Something Big: An Extending Furniture Object

My original idea was to make a chair that could be extended into a bench. I wanted to use scissor-like extension. In the process I (i) wrote a small Mathematica package the implements math string-style plotting, (ii) experimented with Inkscape (iii) made a cardboard prototype and a wood prototype based on different concepts, (iv) partially completed the full-size version using the ShopBot to cut plywood.

Math Strings in Mathematica

Here is a Mathematica package I wrote to do 3-d Boolean function-based modeling.

Inkscape Experiments

Below is an initial sketch for a chair profile that I sketched in Inkscape using Bezier curves.


I made a cardboard prototype using a vertical-planar scissor design. This concept was limited by the fact that increasing the range of the scissor motion beyond a certain point weakened and eventually severed the geometry of the part.

The wooden prototype was the same as the final design. However, I choose the tightening parameter to be slightly too large, so that the parts had to be hammered into place. Needless to say, the prototype has limited flexibility. Importantly, however, the prototype proved that the design can be constructed with rigid parts using locking and rotating actions.

Full Size Parts

Although I did not complete the full-sized furniture object, the principle has been demonstrated by the parts that I have constructed. In fact, the only thing missing is more copies of the parts that I have already made.