Thats because you are translating a linear motion into rotational motion, and that kind of technique has lots of involved physics. Now I did not get your idea, but if you can give a nice drawing xplaining it, might be helpful.
And if I am guessing right, the max pressure zone is very neccessary, since it is the begining of your high torque zone. In the right books you can get a good read with graphs and drawing. I am not a mech guy, but this is all I can say. If I sit and research, that will take my time away from electronics
You can do the mech research right? then let us know you method in good detail with drawing, and please document your stuff. Then you dont have to worry about your idea getting stolen.