To begin prototyping, we started with laser cut cardboard, cut to the same dimensions as the final product. Our other parts (the base & support) were not geometrically complex, and those were easily modeled. For the gears, we were able to use Solidworks’ gear toolbox, which easily creates gear models all we needed to specify were the necessary gear dimensions, such as diametral pitch, number of teeth, width, etc. We first modeled all of our parts in Solidworks to check if we could integrate the parts easily. We proposed the idea of having a slot that will fit the handle of the arm, restricting the handle to vertical motion. We did some research, finding real world examples of sun-and-planet motion notably, the Whitbread engine, one of the first rotative steam engines ever built. At first, we didn’t know the best way to mount the arm that is attached to the planet gear. The underlying principle of sun-and-planet motion is that it converts linear motion to rotational motion.
It consisted of a horizontal base and a vertical support, with the sun gear mounted to the vertical support and the planet gear free to rotate around the sun gear. We began with a rough sketch of what our design would tentatively look like. Conveniently called sun-and-planet motion, we had the idea of our design depicting the Earth orbiting the sun. We wanted our design to be space-inspired, and after browsing through all of the different movements, we decided to base our design on movement #39, which consists of one spur gear revolving around a fixed spur gear.
This project was intended to allow us to use all of the tools and skills we had learned up to this point.
For the final project, we were tasked with designing and constructing a mechanical model based on one or more of the movements in the book 507 Mechanical Movements.