Tinker - Document Tray Holder

This is going to be my first Engineering blog. To celebrate such an occasion, I've decided to start off with a true story: One sunny weekend a few months ago, I was diligently finishing my homework when all of a sudden, I realized that I still had more to do! Feeling very disorganized (or possibly disoriented from all the work I was doing), I made a trip to my local office supply store and bought myself this document tray holder. I soon filled it up quickly, classifying my three available slots as "Inbox", "Outbox" and "Scrap Paper". However, as ambitious of a student as I was, this was simply not enough! Soon I began my journey to increase the overall efficiency of my document tray holder.

For all my colleagues who might read this: don't laugh; the design process they taught us at UBC was actually helpful. Having said that, let's generate some "user statements" for my mini-project:
1) The current design is good, but I wish I could put more;
2) It takes up a lot of space on a tabletop.

Honestly, I made these up on the spot as I wrote this blog, but they're pretty accurate when compared to what I was thinking when I started this project. Regardless, these user statements translated to the following requirements:
1) The product has more than 3 levels;
2) The product can compact more documents into the same amount of space.

Functional Decomposition: Really the only function this thing has is to hold documents.

Brainstorming/Design:
So here is where the fun begins. After studying the original design of the document tray, I came up with a few ideas along the lines of expanding outwards, front and back, and up and down. In order to satisfy Requirement 2), I decided to expand up and down. However, simply buying another document tray and welding the two vertically together also violates Requirement 2). I figured the end result would look something like this:


As you can see, it satisfies Requirement 1) by adding additional layers to the top and bottom of the original three and Requirement 2) by inserting these additional layers shown in the picture (although the top layer exceeds the original design's height, it's still pretty close).

So the question is, how to fit these new slots given the original placing of the shafts? From the original image up top, you can clearly see that the shafts are located as 2 at the bottom and 1 at the top, effectively stabilizing the structure by triangulation. However, the single shaft at the top cannot hold any documents (unless you are really good at balancing things and your table doesn't shake when you erase) and the two shafts at the bottom interfere with any documents you might want to put down there (the clearance was actually 1 inch). So my modifications were thus:

Remove both the shafts at the bottom, and relocate one of them to the very back support. This effectively increased the clearance under the bottom tray to 2 inches:


Remove the top shaft, and relocate both remaining shafts to acceptable extremes of the top supports. The decision to place these along the horizontal support was made to maintain the maximum height (and thus capacity) of the top tray.

The final product looks like this:

As you can tell, my excitement in blogging this project eventually faded. That was also the same story with making this as well; there was a one month gap between completing this design and actually making it. Ultimately, I was happy with what I came up with though.

In closing, I do have future plans for another redesign, but it might only end up as bolting another tray to the top just to stabilize everything. The up side is that the first redesign reserves the foresight for that option to occur.

Thanks for reading! My old document tray used to hold three trays of paper labelled "Inbox", "Outbox", and "Scrap Paper". Now, my document tray holds five trays of documents labelled "Inbox", "Outbox", "Scrap Paper", "Empty Folders/Duotangs", and "Magazines I'm too lazy to read"...