Renee and I tackled modeling a bell tower for our midterm project!
Initial Ideation
Our first challenge was to break down a real-sized bell tower into something we could model. Bell towers have many parts, as shown below, and we needed to determine which parts were necessary for them to function.
From diagrams like the one above, we determined that the wheel, rope, and bell were the main, essential parts that define a bell tower. We also determined that the garter hole, ground pulley, stay, and slider were also desirable, if not essential, to bell tower function by watching videos on how they work.
Low-Fidelity Prototype
Our first step in prototyping our bell tower was to draw the files we wanted to cut on Illustrator, as shown below.
There were four main components: a display box, the pulley and its box, the wheel, and the stay/slider mechanism. We laser cut this file out of cardboard, and then assembled our parts using school glue and tape.
Through this low fidelity prototype. we found that the general arrangement of our parts would work. However, we were unable to confirm if the model would function because we did not attach the bell and there was considerable friction between the moving parts.
Medium-Fidelity Prototype
Our main goal for the medium-fidelity prototype was to test if the model would work. We also wanted to implement close-to-final design changes, such as adding a tower. Similarly to our workflow for our low-fidelity prototype, we started with drawing a file on Illustrator, as shown below.
We cut out this file from wood and assembled the parts using wood glue. We also attempted to lubricate the dowels using graphite powder in order to reduce friction of the pulley and the main dowel attaching the bell as much as possible.
Through this prototype, we demonstrated that our two dowels — one for the wheel-bell-stay components and the other for the pulley — did work. However, we had difficulty getting the bell to do a complete turn to the other side of the slider. We also found problems with the bell’s clapper (internal ball that makes it ring!) folding over itself when it swung.
High-Fidelity Prototype
Our main goals with our final, high-fidelity prototype was to address the issues we saw in our medium fidelity prototype and to complete post-processing and finishing. Again, we started with a revised Illustrator file, as shown below. We added a name plate and edited the sizing of other components for better fit and aesthetic.
We cut out the file using wood and before assembling, we post-processed and finished the laser cut pieces by sanded them and applying a wood stain, as shown below with our name plate.
We also used the water jet to cut out our slider. We sanded, wire brushed, and sandblasted our piece, using a vinyl mask to display “ENGI 210” on the piece, as shown below.
As a last step before assembly, we fabricated a new clapper by twisting a paper clip into a sturdy shape and then gluing small laser cut pieces to prevent it from folding over on itself, as shown below.
Finally, we assembled our bell tower, gluing our pieces together and applying the graphite lubricant to our moving pieces. We also added springs using epoxy in order to help the bell swing completely around.
Here is our final prototype!
Cost Breakdown
1/4″ 48 x 96in Plywood: $29 (Home Depot)
1/8″ 12 x 2in Aluminum Sheet: ~$3 (Amazon)
String: negligible
Bell: $6 (Michaels)
Wood Stain: $8 (Amazon)
Labor (2 people x 20 hr x $10/hr): $400
Total: $446
