I. Proof of Concept Model

Proof of Concept Model Design

To test our two linkages, we constructed a low-resolution prototype of both the Geneva mechanism as well as the four bar straight line Hoeckens linkage.  This was our initial experimentation with using fused deposition modeling as well as laser-cutting acrylic. 

Manufacturing challenges were seen in the use of the 3D FDM printers in the UT Maker Space.  Even small components can take quite some time to build, and multiple attempts are usually necessary for usable components.  The biggest challenge of using these machines was holding tolerances, as we planned to affix our Geneva driving wheel to a rotating shaft with adhesive (as keying was not an option).

Straight-Line Cutting Mechanism

The goal for our cutting motion was to achieve a straight-line cutting stroke followed by a reset stroke that would be back to the original position. A key component to this design was the cutting stroke; there had to be enough clearance so the bread could pass under the knife as it rotated on the cutting platform. Below is an image of the output motion (in black) modeled after Hoecken's linkage. As you can see, half of the output movement is a straight line while the other half is the reset. 

Cutting_Motion.pdf

Links in .pdf

• Red = Input Crank 
• Blue = Output Links