One of the things I really admire about Shaker Robotics is their unique use of COTS parts in many applications. Sometimes, we don’t have the equipment or machinists needed to hold tolerances needed for stuff like gearboxes. Other times, the off the self part used in a way no one ever intended is a fast and light solution to the problem at hand. Either way, the team members always find a way to use off the shelf components in creative applications.

Vex 5 inch wheels on the robot's orbit ball shooter.

In 2009, before I joined the team, 2791 used some Vex wheels on the robot’s turreted orbit ball shooter. They looked weird but they were really the obvious choice. Dirt cheap, already fairly perimeter-weighed, much lighter than an AndyMark wheel and hub. The wheels needed set screws, but a ball shooter is a low load application. Plus they had a cool factor that gathered a bit of attention at competition events. The shooter assembly was problem free all year, so I’m told.

In 2010 there were a few different situations where we needed to accomplish something that we couldn’t quite do ourselves. Our hanging mechanism was to winch our robot up in the air with a reduction of around 45:1, but we didn’t have the skills necessary to make our own gearbox. We also had to stop the winch from backdriving. Banebots planetaries were a no-go for our team, and unfortunately my team’s leader had an aversion toward the Dewalt gearboxes which would be perfect for the application. So the team got creative again.

Shaker's winch, with servo shifting wrench and modified AM parts

We figured out that you could feed a CIM through an AM Planetary with some modifications to the sun gear and the CIM output shaft. Since we already had an AM Planetary, all we needed to buy was the relatively inexpensive Toughbox Nano in order to achieve the reduction the design called for. While the design wasn’t free of problems (the Nano’s AL shaft failed under load, so we made one out of steel), it worked just fine for the amount of effort it took us in design. For a ratchet, we just took a wrench and put a 1/2 hex socket on the end. It eased the cantilever on the shaft and stopped the device from back driving. The servo was intended to “shift” the ratchet in the direction the motor spun the gearbox, but we changed our design to run in only one direction in order to have one less thing to debug.

I’m rather proud of these little solutions using off the shelf parts. Next year we’ll have a few more.