KISHI QIANG
CAPESTONE PROJECT -- EASY CART
OVERVIEW
Team Project
Graduate Design Project
Carnegie Mellon Univerisity
Pittsburgh, PA
January - May 2016
MY ROLE
Research | Conceptual Design | Embodiment Design | Conceptual Sketch | Prototyping | Final Report | Final Presentation | Presentation Poster
SKILLS
Product Design Strategy | FMEA Analysis | User Research Skills | Rapid Prototyping | Solidworks | 3D printing | Machine Shop Skills | Material Selection Skills | Cost Analysis Skills
THE CHALLENGE
The aim of this project was to creating a new shopping cart which is light and foldable to a cuboid small enough to fit in a backpack. Our team wanted to make something for the people of our age. As a student not living with parents, we all need to do grocery shopping ourselves frequently and there is a big chance that we don't have a car. The design is different from the conventional "granny cart" (as shown on the right) in that it can be folded into a small size and only expanded into full size whenever needed.
The "Easy Cart" is supposed to save young people the trouble of having to carry all groceries in hand and make lives easier.
A GLIMPSE OF THE FINAL DESIGN
IDEA GENERATION
Our team broke down the whole shopping cart structure to several sections: folding mechanism, wheels, loading mechanism and braking system and came up with a dozen ideas for each section.
We also conducted a user research to find out what our potential customers want the most from our product.
CONCEPT SKETCHES
Since folding mechanism is the most important part of the product, we developed a more detailed sketch for each idea and evaluated them using pugh chart. We ranked each idea on basis of several critical criteria: folding and unfolding time, manufacturability, capacity, sturdiness and cost.
PROTOTYPE AND VALIDATION
Judging from the Pugh chart, roll-up mechanism ranked the highest among all options. We, thus decided to go on with this option and also started generating ideas for the other parts of the cart.
The sketches below show our conceptual design for the roll-up folding mechanism, handles and bags.
The prototype was mainly to demonstrate the folding idea given that foldable shopping cart is a relatively new idea so people might have difficulty to picture that without seeing a physical product. To reduce the complexity of manufacturing, we 3D printed all the side frames for the elastic string to go through and to attach the grid frame. For the handles, we dissembled two white canes and attached them to the main frame using bolts and nuts. The wheels were purchased as well.
FINAL PRODUCT
The “easy cart” is consisted of two main parts, the frame and the bag. To use the “easy cart, the user need to first unfold the base plates and put the cart on the ground. The wheels are fixed for now to ease the folding and manufacturing process. Then the vertical parts and the handle are unfolded in the same way that the tension in the elastic strings will pull up the plates and keep them in position. In order to keep things simple, we chose to keep the wheels fixed in position as opposed to having them rotate in order to accommodate folding. The idea of using elastic strings is inspired by white canes with the same mechanism keeping the cane straight. The structure will be like several rectangular plates with cylindrical tubes on the two sides with holes going through for the elastic strings. Lastly, depending on the material of the bag, the user will either zip up the bag (suppose the bag is made of canvas) or not need to do anything about the bag (suppose the bag is made of spandex)
STRUCTURE BREAKDOWN
USER INSTRUCTIONS
