limit configurable joint motion from 0 to +limit?

Hello,

i'm trying to achieve what is really on the headline. I know a configurable joint can be limited to a +/- limit amount, or be free for infinite motion on an axis. what i try to do is set a limit that will only allow from 0 to a limit or from 0 to infinity. Is this possible? is there a way to do that?

i already tried measuring the distance from my anchored object and give it a momentary thrust (it is a rigidbody) when the distance becomes < 0.1, but if the object moves fast enough it comes through the other side of the axis in one frame, measuring again the distance but this time the limit goes from 0 to -infinity. I need to limit it to only the positive joint X axis range...

thank you for your time!