Gear Ratio

The primary module that I worked on was the transmission. After prototyping several methods, we landed on a stepped pulley drive. This enables kids to have both a visual and tactile interaction when adjusting the speed of the car.

The pulley drive is coupled with a cam-actuated tensioning system, embedded in the lid. When the lid is opened, the pulley cones slide together, creating slack on the belt. The belt can then be easily repositioned to select a new gear ratio and tension can be reapplied by closing the lid and sliding the cones back into place.

Suspension

The suspension module was implemented in order to teach the concept of spring force. I designed the notched slider and complimentary thumbscrew in order to make it easy to change the handling from rigid and responsive, to loose and bouncy.

This module was particularly tricky because it had to mount to the preexisting chassis and interface with the existing suspension system.

Interchangeable Tires

The final module I worked on was the tire fastening system. The tire module includes several tires of various sizes and treads that can be switched in and out to adjust the car's handling.

In order to facilitate this, I designed thumb screw caps to press fit onto the tire fasteners so they could be turned without a tool..