Here is an interesting coupling which I call Pin and Gap Coupling. This coupling consist of large number of pins on one disk transmitting power by passing gabs between shield like pins on the other disk.
This coupling can be used to transfer power between misaligned parallel shafts.
The green disk which is closer to the observer contains large number of pins. This green disk is shown as semi transparent to allow the observer to see how the system works. Notice that the yellow disk which contains shields is away from the observer.
Following links show different arrangements of pin and gap coupling.
To better understand this mechanism, I included two 3D images it from different angles.