Preliminary Design
During the prototyping phase of this project, the team brainstormed multiple mechanisms that would provide clean sweeping motions. The team determined that a figure 8 motion path would achieve the best results when cleaning a glass. To achieve this motion the team initially proposed a slider crank mechanism alongside a scissor lift to vertically move the slider crank. This slider crank mechanism would allow sponges to rotate in a circular motion, and the scissor lift will be synced to provide the desired figure 8 motion path.
Figure 1. Preliminary Design
Initial Prototype
While the preliminary design would achieve our desired motion path, the team decided syncing the slider crank to the scissor lift would be too complicated to implement. The team instead decided to opt for a geared five-bar mechanism. This mechanism uses two counter rotating gears couple with two connecting linkages. For our first prototype the team decided it would be best to start by printing the gears and linkages to prove that this mechanism would follow our desired path. A CAD model was designed for a gear with a 6 inch diameter with a 3 inch offset hole, where our linkage would be connected. Another CAD model was made for our linkages with a 6 inch hole distance. The team then laser cut two of each of these CAD models, and put together the first prototype shown in Figure 2 below. To assemble the prototype the team used 3 M3 bolts and multiple M3 nuts to ensure our linkages were properly spaced out. The gears were not initially grounded, but the team was able to prove that this mechanism would achieve our desired figure 8 motion path when the gears were rotated.
Figure 2. Initial Prototype
Final Prototype
(Changed link lengths, designed a base)
Figure 3. Final Prototype
Final Design
(Added Spacers, Connected Servo and DC Motor, removed front legs from base)
Figure 4. Final Design