Scott Kevern

Machine Elements Design Project

The purpose of this project was to design an educational exhibit for COSI (Columbus' Center of Science and Industry). The main design objectives were to:

  1. Create an entertaining, educational, and interactive exhibit that fits within a 10'x10'x10' volume.
  2. Utilize at least three different machine elements in the design
  3. Provide a detailed analysis of all components for structural integrity and performance
  4. Create a detailed CAD model of the design

**Note -- While the project had a team of 6 students, the work shown here is my own unless noted otherwise.


The purpose of this exhibit is to demonstrate that projectile motion can easily be calculated and controlled via launch angles and different spring constants. The user will select a compression spring, load a ball bearing into the spring-loaded cannon, and input the XY position of the target and spring constant into the computer. The computer then calculates the necessary launch angles and displays them for the user. The user then adjusts the knobs, which control the motion of bevel gears, to match the launch angles of the cannon with the launch angles on the screen. A bearing will be used to facilitate the horizontal rotational motion of the aiming shaft. The user pulls the spring back and launches the ball into their intended target! The joy of aiming a cannon, launching a projectile, and hitting your intended target will keep kids entertained. The ability to use different springs and change launch angles with the bevel gears will teach kids the basics of spring rates and aiming projectile launching systems.


During this project, sketching was used to obtain a consensus from the team and professor on the general design. Several sketches were also created for the table appearance, and team members voted on which one to implement.


Design Overview

The design of the projectile motion exhibit was broken into several subassemblies, with each subassembly representing a functional chunk of the exhibit. These subassemblies were: launch position assembly, tube assembly, table assembly, and table decoration assembly. The purpose of the launch position assembly was to provide a stable support for the tube mechanism, and enable the user to aim the tubes at the desired target using a handle. The tube assembly housed the springs, plungers, supports and other components needed to physically launch the golf ball. The table assembly provided the structural support for the exhibit, and held polycarbonate sheets to separate the children from the flying golf balls. The table decoration assembly was designed to match COSI's fun, colorful, and educational environment.


After the design was complete, all machine elements were analyzed to prevent failure and ensure a very long life. Every stress analysis passed with a factor of safety > 1.25 and a design life > 1 year, so the design met the criteria set forth by the Columbus Science Center. I generated the infographic above for display next to the exhibit, with basic user instructions.

Moving forward, representatives from COSI have expressed an initial interest in implementing this design. More info to come!