Tree Squirrel Wind Sculpture

The second Mechanical Prototyping project challenged us to design and fabricate a wind powered kinetic sculpture. The final sculptures were hung up on light posts around Olin and displayed to the public.
Our team of 5 chose to create a bio-inspired project and designed a tree that changed seasons as the wind pushed the leaves around, with a squirrel popping in and out from behind the trunk. The rotation of the leaves represents the changing seasons, with brass autumn and aluminum winter.
I primarily worked on the squirrel mechanism, attempting to push the bounds of what I could do with sheet metal and four-bar linkages.

Design

It is notoriously hard to capture your sculpture working. You will have to take my word that there was a time when it spun majestically and faster.

The tree crown is an anemometer-like structure that harnesses the wind with curved leaves to rotate the main shaft.

Each leaf is riveted to the end of a copper rod, hammered flat, which screws into aluminum hubs on a D shaft. Each hub is offset by 60 degrees for a fuller crown of leaves.

To alleviate sagging, a bracket was attached to the front plate to brace it.

The sculptures were mounted onto light posts on Olin's campus.

The final CAD of the system.

A custom plant rack was welded to hold six pots of plants to add a splash of green to the bio-inspired metal.

The linkages were too long to support the weight of the squirrel, and the gear ration was reversed, providing a step up of 9:1 which caused the squirrel to violent jerk from side to side. We chose to remove this system for the final demo.

The sheet metal squirrel was fully CADed to use the drawings for manual fabrication.

All of the parts for the squirrel were hand-snipped according to the drawing.

The head, tail, and body were riveted together.

The sheet metal was bent using pliers to achieve the final shape.