Ashley Lowber
Mechanical Engineering Portfolio
My inspiration behind using the rack and pinion as the basis for the design came from a curiosity to find a motion that could incorporate simultaneous linear and rotary motions in a life-like scenario. I considered that it would be interesting to experiment with partial rotary motions as I brainstormed my product, and was ultimately influenced by the biomechanics of dog tails. Utilizing the rack and pinion mechanism, I incorporated my creative skills to design my product as an interactive display piece. The piece is constructed mostly from laser cut wood, and from the side, the symmetrical dog-shaped walls align. From the front, the user can move the collar back and forth, and from above the user can view the gear-based mechanism.
Laser-Cut "Dexter" Dog
The Process: Idea and Sketches
My inspiration behind using the rack and pinion came from being curious to find a motion that could incorporate simultaneous linear and rotary motions in real life. As explained above, instead of my product being solely a mechanism, my desire was to have it mimic an action that occurs in real life. As I considered what to build, I thought it would be interesting to experiment with rotary motions that not completely circular. I thought of playing with my dog back at home, and how his tail excitedly wags in a rotary motion when I move a toy or bone in front of him. This action satisfied my objective to create a real-world experience with the rack and pinion mechanism, while utilizing my creative skills to form it into somewhat of a toy.
From Rapid Prototype To Digital Model
My rapid prototype confirmed that I would have to employ the use of a platform to stabilize the gears and limit the motion of the tail mechanism. As shown in the first image, without a platform there was no way to ensure that the gears would be limited enough in movement to keep the tail at the posterior end of the structure. As I edited my design, I used Illustrator to trace the semblance of dog, and exported this design into CAD software to create symmetrical walls. From the front, the "Dexter" dog collar would be on display. This tag would be able to be move linearly to activate the chain of gears and create a rotary motion of the tail at the posterior end of the structure. Using the assembly feature in CAD, I was able to model this motion in the software before final construction.
Final Product
Overall, I am very pleased with the final result. The walls outlining the dog came out very clean, and the structure was able to stand due to its symmetry. If I had more time, I would have covered the gears with a plank of wood that would have formed the dog's back, and, I would have like to add a removable wall to serve as the dog's back.
One of the difficulties I faced was in creating a series of gears that moved effectively together and without creating too much friction against the plank holding them up. In the future, I would have done further research about gears, looking into more than simply standard gear ratios. This would have helped with achieving the perfect pacing between the gears, and advising about how to reduce friction. Though I mended the friction problem by using washers below the gears, I would like to add longer nails and nuts to stabilize the washers further.
