Supporting a pop up roof - examples or methods?

When several teeth broke off the crank and lodged in the rack while I was raising the roof, the mechanism jambed and wouldn't go up or down. I had to jerry-rig some way to lift the roof to take the weight off while I cleared the metal chunks from the rack. An old fashioned bumper jack, a section of 2 inch PVC pipe, and a 2x4 with a dowel in the center to fit into the PVC solves this problem. Position the jack so that the board lines up with one of the frame members in the roof.
Tom McCloud