MECHANICAL ORRERY - TRANSLATION AND ROTATION.

MECHANICAL ORRERY

I present a representation of the Earth and Moon's translational and rotational movements, created especially for children. Thanks to its robust structure and simple mechanism

The project has two options, one without, and one with AMS. In the first, you should print:

• Mechanisms and base in grey

• Sun in yellow

• Moon in white or grey if preferred

• Earth in blue. In this case, the continents have some relief, and should be painted with acrylic or a permanent marker. Otherwise, its rotation movement will not be appreciated

In the second option, we will consider the following particularities:

• Earth. It has its own profile, with variable altitude lines, for which blue, brown, and also white color are needed

• Remaining parts are together with the rest of the elements (except the earth) in a single profile, for which we will need: Yellow for the sun, grey for the base and mechanisms, and white for the moon

In this model, the sun is different from the previous one, it is larger, and only its upper half is printed. Which we will mount on the board of the months of the year                   

MATERIALS:

I personally recommend printing the project in PETG, as the parts undergo stress with movement, and PLA could break

ASSEMBLY:

No additional hardware is needed for assembly, but contact adhesive is recommended

PRECAUTIONS:

Although the design is intended for children, they must be of an appropriate age to handle it, as some of the parts are small and could be swallowed. I recommend that the mechanism always be operated by an adult, and that children never be allowed to use it alone

ACKNOWLEDGMENTS:

This design is the product of a long search for a suitable model for primary school children and the printing of some of those available online. And the fact that none of them, in my opinion, met the characteristics that a model comprehensible for early ages should have. For this reason, I finally decided to design my own, and although the model, in my understanding, cannot be considered a derivative, I would like to acknowledge that for some of the elements, or for the general operation, I have been inspired by existing ones  

Three-sphere Armillary (no hardware needed) - Free 3D Printed Model - MakerWorld

Simple Earth Orrery - Free 3D Printed Model - MakerWorld

Additionally, for the globe, I have used a Thingiverse model with a very permissive license. This model was an STL, and it presented difficulties for coloring, so I have removed all the mesh except the relief of the continents, I have added a sphere inside it, and I have transformed it into an .obj to easily add color. I have also added white polar caps. Its link is: https://www.thingiverse.com/thing:5424258. I thank its author for sharing it