[Alex.Norton]

I don't know, I think it is easier to simply say that If the tourque didn't increase as the speed decreased the box would start getting hot a lot faster than normal or would start vibrating a lot. Which ever way the power comes out if your talking 100 watts of lost power I would think that it would become pretty obvious.

From what I see I think the way that it effects to output speed is by changing the length of the arc that the output shaft moves through every time the lever engages the clutch. For higher output speeds it move the lever through a very large arc and for lower output speeds it moves the lever through a small arc.

Thats what I get from looking at the animation.