Input: grey shaft having internal cylindrical surface with grooves.
Output: green shaft having cylindrical joint with blue disk.
Pink friction disks engage with the grey shaft.
Orange friction disk engages with the blue disk.
In normal condition the green spring forces blue, pink and orange disks towards the disk of the green shaft to connect the clutch.
When overloading (represented by the pink pin position), the green shaft is kept immobile, the red balls (located in cone holes on faces of the green shaft and the blue disk) push the blue disk to the right, thus disconnect the clutch. At that time there is no contact between the disks so their wear is reduced remarkably.