Cybersonics used the van door motor to drive our telescoping tower last year. We had it driving a linear chain attached to one section. There is a little info on it in our
2004 Inventor submission . There are a couple of animations at the bottom of
this page which show how we used it, though not in detail. There's also a video of it
working.
We put a 20T sprocket on the motor shaft, driving a 38T intermediate, connected by a shaft to a 24T which drove the linear chain. The linear chain & sprocket worked just like a rack and pinion, except we wrapped the chain half-way around the sprocket.
In this configuration we could lift the robot at about 1 ft/sec, and were able to llift ourselves with two other robots part-way on us. The tower drive was one of the most reliable parts of that robot. In testing it lifted over 200 lbs. Which, btw, is way beyond what the FIRST torque specs say it should be able to do - by a factor of three!