Print flip up base out of 98a tpu 60% grid or cubic infill. 

Print handle support bar out of pla+ or something stronger 60% cubic infill

Print right handle grip out of 95a tpu 20% gyroid infill

Print friction sleeve out of 95a tpu (you may have to tinker with horizontal expansion to get the right amount of friction you desire to stop handlebars from falling forward

This setup relies on friction to keep the handlebars in place. Will upload two different locking mechanisms soon. One is an add on to stock handle, the other is a remixed handle from a Veteran Patton armour set. 

Stay tuned and enjoy ;)