Basic clutch question
 

I have two cubs and im getting ready in the next few weeks to start tearing them down and learn as I go, and rebuild them. I have a simple question, that most may seem as obvious, but i cant find a good explanation anywhere online so i am posting it here. I like/have to fully understand how things work or it really gets to me, anyways here is my clutch question.

How exactly does the clutch work? how does it stop the rear tires from turning and still have the drive shaft turning? I am looking for a simple clutch explanation for IH cubs, i just cant understand how it works, does the shaft run straight from the trans to the motor? if so then how does the rear stop when the clutch is engaged? anyways sorry for my lack of knowledge but i just want to do this right and this is the one question i can not find a good answer for, thanks for any help with this.

btw my two tractors are a 100 and a 122

Take a look at the section view diagram in the service manual. The friction disc clamped between the two pressure plates is driven by the 3 pin driver on the engine and always rotates with the engine. The driveshaft is connected to the transmission input shaft on one end, and the other end pilots in the 3-pin driver and rotates freely in it. One pressure plate is pinned to the driveshaft and cannot move relative to it; the other must rotate with the shaft but can slide back and forth. The main spring forces the sliding pressure plate against the friction disc and other pressure plate. The friction between the pressure plates and friction disc transmits the engine power to the driveshaft. When the clutch is disengaged, the throwout arm pushes on the bearing,which compresses the spring. With nothing clamping the pressure plates together with the friction disc sandwiched in between, the friction can rotate freely between the pressure plates. The driveshaft does not turn while the clutch is disengaged.