These are heavy-duty toilet seat fittings. They might not fit your pan or seat, so I have uploaded the FreeCAD file so you can adjust them as necessary. 

There are three parts: the base or main knuckle of the hinge itself, the lower arm that connects to the seat, and the upper arm that connects to the lid.

The FreeCAD file is a bit of a mess, so if you tidy it up please upload it to Youmagine and link from here to your tidied-up file so everyone can benefit!

I have included mouse ears for the base when printing to prevent distortion. I printed directly to heated glass and they worked reasonably well, but nowhere near as well as using glue stick.