Arch 433: Caleb Scherf’s Studio Project
Course: Arch 433
Students Involved: Caleb Scherf
This realization led me to look into other expandable designs for precedent. In searching I found the Hoberman Ball which solved almost exactly the problem I was investigating. Using a series of scissor hinges arranged in a particular way, the Hoberman Ball creates a sphere that can expand greatly in size. From here I decided to create a much simpler form using a similar scissor hinge mechanism that could expand in one dimension using a single repeated hinge.
Beginning design I first laid out the rods to determine exactly how many hinges I would need and how many types of joint would be necessary. It became apparent that by creating a pentagon of single crosses I would only need ten identical joints at the corners to create the desired form. My original plan was to use ball and socket joints at these points and to allow for the rotation around multiple axis as the hinges spread out and rotated as the pentagon expanded. Through some experimentation though I realized that this was actually not necessary, and a simple pin hinge rotating on one axis would allow for the correct rotation.
I decided to attempt to print each hinge together because the layered nature of how the 3D printer builds parts and small scale would allow the pin of the hinge to be built through a gap in the opening of the other half of the hinge with no assembly required after. I modeled the hinge in Rhino and made my first print attempt where I discovered my first issue. Even though the printer is very accurate, the tolerances on digital were too tight and the two halves printed together as one piece. The worst of the joining was at the pin itself because the slight sag in the plastic as it bridged the gap connected it to the bottom of the hole of the other piece. I then adjusted the model to increase space between all moving parts as well as rounded out some edges to reduce volume and potential collision points. This print also showed that the size of the holes for the rods would need to be increased to fit them easily.
The modified hinges printed perfectly and I was able to assemble the whole form. It was at this point that I realized that without anything to hold each cross in the scissor jacks together, the form was unstable and difficult to work with. This problem was solved by creating small collars that could slide onto the middle of each rod to act like another hinge. These also required two prints to get the tolerances just right to allow them to slide into place but still hold firm enough in their place when assembled and moved. Once fully assembled I discovered that a little bit of extra space between the collars and rods allowed them to move up and down, moving the hinge point and adding another level of flexibility to the overall form.
January 31, 2018 5:48 pmShow all architecture projects