2 April 2019, The Pedal Mechanism Works
Big Wheel Lift #1
All of the Jim’s Gym series automata work with the concept of a biped (a Jim’s Gym Club member) exercising. The power for the Big Wheel Lift is generated by a biped pedaling and pulling levers. I’ve not yet created a biped pedaling…so for a little more than a week have been focused on the pedaling part of this automata.
Part of the process is simply figuring out proper geometry and dimensions. Then the construction process must allow everything to fit and to operate smoothly. In the Jim’s Gym series I want all of the bipeds to be the same size, and in fact I am hoping to be able to create them all to the same template. I also want them to be able to easily be removed from the assembly.
It quickly became apparent to me that the axle for the pedals, and the pedals themselves were not going to be a trivial piece of work. My goal is always to build durably, with smooth operation for thousands and thousands of cycles. In this case I’m using two ball bearing on the 1/4″ axle, and then nylon bushings for the pedal bearings. All of this needs to be created to relatively small dimensions. I realized that I would not be able to use even #2 fasteners because of their bulk and so would use CA glue. This means that this first pedal assembly must be well thought out before assembly because it will be glued, not screwed, and therefore will not have serviceable parts…but rather will be an assembly that must be replaced as a whole if it develops problems. The goal, of course, is to have no problems.
The pedal assembly that you see in the image to the right is a portion of a biped test stand which I am making specifically for this Big Wheel Lift series. The test stand will be to the same dimensions as those on the actual Big Wheel Lift. The biped will be able to easily be removed because it uses a socket and magnets for attachment. The test stand is powered by a small electric motor. The biped will be put through thousands of cycles before it will be placed into the Big Wheel Lift assembly. I will post a video of this test stand after it becomes operational.
Bottom line…just this evening I got the biped pedaling properly. I was simply hand cranking…observing…and am pleased with how it all looks in action. Now to get the levers and the motor installed into the test stand. Perhaps another week…maybe a bit more.