I got the inspiration for this lift after seeing Alocke's ball machine Tartarus. As you can guess by the name, when the car gets up to the top it suddenly free falls. This is do to the special gearing mechanism. I modified a medium knex gear by taking off some of the teeth leaving only 17 left. When the teeth of the medium gear catch hold of the small gear (see picture 10) it turns the shaft which is connect to a wheel-like device which winds in the string (or chain) connect to the car thus pulling the car up. When the car gets up to the top there are no more teeth turning the blue gear thus making the car fall. Enjoy the video.