4 bar mobile goal lift

How would you build a 4 bar mobile goal lift in such a way that the chassis can drive over the starting bar without the mobile goal lift hitting the starting bar?

just situate it on top of your chassis. when it reaches down it should lower itself but make sure there’s enough space for it to clear the edge of your frame

I would build it so that it sits just below your lift, or do what @Vyx did. Both work well.