Ahhhh, no that makes sense. That large screw is the axle that the cam turns on and if it got tight then it would lock up things. Two things are going on...the cam should turn freely so as not to tighten the screw, and the screw (I think) should have a nut on the back side so it is "locked" in adjustment...(either that or it should have a shoulder on it so that it can't get to tight.
I did not take the winder assembly that far apart img mine. I can check tonight and see if I cam help you out somehow.