I boys! I have two cubes.
one of these cube is a son of the other cube
I want that one cube will move only if the other cube has reached its maximum extension like a boom.
And at the same way I want the parent cube can move only if the child cube is completely shortened.
Any idea to do this?
Im trying to read variables from one script to another to import the value of Transform.localPosition.y that should work as a sensor that knows when a cube or the other must move
Sorry for the english and thanks
Have you checked out iTween its really sweet!
http://itween.pixelplacement.com/index.php
Then I would do something like
var boomSection1 : GameObject;
var boomSection2 : GameObject;
function Update ()
{
iTween.MoveTo(boomSection1,{"y": 2, "time":2, "onComplete":"Boom2"});
}
function Boom2()
{
iTween.MoveTo(boomSection2,{"y": 4, "time":4});
}
P.S. I really dig cranes 
sorry but I don’t understand. I need an Help with basic unityscript. I’m beginner
If you need help with basic Unity Scripting you can try these Then when you have a little more understanding you can move onto iTween which makes it even easier in some situations.
http://www.unity3dstudent.com/
http://walkerboystudio.com/html/unity_training___free__.html
and there is also the turboTwins on youtube
After you have a better understanding the script above will make sense 
I tryed it! but I believe it is an animation and not a movement by key pressing sensibility. I want to check frame by frame the elongation of the crane