"I'm wondering if you would run into heating/warping issues on the sheave brake. It would take a while for heat buildup though due to the large circumference and "relatively" slow speed."
I thought about that prior to drawing and came to the conclusion that most likely any friction generated heat would be small to begin with and easily dissipated for the same reasons you state .
"Also, you may be limited by the amount of force you can apply before being limited by the structural integrity of the sheave. What I mean by that is with a shoe in just one place on the circumference it would constantly be trying to push the sheave "off-center" so to speak. "
Thought about that , too . That's the reason for the roller bearing that would ride on the flat of the belt simultaneously to the shoes pressing against the sheave . The sheave and belt would be pressed together . All that happening while the complete brake 'arm' floats or drifts , forward or back . So , the brake arm adjusts to where ever the sheave is .
"Also, what program did you draw that with?"
The drawings you see above were done using MS Paint . It's nothing fancy , but it's not bad for the price .
Pete .