My final project is a gravity main drived car, I design the structure by 3D model design software CREO. It have almost 33 parts.
3D Model Design
Parts Download
I change the turning method, at first the turning was execute by a linkage. And in my final project a sona detected the descending distance and this distance conrolled a servomotor which makes the car turning. I decided to make the car by laser cutting and 3D printing. It will cost a lot time if I print all of the parts. Laser cutting can save many time, a cutting file need be designed.
AutoCAD 2014 was used for designing the cutting file. The car arrangements was show in the picture.
Another view angle of the arrangement. When the weight falling the winding roll will rotate, the big gear rotates with the roll at the same time. The small gear will roate so the back wheels will rotate then the car moves.
Front wheel sets, servo make the wheel turning.
Pulley was used for it can decrease friction.
All the parts were designed the size and shape were showed in the picture below.
Desgin file download