Casual Commuters
Backpack Platform for Bikes
The Challenge: Develop a system for carrying a backpack on a bike so that the user doesn’t have to wear it while riding. Make it durable enough to withstand daily commuting use, but affordable enough for lower income demographics, such as students. Develop product through engineering validation, design validation, and product validation stages to be ready for mass manufacturing.
About:
Based on our team’s personal experience as cycling students, we found that commuting with a backpack pit strain on our backs. It also took the fun out of the bike ride. Based on our research, we found existing product solutions to be expensive and homemade “milkcrate” to be unsafe and bulky. We set out to make a cheaper, better solution.
My Role:
Prototyping, CAD, Fabrication, Lead Test Engineer
Team:
Carly Buchannan, Emerson Daigle, Cooper Pursley
Sketch of “Milkcrate” Concept
Sketch of Rigid Hinge Concept
Sketch of Sushi Roll Concept
Proof of Sushi Roll Concept
EVT Prototype
Process:
We started with many concepts including a rigid hinge concept, a better “milkcrate”, and sushi roll concept. Through testing we found that the sushi roll to be the easiest to take on and off the bike while still being compact enough to fit in a backpack. This was a key criterion of our design as it was essential to bring it on the go.
After down selecting to the sushi roll, we conducted a failure mode and effects analysis and iterated through many prototypes to tackle the key risks. We needed to ensure that the rivets were mechanically strong enough to hold assembly together and that the straps would stay taught around the bag during loading and vibration while riding. Throughout prototyping we refined our manufacturing process to ensure proper assembly and reduce rework. We also created an assembly fixture to hold all parts in place to accelerate assembly time.
DVT Prototype
Result:
The result was a lightweight, packable platform that reliably held 50-pound loads and fit in a typical water bottle pocket. We quickly made 6 identical platforms thanks to our refinement of the manufacturing process.
This product validation testing (PVT) run was the end of our product development, but we developed a full bill of materials (BOM), and calculated the tooling, non-recurring engineering costs (NRE), and cost of goods (COGS). After this PVT run, the platform was ready for mass manufacturing run.
