you could just put two nuts on the winged axle.
as they spin, they should travel in towards each other.
eventually, the nuts will get so tightly wound, that the threaded axle won't be able to move anymore, and the vehicle will stop.
or here's an even easier idea.
wound a rubber band tightly around a part of the threaded axle.
then get the nut on the threaded axle (position depends on distance that should be traveled)
and then have the axle spin until the nut is blocked by the rubber band.
i hope someone understood that.
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