To facilitate the rapid changing of nozzles, I designed a method by which the entire hot end (the nozzle, heater ,thermal barrier and cooling shroud) can be removed in a tool-less manner. The system consists of a keyhole shaped stand into which the hotend snaps into place. The red handle is used to push the hot end forward just enough so that it snaps out of the keyhole.
Although somewhat costly, this method would vastly decrease the amount of time normally taken to switch from one nozzle to another.
The hotend cooling fan is connected to the back of the mount so that it does not need to travel with the rest of the hotend. There is a hole that allows air to flow through to the heat sink.