This is a remix of prior geared hinge updated so that it can be printed in place as a single assembly.   Tested with 210lb/95KG of weight using two hinges (as shown in second picture) with no sign of failure or sagging.  Printed in PLA / .4 nozzle / .16 layer height/no supports.   Print with gear columns vertical.  I used 7 perimeters for the print used in test - probably overkill for most needs, but wanted to see what the basic model could do.

Even with a clean print, it takes a good bit of torque to get initial rotation, should swing freely after that.  STL defaults to upside down on build plate when it opens, flip for best results.

 Link to Solid Works Gear Generator app for your own designs with gears.

Also added mesh file for a double height version for even heavier loads.

Smaller versions available at https://www.prusaprinters.org/prints/124967-print-in-place-mini-gear-hinge-assortment