[mathking]

We built our first prototype with a window motor. Worked great until we weighted the bridge. Then we went to the gear motor. Better but still the same result. So we did a 3.5 to 1 reduction (via chain) and it seems to work now. There is a roller made of delrin on the end to allow it to roll on the ramp surface as we drive forward. We have not been to a regional to test it yet, but since our manipulator will lift the front of the robot off the ground, if it does not push down the bridge making it stronger won't help.

We too waited longer than I would like to get a working prototype, but we did plan for how and where to mount it. We are using a couple of pieces of 1x2 tubing (with slotting to reduce weight). One as a the arm and one as a mount for the arm and motor. One thing we did decide on early was that our design should be able to both push down and push up the bridge.

In any event, the whole assembly weighs about 4.8 pounds, and is one unit. So it just takes four bolts and quick connecting the wires to mount it.