I'm taking a Product Design class and recently finished working on a prototype for the mini-project. The assignment was to come up with a concept and prototype for a simple product that is easy to manufacture, and designed for college students. Each of the 60 students pitched an idea to the class, then after a round of voting, the top 50% of the ideas were further developed in teams of two. This was my initial pitch to the class:
The concept was a credit-card sized tool that consists of four 3-inch pieces of plastic with elastic joints, allowing them to be clicked around into a 12" ruler. The tool was designed for people who need a good straightedge and measuring tool on the go. The elastic bindings let the user also set the tool up with right angles, to easily draw boxes and corners. After the voting round, my friend Jon joined my team and we threw around some other ideas:
One of the problems with the elastic band design is the actual construction of the parts. If the individual pieces have closed holes, it would be impossible to thread the elastic loops through. If the pieces were notched rather than having holes, we could slip rubber bands on, but the whole thing could fall apart pretty easily. Eventually, we came up with a puzzle-piece design, where the pieces snap into each other. We figured out some numbers, bought some acrylic, and popped it in the laser cutter.
This little card has some pretty nifty features. Once the pieces are snapped out of the end piece, they can be clipped together in various ways to make use of the different drawing features. The first two pieces can be used as a protractor (which can be extended by adding any number of pieces in between). The third piece can be combined with any other to make a right angle. And all four pieces can be connected in a line to make the full 12" ruler. The pieces are a snug fit, and hold together pretty well.
When we made up the designs, we laid out six versions of the same set of parts, all with different offsets to account for the laser's kerf. By varying the fit by thousandths of an inch, we could find a nice tight fit that would still allow easy use.