soon ?
Nice suspense rig. I dunno how soon the entire rig will be made. I’m just making it in spare time. as to the rest, I’ll see if I can throw together a decent tutorial.
Alright TUTORIAL
Four seperate objects. top tube, bottom tube, top circle, bottom circle.
Line em up like so:
use the center cursor button on all the objects (Editing menu, mesh tab) , and then position the tubes rotation point at the center of the circle they are touching. parent the tubes to the circles they are touching. (ctrl P) make sure you parented it properly by moving the circle and seeing if the tube follows with. now, for the top tube add a constraint, “track to” and make the track to object, the bottom circle. the settings you need below that are To: -Z Up: X.
For the bottom tube, Track to the top circle, settings To: Z Up: X
okie dokie, pull one of the circles with the arrows to the right or left or down or up. it should be a working system now. if you want to keep the tubes from sliding out of one another, try a limit location function and toy around with the settings until your happy. if you want to get really fancy, duplicate two or more of them and line them up however you like, making an armature, and then parent the circles to the armature bones they should correspond to.