Crank-Slider Mechanism

The Idea

As a test to increase the complexity of the 3D piston assembly and to further explore the wonders of mechanisms that drove the industrial revolution I present you a modular crank-slider mechanism. I wanted to remove the idea of a manual crank and allow the satisfaction of watching the mechanism actuate by itself making tolerancing all the more important

Design

I knew the design would need to incorporate parts that could not be printed for the mechanism to function seamlessly and give the intended visual. For example, bearings, connecting rods, and cylinder needed to be outsourced in a creative and resourceful manner. The cylinder needed to be transparent to demonstrate the linear motion of the piston, a perfect solution to this was using a pill capsule. The bearings were refurbished from my skateboard wheels, and a headless bolt and brass tubing were used as connecting rods and thought they would add a nice aesthetic to the otherwise old fashion design.

Assembly and Challenges

Placement and tolerance are always a big consideration when making a multipart assembly and from experience if not modeled prior to manufacturing, it can yield some real challenges when mounting components. Making proper alignment of the connection rod, crank, and cylinder was crucial to enable each stroke of the piston to be parallel and concentric with the cylinder. Another thought that came about was how I could make sure the piston head would actuate to the end of the cylinder when a single stroke passed just like a real engine. Given the degrees of freedom throughout the system, the best way to go about this was through testing it out in the flesh and making markings on the wooden platform based on the fully extended position of the piston head.