Transmission design proved to be challenging ME 371 project

This semester in ME 371 (Mechanical Design II), teams of students were tasked with the creation of a two-speed mechanical transmission. Their transmission needed to lift a mass at a specified speed, engage a brake mechanism to hold the mass in place, and then lower it at a different specified speed. 

Throughout the project students had to determine methods to engage and disengage different gears, as well as how to smoothly shift between them.  Teaching Assistant Professor Kevin Wandke and Lecturer Brian Mercer, this semester's course instructors, said the teams were also challenged to take special precautions to ensure that no part of their mechanism failed under the relatively large loads that their designs were subjected to.

This year the teams were also graded on the total weight of their transmissions, with extra credit being awarded to teams with light designs. As a result, some teams opted to make really small transmissions, or to implement other weight-saving measures such as removing excess material. 

The transmission must:

1. Raise a 2kg mass 5 ft in 10 seconds (+/- 2)
2. Hold the mass in position for 4 seconds
3. Lower the mass 5 ft in 15 seconds (+/- 2)

The input to the transmission was a large electric motor providing a constant input of 30 rpm, and the output was a pulley with a diameter of 4 inches. A diagram of the setup is shown below.