I‘ve done some design changes after first prints of the gearhouse. I‘ve made a big error on my first design because there is no way to insert the roll gear 
I‘ve also done some changes on the gear for the yoke pipe and i guess there will be some more changes in future.
The printing time for the geahouse was 17 hours and some hours for the gears so i will need some days to print out all the party. I will post some pictures when the print is finished and put these things together.
I was thinkiong about your post. Yes, it could be happened that the Roll Gears will move away from each other when the Yoke is rolling to the right. I will test it when the prints are finished. If it’s happened then it coul be a solution to add a second roll gear on the right side, but only the left side is motorized.
Like this:
