A screening plant like this?
http://www.youtube.com/watch?v=yarck1mWz8E
I'd be interested in aquiring a jaw crusher myself. A four or five inch opening capable of crushing tennis ball size rocks to pea size.
I have some pics of one german modeller's start of one a few yrs ago, but hasn't yet finnished... don't know why.
PM email addy & I could send them to you.
Have you considerd getting a patent for your 4axis prosthetic wrist? It looks pretty trick!