Holy Grail – Collapsible, Sustainable Cup

Solution

Introduction

The original basis of this project was a brainstorming exercise that consisted of photographing every item I used throughout an entire day, and seeking a seed from which to improve a design. The results were quite depressing � much of what we use is thrown away, and most of that is the packaging of foods and liquids. Coffee and take-away beverages were especially responsible for this, despite the fact that drinks like freshly made coffee are not, by nature, pre-packaged. Thus it became my goal to create some form of drinking vessel that could mitigate the harm done by our drinking habits.

 

Brief

Clearly, there are many excellent reward/acknowledgement system ideas already out there to encourage re-use of personal cups, but I found that a fairly unexplored niche was the reason why these great concepts are not commonly employed already, and have not been especially popular in practice. Why is that? For one thing, while this competition is rightfully considering coffee cups, how many other drinks are there that people consume each day? I know I�m guilty of drinking a lot of soft-drinks and bottled water when I�m out, simply because I don�t have my own cup � so perhaps having a cup design limited to a specific coffee vendor is imposing artificial functionality limits. More importantly though, was the simple reality of the scenario. How many of us are willing to carry around a big mug, whether we get rewarded or not? After all, that�s the whole rationale behind disposable cups in the first place. So, compactness and user convenience became my driving motivation, necessitating a shape changing cup, and opening a whole new can of worms.

 

Design

As you can see in the images, the result, after quite extensive experimentation, is fairly unusual looking. Problems with traditional compact cups are that they lack the structural rigidity of one-piece cups � if you want something to flex or pop open easily, it typically closes or collapses easily too � not fun with scalding liquids. The design I eventually settled on uses the �living-hinge� properties of recycled polypropylene, combined with a modified �miura-ori� folding technique (researched by organisations such as NASA to deploy compacted boom arms in space). The structure, which is mathematically derived from bending reactions in a cylindrical object, means that the cup can extend, through a twisting motion, from a tiny 10mm thick storage state, to a much larger shape, capable of holding 380ml, or a large coffee.  Moreover, the shape naturally has to mildly distort the material in transitioning between collapsed and open, so it naturally holds itself in either state, and unlike simpler circular distortion designs, using elastic materials, it has an extraordinary level of lateral rigidity, even with little or no liquid inside to create pressure (meaning your grip can�t crush it). There are a few other advantages to using polypropylene as a material, which fulfil my initial sustainability requirements. For one, it is the second largest polluter plastic (even worse than PET), so by recycling it in a cup, you both reduce an existing waste resource, and eliminate another entirely (disposable cups). It�s also dishwasher safe (high-melt point), unlike many bio-plastics, and has an exceptionally easy to clean, hygienic �waxy� surface. It also goes some way to protecting the hand from coffees heat, which is aided by the very small contact area the folds create with your hand. At the end of its desired life (indefinite � folding creases in polypropylene do not wear out), it is simple to just recycle 100% of it again into lower grade products. A strap attached to the top holds a cap, so that the closed item can be put in a pocket without leftover drips. This strap serves a dual purpose � in closed form it wraps around the cup to ensure it stays closed (and can additionally hook the cup to a belt for those without pockets or bags), or in extended form it can be reversed to act as a carry handle (carrying many cups at once from the top like shopping bags is much easier than balancing several from the base).

 

Future

My design is presently in the initial stages � prototypes have been made (demonstrated in the pictures), but there are some ongoing modifications to be made. For the cup to sit well, and close better, the base and top will be developed into thicker shaped items, and if the cup was to be produced in any significant numbers, it could easily be blow-moulded like water bottles, so the technology is there. My current version was hand-made, the process for which I put on Instructables if anyone is interested in making a rudimentary version themself: http://www.instructables.com/id/Holy-Grail-Project---Re-Usable-Collapsible-Cup-fro/