This part is based on the excelent http://www.thingiverse.com/thing:82533, it fixes a problem for me, where i need a small fan on the side of the extruder to keep the incoming pla filament cool and stop it from softening when heat creeps back from either the extruder motor or the hotend. This tends to cause the PLA to soften and it buckles and jams.
I did not want a fixed structure as i still need access to the cavity to fiz jams.
The solution was a little trinket box, altered to make it into a fan mount.
The mount is fixed to the extruder by removing and reinserting the two hot end mounting bolts through the two holes provided.
The Latch is still a work in progress, mine where "too fierce" and ended up broken after a few open/close cycles, so I ended up just using a small piece of tape to keep the box closed for now.
I have included the openscad file for those that want to play, its based on the original trinket box, but hacked to produce the fan mount, it took about 5 prints to find a set of parameters that did not result in either a weak or fused hinge on the printrbot.
DONT print with support material turned on.
NOTES: this item will challenge your Printrbot simple, it has to be well setup to print this as the object is printed in one part and is 98mm wide. It wont print if you have a skirt turned on in slic3r, so turn it off. Before you print, bring your hotend up to temp, and run out 10mm of filament to get the extruder flowing.
UPDATE: the latest version of slic3r (9.10) seems to have broken this item, it does not slice the hinge properly, previous versions worked fine.