[Mechanical] Revised Design

We learned some things from the initial design and printing.  As mentioned before, we knew we had to reduce the overall size from 1.75" x 1.75" down to 1.25" x 1.25" which has been done.  In addition we added a dual gusset support underneath the sample container to support the weight and any flex in the unit as well as add additional gluing surface area. 

One challenge that we have is that we have been unable to source a 360 degree servo and the current one that we have is only operable to 180 degrees.  One solution for this was to redesign the setup and move away from a direct drive system and toward a geared one.  The new design has the servo attaching to the servo arm as normal but then the arm is inserted and glued to a gear.  The gear will contact a smaller gear (at least 2:1 ratio) that will be connected to the top disk allowing for a full 360 degree turn. 

The black part is the servo with the white servo arm attached.  It is inserted into the semi-transparent gear (shown without teeth).  The yellow part is the top disk and smaller gear (again shown without teeth).  Finally, the red part is the modified base (sample container). 

 

After meeting with the group and discussing the design we realized that we need a way to keep the gear positively connected during the vibrations associated with launch/flight.  We decided that there will need to be a groove cut into the two gears and an o-ring strung around them to keep them from vibrating apart.  This will be reflected in future designs. 

 

Another issue that we are contemplating is whether the rapid prototype printer that we have will be able to handle the printing of the gears.  If not, we will have to source pre-made gears and attach them to the parts that we print.