Tuesday, April 22, 2014

Board Fabrication

The next step is fabricating the actual pivot board. Since the mounting holes of the rear wheel power train of the scooter has two levels, one set above the wheel and the other above the motor, the board also needs to have dual levels. Our initial deign is shown in the SolidWorks model below.
We cut a large plank of plywood into one square with center cutouts for the wheels, a center support piece with wheels cutouts and a solid center support strip to cover the wheels. The two central pieces were mounted to the main square board using  12 30mm bolts spaced over the center strip.

Originally we planned to mount the 12V Lead Acid battery to the top of the board but for weight-balance reasons and fear of tripping over the batteries choose to mount the batteries to the bottom of the board. Cardboard wrapped steel cables were used to mount the batteries to the bottom of the board and 2 inch nails were used to keep the batteries from sliding around. The motor controllers were also mounted to the bottom of the board using mounting tape and lots of gaffers tape. Below is a picture of the mounting arrangement on the bottom of the board.

The rear wheel power trains from the scooters are outlined in orange, the batteries are outlined in green, and the motor controllers are outlined in red. Lots of tape was used to secure the controllers and loose wires from the batteries and motors.

To keep the rider from tilting too far over and rubbing the edge of the lead acid batteries across the ground, we nailed in three layer slabs of plywood to each end of the board. A thin layer of packing foam was also tapped to the top of each wooden "tooth" to pad the tops of the wooden teeth.