Product Development - Summer 2022
Collapsible Sofa - The Suite Case
As the name implies, this project aimed to prototype a collapsable loveseat, focusing on the aesthetics matching those of traditional furniture. The project has concluded, with me having led a team of four UC Berkeley students through the various stages of product design and development. See Final Report of full documentation.
Market Need & Design Criteria
Everyone on our team has experienced the stress of moving, which has led us to come up with our product, the Suite Case, a lightweight collapsible couch. Our couch is ideal for college students because it is built to be comfortable and durable, yet able to collapse into a smaller piece of furniture for transport. The primary design criteria was, (1) compactness for transport and storage, (2) lightweight for moving, and (3) aesthetically pleasing. Each of these feeds into the core objective, a couch that is easy to reuse and hard to abandon.
Design Iteration & Design for Cost
While working on this project our team considered many approaches to satisfy the three design criteria. Predominantly we began shifting our focus to designs which featured a centerfold, moving from an M-fold concept to a W-fold concept, before finally settling on an A-fold concept.
Once we had agreed upon the A-fold, the design had to be reworked to align with our relatively low budget.
M-fold (open)
M-fold (closed)
W-fold (open)
W-fold (closed)
A-fold (open)
A-fold (closed)
A-fold DFC
(open)
A-fold DFC
(closed)
Critical Failure Mode & FEA
Before we began assembling the prototype, we found it necessary to examine the relative stability of the most contentious element, which differentiates this sofa from a regular sofa. The relative stability at the center linkages at the bearings.
A normal sofa will include a continuous beam or some material along the length, with no legs supporting the middle in most cases. For this reason we chose to consider the case where we did not incorporate center legs to better distribute the weight.
To do this we started by constructing a FBD to estimate the tension that would be transferred at each bearing, finding that the tension is proportional to the total weight of occupants and the sofa, proportional to the length of each half of the sofa, and inversely proportional to the distance from the bearing to the top surface of the sofa.
The sofa without the center legs, was shown to have a safety factor of 5.44 for two 250-lb occupants. We decided on keeping the center legs as it would likely be necessary in any second generation due to the before mentioned dimensional proportionality.
See Final Report for more detail.