An Intermittent Counter Drive.

Driver disk has a black pin which is used to push against red arm of driven star. For each revolution of driver disk, driven star rotates 120 degrees. Black pin pushes red arms for 60 degrees and blue arms are pushed another 60 degrees by grove on the driver disk. During the dwell blue arms of the driven star are locked on the side surface of driver disk.

I find hard to model this one very accurately. However this animation gives you an idea how this system is working. In reality black pin should never go under red arm, and blue arm should be pushed by grove.